LIVE FROM THE AURORA - "Live from the Aurora"

The more sunspots, the more active the sun, i.e. more active regions, which produce flares and coronal mass ejections. It's these mass ejections and high speed wind streams from coronal holes that produce the beautiful aurora.

Check out

http://www.spaceweather.com/

for real-time space-weather and aurora info.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
Is it possible to predict an Aurora?

ANSWER:
Yes, because auroras are ultimately caused by the sun. So with telecscopes that look at the sun and with instruments that measure the solar wind, we can predict when there might be auroras. The chain of events that leads to an aurora is given below:

The weather in space comes from the sun. The sun's atmosphere is very hot, millions of degrees, and is constantly blown away from the sun. This wind is called the solar wind. It can be very fast or very slow, very dense or not very dense. The very fast, very dense solar wind has the most effect on the planets.

Space weather is term which generally means the effect of the solar wind on the planets and the regions around the planets. For example, if a large solar flare (bright spot) occurs on the sun, the flare is like an explosion on the sun and pushes even more of the solar atmosphere into the solar wind. If that part of the solar wind strikes the earth, it causes changes on the earth and in space above the earth. For example, auroras are caused in the high latitudes of the earth. At the same time huge currents (one million amperes or more!) are set up in the ionosphere above the aurora. These currents cause currents in conductors below the aurora, for example, power lines or pipelines. Currents in power lines have caused them to burn out. Currents in gas pipelines have cause them to explode. So space weather can really have an effect on the earth! Space weather causes aurora and currents in other planets, too, for example, Jupiter.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
What is the aurora made of?

ANSWER:
The aurora is light: green, blue, red and various combinations. The light is emitted from atoms and molecules of air, that is, mostly oxygen and nitrogen. The atoms and molecules that emit the light have been struck by fast moving electrons that come from outer space. When struck some of the energy of an electron is absorbed by the atom or molecule, leaving it in an excited state. It can't stand being excited very long, so gives off its extra energy in the form of a photon, or light. If enough atoms and molecules have been struck, that is if the beam of electrons from outer space is sufficiently intense, then enough photons are emitted so that we can see the aurora with our eyes. Since the air atoms and molecules have to be struck by the electrons, they have to be high enough up so that the electrons can reach them. The altitude of the aurora is usually about 90 to 150 km.

Now where do these electrons come from? That is another whole question. They probably do not come from the sun like most text books and web sites will tell you. They are accelerated in outer space around the earth by very complicated processes. But the energy they obtain did come from the sun by means of the solar wind.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
Are there incidents or concerns regarding human eye safety of aurora observers, on Earth's surface or airborn?

ANSWER:
The light from auroras is very dim, so there is no possibility of being harmed by auroral light, either on the ground or airborne. Auroras are often so faint that they can't even be seen until your eyes become dark adapted, that is, until your iris opens wide and the sensors in your eyes relax and become more sensitive. This may take 10 or 15 minutes.

The aurora is beautiful, but can be faint!
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
Why is 5:00 AM the best time to see the aurora?

ANSWER:
I've never heard that 5:00 am is the best time to see the aurora. I would say that midnight is the best time, since the sky is darkest then. The timing of aurora is influenced by events on the sun, which doesn't know what time it is on earth. And, of course, its different times at different parts of the earth!
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
What would be the rarest aurora seen in the sky?

ANSWER:
This a really interesting question. I think I will try to give you two answers, depending upon just what you mean. In the auroral zone, where the aurora is most common, the rarest aurora seen is probably the corona. The reason is that the observer has to be located directly below an aurora that is composed of two or more very narrow arcs. In general, the rarest aurora would be an aurora seen at very low latitudes, say in Puerto Rico. This may occur once every solar cycle (11 years) or less. Also a rare aurora is a very red aurora covering the entire sky seen at mid-latitudes. The most famous one occurred back in 1958.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
What is an aurora made of?

ANSWER:
The aurora is caused by energetic particles, mostly electrons that strike the atmosphere and make it glow. This is just like the way a television screen works. In a television tube, electrons are accelerated to high energies and pointed to various parts of the screen. When they hit the screen, it glows.

So an aurora is made up of the particles that hit the atmosphere, the atoms that glow and the glow itself, which is light in the ultraviolet, visible and infrared portions of the spectrum.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
Does the aurora occur only on Earth?? Do they occur anywhere else???

ANSWER:
Auroras occur on many planets, those with intrinsic magnetic fields, like the earth. The planets with the strongest auroras are the earth and Jupiter. Saturn, Uranus and Neptune have weaker aurora because they are farther from the sun and the solar wind is less dense. A phenomenon that is similar to the aurora is called airglow. Planets with atmospheres, but no intrinsic magnetic fields have airglow, like Venus and Mars.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
What is the arurora?

ANSWER:
The aurora is a faint glow in the sky. It is too faint to be seen in daytime or when there are too many city lights around. But if you can find a place where the sky is good and dark, and if you live far enough north, and are patient enough to go out and look on a number of nights, you may be able to see an indescribably beautiful display of white or green or red lights in the form of hanging curtains or rays of diffuse glows. They may move and change colors, and appear and disappear like waves on the ocean, always changing, never quite the same.

The trick is to live far enough north (65 or 70 degrees latitude - or south); then you can see auroras frequently. If you live at lower latitudes, such as Iowa or Maryland, or Texas, you may still see an aurora occasionally, but only perhaps once or twice in eleven years.
Dr. Don Michels
Naval Research Laboratory

QUESTION:
During what season do auroras occur?

ANSWER:
Auroras can occur at any season. In fact, there is some auroral glow going on essentially all the time. You just have to be in the right place and have the right conditions to see it.

The RIGHT PLACE: auroras occur mostly at about 65 - 70 degrees north (or south) latitude. Look up your latitude on a map and see whether you are far enough north. If not, wait a while - when there are really big solar storms (which happens at the time of maximum solar activity - most recently 2000 - 2001) you may get to see the aurora at much lower latitudes.

You can get an aurora forecast from the University of Alaska's Geophysical Institute (in Fairbanks) by looking at the Web site:

http://www.gi.alaska.edu/cgi-bin/predict.cgi
Dr. Don Michels
Naval Research Laboratory

QUESTION:
Why is it that the aurora has more of one color at certain times?

ANSWER:
The colors one sees in the aurora are caused by the light given off by atoms in Earth's upper atmosphere when they are hit by energetic electrons from the Sun. If a nitrogen atom is hit, it usually glows blue. If an oxygen atom is hit, it may glow red or green, depending on how hard it was hit by the speeding electron. Usually both oxygen and nitrogen atoms are being hit and the colors generated may mix to appear white, gray, violet, yellow, etc. At different times, depending on the energy of the incoming electrons, density of the atmosphere, and conditions in Earth's magnetic field, one or another color may predominate.
Dr. Don Michels
Naval Research Laboratory

QUESTION:
How long do they last?

ANSWER:
Auroral displays more or less correspond to times of rapid changes in the Earth's magnetic field called "substorms." These typically last 30 to 60 minutes, and occur in sort of "bursts." I.e. There may be a burst of activity with its luminous auroral display for a half-hour or an hour, then it may be quiet for several hours, then start again. Sometimes, when there is a very violent storm on the Sun that really disturbs Earth's global magnetic field, a big auroral display may occur. It may get very bright, last a number of hours, and move to much more southerly latitudes than places like Norway (where it is seen all the time!) In cases of a really big solar storm, it may be possible to see auroras even as far south as Texas!
Dr. Don Michels
Naval Research Laboratory

QUESTION:
When was the first recorded aurora? -B.C.

ANSWER:
The aurora has no doubt been seen for as long as there have been eyes to see it. I don't know when the first written account of the aurora was recorded, but there was a fine description of auroral characteristics written in the year 1230 A.D. by an anonymous Norwegian author. The Greek philosopher Aristotle gave what may have been the first scientific account of aurorae in the 4th century B.C., describing it as 'glowing clouds' and as a light that resembled flames of burning gas.

There may be even earlier accounts, and there are investigations going on right at this time as to whether the Old Testament biblical prophet Ezekiel may have seen the aurora when he described his vision of lights in the night sky. Now, Ezekiel lived in Mesopotamia (Babylon) at the time, which is not far from modern Baghdad. For the aurora to be seen at such a low latitude, the Earth's magnetic field (i.e. the north magnetic pole) would have to tipped considerably from where it is nowadays. And there is considerable evidence that it was!! That's what makes science so amazingly interesting!
Dr. Don Michels
Naval Research Laboratory

Coronal Mass Ejection

QUESTION:
I learned that CME's can have so much mass that it could be compared to the mass of 1000 luxury cruiseships. If they are so massive, could they have inflicted some damage on the space shuttle Columbia while in orbit?
Western Adventist School (Mayaguez, Puerto Rico)

ANSWER:
Dear Writer,

Yes, you are correct about the mass involved in a CME. However, we have to put that fact in context. We are talking about particles that are heading out into space, expanding as a huge cloud over 30 million miles wide by the time it reaches Earth. In fact, at Earth its density is so low that it would not even be enough to create a breeze, if there were such a thing in space. So, no, it could not inflict physical damage on the shuttle. A shuttle could be impacted by radiation from such a storm or one like it, but there is no chance for physical impact. thanks!
Steele Hill
SOHO Media Specialist
NASA Goddard Space Flight Center

QUESTION:
During a major solar ejection event that produces lots of material that is caught up in our magnetic fields, is it dangerous for people to be at the magnetic poles? or certain equipment? Or is everything so high up in our atmosphere that people on Earth's surface don't have to worry.

ANSWER:
Hi!

Thanks for the very good question!!

The amount of material that is intercepted by Earths magnetic field is only a few hundred tons or so, which is not enough to worry about. At Earth's surface, our atmosphere is such a good shield that none of these particles penetrate to the troposphere or lower. Now, if yo uwere in a high-flying passenger jet crossing the poles, you would get mildly blasted by energetic particles and cosmic rays which can give you the equal of a chest x-ray during a 6-10 hour exposure. In fact, flight crews spend nearly a thousand hours a year at these altitudes, and in Europe they must wear radiation dosage badges to monitor their exposure. We don't do that yet here in the USA, but the FAA is studying this issue and the airline workers union is very much in favor of this monitoring.

Hope this answers your question!
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

QUESTION:
1. Are solar mass ejections dense enough, that they would "burn" a massive object or a planets atmosphere?

2. Do you have any information / literatur(!?) about the energy-density in the gaseous clouds of a supernova ? Would it be, in the distance of some lightyears away from the explosions epicentre, energy-loaden enough to burn a planet or are they just relativly diluted plasma-clouds sending out light/radiation that are absorbed by a atmosphere like our terrestial ? Would their impact be comparable to our "normal" solar winds ?

Thank you for the nice opportunity to ask !

Matthias Regier,
Teacher, Hamburg (Germany)

ANSWER:
The energy density in a coronal mass ejection is small: at earth's orbit the typical density is ten's (say 50) protons per cubic centimeter, with a temperature of around 1 million K. The total heat in this is tiny, so it doesn't heat up a spacecraft, for example.

The same is true of a supernova blast wave once it is some distance (you say lightyears) from the source. The X-ray and gamma ray radiation from a supernova will of course heat (and ionize) any atmosphere it its way, but the force of the gas is insignificant on any solid object (planet, star, or even spacecraft).
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
What are the materials that are ejected from a coronal mass ejection?
-D.S.

ANSWER:
A coronal mass ejection is made up mostly of hydrogen and helium nuclei, electrons, and magnetic field energy. It behaves like a huge electrical/magnetic bubble that blows off into space. The reason it's mostly hydrogen and helium nuclei is because the Sun is mostly made up of those two elements--and these are the lightest elements, too, and more likely to escape the Sun's gravity during the explosion.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What are the materials that are ejected from a coronal mass ejection?
-D.P.

ANSWER:
The mix of "stuff" that is ejected in a coronal mass ejection is the same "stuff" that the sun is made of -- mostly hydrogen, about 5% helium (by number, that is one helium atom for each 19 hydrogen atoms, by mass the fraction is higher)and small traces of heavier atoms (mainly oxygen and carbon). The gas is so hot (1 million degrees) the the hydrogen and helium is completely ionised, so really its a mixture of protons, electrons and helium nuclei (alpha particles).
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
What are the materials that are ejected from a coronal mass ejection?
-D.S.

ANSWER:
Hi!

Great question! The material has nearly the same sbundance of elements as the sun itself - mostly protons (hydrogen) and helium nuclei. Heavier atoms are harder to accelerate because they are more massive.
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

Earth's Magnetic Field

QUESTION:
Do you know what an IMF is?? How does it affect space??

ANSWER:
The IMF is the interplanetary magnetic field. This is the magnetic field in the solar atmosphere which is swept out by the solar wind into the space between the planets. The magnetic field makes a neat pattern in space called the 'Parker Spiral' caused by the solar rotation. The way the IMF affects space is that may particles travel along the field lines. Storms can occur when matter traveling along the IMF collides with a planets magnetosphere.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

Earth's Magnetic Poles

QUESTION:
Does any harmful effect exist for the organisms that live in the magnetic poles due to the flows of energetic particles that are given?
Miguel Toledo from Universum Science Museum in Mexico City

ANSWER:
Not at the ground. Earth's atmosphere is a thick blanket, and it shields us from these particles. Passengers in high-flying aircraft may experience a minor hazard (similar to having an x-ray) during a large solar proton storm.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
What does it happen with the magnetosphere during the inversion of the magnetic poles?
Tere Mendiola from Universum Science Museum in Mexico City

ANSWER:
Nobody knows how a pole reversal is actually going to happen: does the magnetic field just turn off, and then turn on again with reverse polarity? Does the pole start moving towards the equator and then up (or down, depending on your point of view) towards the other side?

What we can say about magnetospheres in these two scenarios comes from observations of other planets. Venus, for example, has no magnetic field, but a dense atmosphere. We can see that such a planet has an ionosphere with some very strange and very weak aurora all over the dark hemisphere, but there is no magnetosphere. Uranus, on the other hand, has a magnetic field such that the magnetic pole is on the equator, so we can see what the magnetosphere in such a situation looks like. What we have there is a twisted magnetosphere that changes very rapidly over the course of a day. The aurora on Uranus is also very strange, strongest during high noon, and best seen at the equator.
Dirk Lummerzheim
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
How do you track a single electron to estimate the time taken for it to reach from pole to pole?

ANSWER:
We cannot track single electrons. What we do see are clusters of electrons bouncing from pole to pole, and we can measure the time that the whole cluster takes. You can see this for yourself, if you are lucky enough to witness "pulsating aurora". The time between pulsations is the time for the electrons to travel to the opposite hemisphere and back.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
Do the magnetic poles effect the distance between the surface of the atmosphere and the surface of the Earth?

ANSWER:
No. The magnetic poles are caused by electric currents deep in the core of the Earth and don't affect the atmosphere height directly.

Space weather can cause the atmosphere to heat up, however, and make it extend farther into space.
Dr. Patricia Reiff
Rice University

QUESTION:
Is the north pole the north magnetic pole? So when you use a compass is the south pole of the compass needle pointing at the north magnetic pole?

ANSWER:
The north magnetic pole is not at the (geographic) north pole. It is presently in an island off the north coast of eastern Canada. Where is live the deviation (that is the difference between magnetic north and true north) is about 10-15 degrees.

The earth's north pole is really a magnetic south pole. A compass's needle is a magnet and the north end is a north pole (or south seeking pole), so it is attracted to and points to the earth's north pole, because it is a magnetic south pole.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
Is the north pole always staionary? We learned about something but I didn't understand it.

ANSWER:
You learned about the north magnetic pole. That's the place where the earth's magnetic field (and so a compass if you had one that worked in its side)points straight down (or up in the southern hemisphere). Right now these two points are in northern Canada and just off the coast of Antarctica, in the same general vicinity but not very close to the regular geographic poles (the points about which the earth spins). The magnetic poles move slowly, at speeds of a few miles per year. These are small, but measurable, changes.

If you look, for example, at a good topographic map (such as might be used for hiking) the compass mark will tell you by how much magnetic north and true north differ, and also by how much this changes each year (usually a very small fraction of a degree).
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

Effects on Earth

QUESTION:
Why does effects on Earth make people sick?

ANSWER:
The only way that people may become sick from space weather is if they receive alot of radiation from the sun, meaning an extreme sunburn. People must be aware of the sun and protect themselves from sunburns by wearing sunglasses, hats and sunscreens.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
How exactly does the magnetic energy of the sun affect communications on earth?

ANSWER:
The answer to this isn't simple as it is a many stage process. Many communication systems either depend on bouncing radio signals off the ionosphere (HF and AM radio) or on sending radio signals through the ionosphere from the ground to a satellite or vice versa. The ionosphere (which is the ionized part of our upper atmosphere) is created by and is sensitive to solar radiation. When the sun gives off sudden bursts of radiation (say from solar flares) this can cause turbulence in the ionosphere or create enhanced levels of ionization that can block or scatter radio waves, thus disrupting communications. Solar flares and other solar disturbances are caused by the sun gradually storing up energy in its magnetic field and then releasing it suddenly. So the connection between solar magnetic fields and communications.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
What are some of the effects that solar storms have on Earth?? How do you know that they do effect earth??

ANSWER:
Energetic particles traveling at the speed of light impact the Earth's atmosphere. They don't hit the ground directly, but create a "shower" of secondary particles. They can directly interfere with electronics in space (or in highflying aircraft over the poles) by flipping a "bit" in the computer memories. This can cause a "phantom command" that can cause the loss of a spacecraft (by turning on a steering jet, for example).

On the ground, the effects to electronics can be caused by the increased ionization in the ionosphere causing radio disruptions.

Electronics can also be harmed several days later, when the blast of plasma from the Sun (a "Coronal Mass Ejection") hits the Earth and affects the ionosphere. Electrical currents in the ionosphere can induce currents electrical systems on the ground and blow transformers and delicate systems.

Also several days later, a buildup of very energetic electrons ("killer electrons") can cause problems with geosynchonous satellites.
Dr. Patricia Reiff
Rice University

Electromagnetic Spectrum

QUESTION:
What is electromagnetic spectum?

ANSWER:
In a rainbow you see the spectrum of visible light, from violet through green and yellow to red. The color depends upon the wavelength of the light, the violet light having a shorter wavelength than the red light. Visible light is a form of electromagnetic energy, all of which are electromagnetic waves; that is, they are both electric and magnetic in nature. Other forms of electromagnetic energy are ultraviolet, which extends the spectrum from the violet to shorter wavelengths, and infrared, which extends the spectrum from the red to longer wavelengths. Radio waves have even longer wavelengths. On the other side of the visible light, X-rays have shorter wavelengths than ultraviolet, and finally gamma rays have the shortest. If you put all these different forms of energy together on a chart, you get the electromagetic spectrum

Since the energy carried by an electromagnetic wave gets larger the shorter the wavelength, gamma rays have the most energy, and therefore, can penetrate through material the easiest. This is why X-rays are used to look for broken bones in the body and not infrared light, which cannot penetrate the skin.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
Is the electromagnetic spectrum visible or related to the aurora at all?
C.O and J.O

ANSWER:
The aurora is light and light is part of the electromagnetic spectrum. Light is that part of the electromagnetic spectrum that is visible to us.

The electromagnetic spectrum also has components with much shorter wavelengths, like Xrays and much longer wavelengths, such as radio waves.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
What types of radiation is given off from the electromagnetic spectrum?

ANSWER:
The spectrum of electromagnetic waves encompasses the full range of frequencies, from radio waves to gamma rays.

A nice introduction of the electromagnetic spectrum is available at:

http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html
http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html
http://imagers.gsfc.nasa.gov/ems/ems.html
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

Magnetism

QUESTION:
Who was the first to discover magnetism and how did they first experiment it?

ANSWER:
The discovery was lost to history but was probably in ancient CHina around 2000 BC or earlier, when the use of a lodestone-like substance was mentioned as a navigation aid. Magnetism was studied several times, but a detailed description had to wait until 1600 when Gilbert - a court physician -wrote his book 'De Magnete'
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

QUESTION:
Does magnetism in the sun have any direct effect on the Earth?

ANSWER:
The Sun's magnetic field affects whether the energy in the solar wind and in Coronal Mass Ejections (CME's) are able to connect to the Earth. Without the connection, the flow from the Sun bounces off the Earth's magnetic field. But if the magnetic field in the solar wind is aligned opposite to the Earth's magnetic field, the two fields can connect and energy and particles are transferred from the solar wind to the earth, and major effects in the ionosphere can be felt. Some of those can harm electrical devices and radio communication on earth.

The magnetism is the transmission line! It doesn't affect earth directly, but it allows the energy to flow.
Dr. Patricia Reiff
Rice University

Magnetosphere

QUESTION:
Do any special events happen in the magnetosphere?

ANSWER:
Yes, the magnetosphere has special times where it is very active. One is called a "substorm", when the auroras get very bright. That happens when the sun's magnetic field puts energy into the magnetosphere. A "storm" is larger, and often has many substorms. Those often follow a large "coronal mass ejection", a blast from the sun.
Dr. Patricia Reiff
Rice University

QUESTION:
Do any special events happen in the magnetosphere?

ANSWER:
Yes...many. There are magnetic storms that can trigger aurora at the poiles .There are poorly-understood particles storms that cause electrons and protoins to get boosted to millions of volts of energy, and sometimes disable satellites. Eareths magnetic field is very complicated in space, and the changes cause all sorts of things to happen, and currents of particles to flow.
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

Solar Cycle

QUESTION:
Is there a pattern for when storms on the sun occur?

ANSWER:
There are two dominant patterns. Activity on the Sun varies in an 11-year cycle. At the peak of the cycle, storms occur much more frequently. At solar minimum there may be no storms on the Sun at all. The "active regions" of the Sun also persist sometimes for many months. Because the Sun rotates roughly once per month, here on Earth we see storms repeating monthly,as the same region rotates around to face the Earth.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
Can the sun burn any of the planets?

ANSWER:
No, at least not for another 4 billion years. That's when the Sun will have burned most of its hydrogen and will change into a giant star, swallowing Mercury and Venus, and possibly even Earth.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

Solar Flares

QUESTION:
What are solar flares and what are they made out of?

ANSWER:
Solar flares are huge releases of energy that occur when magnetic fields are converted into heat. They are made up of 'hot stuff'- hot plasma - and they can accelerate particles towards earth or spacecraft.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
How do solar flares interfere with electronic devices on Earth?

On the ground, the effects to electronics can be caused by the increased ionization in the ionosphere causing radio disruptions.

QUESTION:
What are solar flares and how do they form?

ANSWER:
Solar flares are rapid (sometimes said to be explosive -- they last a few minutes) releases of energy in a relatively small area just above the solar surface. Energy is stored-up in the sun's magnetic field which gets twisted, not unlike twisting up a rubber band. If too much energy (twist) is confined to too small a volume, the magnetic field lines "break" (or "reconnect") releasing that pent-up energy into heat and fast flows of gas. This produces light, and also, as the newly hot gas slams into the sun's suface, x-rays and gamma rays. They can also produce high energy electrons and protons that can travel to earth in 10-15 minutes (the light an x-rays take 8 minutes).
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
Are solar flares dangerous to the human eye?

ANSWER:
Looking at the Sun in general is dangerous to the human eye, flares or no flares. The intense light the Sun emits can permanently damage your eye. In a solar flare explosion, a lot of X-rays and ultraviolet light is emitted, as well as clouds of electrically charged particles. For the most part, however, the X-rays and ultraviolet radiation are blocked by Earth's atmosphere and do not reach the ground, and we are shielded from the charged particles by Earth's magnetic field. So, as far as the effects of a flare are concerned, we on Earth are mostly protected from the radiation.

But always remember, it is not safe to look at the Sun because of the intense visible light it always shines.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What are solar flares and what do they do? Are they dangerous?

ANSWER:
Solar flares are sudden releases of energy in a relatively small region sun above the sun's surface. The energy gets stored in magnetic fields -- magnetic fields strengthen, and the force lines get twisted much like twisting a rubber band. If the energy gets too great the magnetic field lines "break" or "reconnect" and the energy released heats up the gas locally and also accelerate it into fast flows. Flares release light, and as the newly hot gas slams into the sun, they release X-rays and gamma rays. They can also create energetic electrons and protons that can reach earth in 10-15 minutes (the light and X-rays arrive in 8 minutes).

Are flares dangerous: not on the earth's surface as we're protected by our atmosphere which absorbes the X-rays and energetic particles. However in space astronauts or satellite hardware gets bombared by the radiation and can be damaged.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
What are solar flares? Does it effect earth, space, the atmosphere? How does it effect us? How does it form? Where does it form? Can we see it? Why does it happen?

ANSWER:
Solar flares are the sudden release of energy on the surface of the Sun, most visible in X-rays and extreme ultraviolet. You can find a very nice descriptions of flares at:

http://science.nasa.gov/ssl/pad/solar/flares.htm and

http://www.windows.ucar.edu/spaceweather/sun_earth4.html

and

http://hesperia.gsfc.nasa.gov/sftheory/

The energy comes from magnetic fields. Think about them as rubber twisted rubber bands, that snap. Flares are often associated with intense particle storms, which can affect spacecraft. The intense UV light also leads to changes in the upper atmosphere and ionosphere of the Earth, causing radio blackouts and other effects (e.g. also the GPS system). See

http://www.windows.ucar.edu/spaceweather/swf_flares.html for more info.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
What instruments are used in finding solar flares?

ANSWER:
Solar flares are rarely seen as optical events on the sun .Instead, astronomers on the ground use special 'solar filters' that isolate the light produced by, say, hydrogen gas. Solar flares appear as brief (minutes to hours) brightenings in the shapes of prominences and sunspots. With X-ray telescopes in space, even clearer images of them can be seen, and this has become a very common way to spot them now that we have satellites with x-ray sensors.
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

QUESTION:
Where are solar flares located?

ANSWER:
Solar flares are located on the surface of the sun around active regions of sunspots. They are very catasrophic disturbances that have sudden onsets and more gradual decays. They emit a large amount of energy in the electromagnetic spectrum, including X-rays that affect the density of the upper atmosphere.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
What are some effects on solar flare and how do they effect it?

ANSWER:
Solar flares are tremendous explosions on the surface of the Sun. In a matter of just a few minutes they heat material to many millions of degrees and release as much energy as a billion megatons of TNT. They occur near sunspots, usually along the dividing line (neutral line) between areas of oppositely directed magnetic fields.

They are most visible in X-ray and UV light. For more in about flares check out

http://science.nasa.gov/ssl/pad/solar/flares.htm

and

http://hesperia.gsfc.nasa.gov/sftheory/

The intense UV light of a flare leads to changes in the Earth's atmosphere, causing radio blackouts and other effects.

More details about effects on the Earth at:

http://www.windows.ucar.edu/spaceweather/effects3.html

A nice introduction into spaceweather issues is available at:

http://www.windows.ucar.edu/spaceweather/basic_facts.html
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
Can scientists predict solar flares before they occur? If so how?
-K.R

ANSWER:
We can't predict the exact occurance of a solar flare. We can identify regions of the sun where one is likely to occur (regions with strong and complexly structured magnetic fields) and monitor these regions (which we do), but that's the best we can do at present.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
Do Solar Flares effect the Earth in any way?

ANSWER:
Yes, the intense UV radiation leads to changes in Earth's ionosphere, causing radio blackouts and scintillation in the GPS system.

The energetic particles accelerated in the most powerful flares can cause damage to satellites and can even be dangerous to highflying airplanes (in particular on polar routes).

More details at:

http://www.windows.ucar.edu/spaceweather/spweather_5.html

and

http://www.windows.ucar.edu/spaceweather/basic_facts.html
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
How long to solar flares last?
C.O & J.O

ANSWER:
Hi!

They last about 20 minutes to an hour.
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

QUESTION:
Can solar flares, prominences, and winds happen at the same time on the sun?

ANSWER:
Yes! They are completely independent phenomena. The solar wind blows continuously. It's not related to flares or prominences.

Prominences are a fairly common phenomena. You can see a collection of some of the most spectacular prominences and prominence eruptions at:

http://sohowww.nascom.nasa.gov/bestofsoho/PAGE3/

and

http://sohowww.nascom.nasa.gov/pickoftheweek/old/

Flares are the sudden release of energy in the solar atmosphere, most visible in X-ray and UV light.

http://sohowww.nascom.nasa.gov/hotshots/2002_07_15/eitframe.gif is an impressive image of a flare.

More info about flares under:

http://science.nasa.gov/ssl/pad/solar/flares.htm
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
Can the solar flares affect the Earth or anything else besides the Sun?

ANSWER:
Solar flares can have considerable affects on the upper atmosphere and ionosphere. Solar flares emit a lot of X-rays, which bombard the atmosphere, heating it and creating ions from the atoms of the air. The heating can cause the atmospheric density to increase, causing more drag on low altitude satellites. The creating of a lot of extra ions changes the characteristics of the ionosphere, affecting varous kinds of radio transmissions.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
What effecs do solar flares have on Earth?

QUESTION:
What was the biggest promince that you have ever witnessed on the sun?

ANSWER:
One of the biggest I recall having seen on photographs is the "Grand Daddy" prominence from 4 June 1946:

http://www.hao.ucar.edu/public/education/slides/slide7.html

http://www.hao.ucar.edu/public/education/slides/slide7.jpeg

Some of SOHO's most spectacular prominence images are:

http://sohowww.nascom.nasa.gov/hotshots/1999_09_14/eit_19990914_0719_304.jpg

http://sohowww.nascom.nasa.gov/bestofsoho/ and

http://sohowww.nascom.nasa.gov/bestofsoho/PAGE3/

http://sohowww.nascom.nasa.gov/pickoftheweek/old/19feb2002/index.html (unfortunately we missed that by a bit)

http://sohowww.nascom.nasa.gov/pickoftheweek/old/01jul2002/index.html
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
How long to solar flares last?
C.O & J.O

ANSWER:
Most flares are quite short really, less than hour. The longest flare that we've seen with the Japanese Yohkoh satellite was 12 hours though. Compared to flares on other stars though the Sun is a bit of a wimp - some of those flares are a thousand times more energetic than the Sun and can last up to 10 days!
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
Can scientists predict solar flares before they occur? If so how?
-K.R.

ANSWER:
Unfortunately not yet. This is a big challenge and one of the big goals in modern solar physics. The hope is that future instruments (both on ground and in space) will provide the necessary data to make reliable forecasts. Many scientists believe that the key will be to have reliable vector magnetic field measurements of active regions.

My personal impression is that we're about at the stage of weather forecasting 50 years ago - litte more than guesswork. Meteorology has come a long way since, so I'm optimistic that we eventually we'll crack that problem, too.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
What causes solar flares?
from Zach

ANSWER:
Solar flares occur when energy stored up in the sun's magnetic field is suddenly released, or converted from magnetic energy into heat energy and motion. The churning motions (convection) in the sun's atmosphere twist up the magnetic field -- think of it like twisting up a rubber band -- if the twisting gets too much, the magnetic field lines break and join up with much less twist (we call it "reconnect") heating up the gas in that vicinity to very high temperatures as it does so. That event is a solar flare.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

Solar Wind

QUESTION:
What is a "solar wind"? In ancient civilizations were auroras thought to be signs from their gods?

ANSWER:
The solar wind is a very small portion of the ionized atmosphere of the sun that is blown away from the sun by its tremendous temperatures.

The outer atmosphere of the sun is called the corona and its temperature is millions of degrees. So some of the atoms in the corona are moving very, very fast and can escape the sun. The surface of the sun is only about 6000 degrees, much cooler than its atmosphere.

Very perceptive, some ancient civilizations did think auroras were signs from gods. Others thought that they were light from fires burning over the horizon or from sunlight reflected off of snow on the ground.

I hadn't even seen aurora live and in person until after I had studied their effects for several years. So I knew what caused them. When I did see them for the first time, I was awed by their magnificence and beautiful colors. If I had not known what they were and saw them, by surprise, for the first time, I can't imagine what I would have thought they were! What do you think you would have thought?
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

QUESTION:
Can auroras ever be seen clearly with calm winds and inactive sun?

ANSWER:
If you mean "winds" on earth, they have nothing to do with the aurora. If you mean "solar winds", then the aurora is seen only in the polar cap. There is always aurora. When the sun is active, the solar wind is stronger and the aurora occurs more often at lower latitudes. When the sun is inactive, and the solar wind calm, the aurora occurs at high latitudes.
Chuck Deehr
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
What does solar winds feellike?

ANSWER:
I don't think anybody has experienced what it feels like. My guess would be that you don't feel it at all. The solar wind has an extremely low density, just about 1 particle per cubiccentimeter. It is very difficult (if not impossible) to create such a good vacuum here on Earth.

NASA has a mission going on called GENESIS which collects solar wind atoms with large collector arrays and then will return them to Earth in a capsule for detailed analysis. Check out:

http://genesismission.jpl.nasa.gov/
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
How long do some solar winds last???

ANSWER:
The solar wind is always blowing. There are changes in the solar wind and there are portions of it which are considered 'fast' or 'slow' but it is constantly streaming away from the Sun.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
What is solar wind,why does the sun have so many sunspots and why is the sun hot?

ANSWER:
I'll answer your questions one at a time:

The Sun is hot because of its great source of power: nuclear fusion. At the Sun's core, the pressure and temperature are great enough to cause the nuclear fusion process: hydrogen nuclei are "fused" into helium nuclei, and some of the mass involved is converted into energy. The core of the Sun is an enormous nuclear furnace, and the heat released there filters outward, making the Sun hot.

The Sun has sunspots because of powerful magnetic field activity on and under its visible surface (its "photosphere"). The motions of electrically charges gases (plasmas) in the Sun, and the Sun's rotation, generate the magnetic fields, like an electrical current generates a magnetic field in an electromagnet. Wherever strong magnetic field come out of the Sun, the hot gases that normally rise (convect) to the surface are blocked, and that spot on the photosphere becomes cooler, and appear darker than the rest of the Sun. Sunspots are visible signs of powerful magnetic "storms" on the Sun.

The solar wind is a constant flow of electrically charged particles (hydrogen and helium nuclei, electrons) and magnetic field "blown off" from the Sun through "holes" in its magnetic fields. This "wind" blows outward through the solar system in all directions, sweeping past the planets, even beyond the orbit of Pluto.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What type of effects do solar winds have on earth

ANSWER:
Most of the solar wind is deflected past the Earth by our magnetic field. The portion that does penetrate down to the atmosphere produces visible aurora, disturbances in the magnetic field, and disruptions to technological systems like satellites and long-distance electrical power transmission lines.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
What is he difference between solar winds and earth winds?

ANSWER:
Solar wind is made of plasma and magnetic field. Plasma is hot, electrically charged gas, and magnetic field is the "force" field created by moving electrical charge. Solar wind is blown off by the Sun because of intense heating of those gases.

Earth winds are motions of the gases in the Earth's atmosphere. Earth winds are powered by solar energy, just as solar wind is: sunlight heats up the Earth's surface, causing air to rise, as a hot air balloon does. Differences in atmospheric pressure caused by solar heating force air to flow from one place to another, making wind.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
How fast can the wind go? Where does it most often occur?

ANSWER:
Do you mean solar wind? If so, here's an answer: the solar wind blows past the Earth at speeds of 200 to 800 kilometers per second. Normal solar wind (maybe 200 to 400 kilometers per second speed) blows outward from the Sun in all directions, throughout the solar system. "Gusts" in the solar wind, caused by explosions (flares, coronal mass ejections) in the Sun's atmosphere and from "holes" in the Sun's magnetic field) can make the solar wind blow faster (up to and sometimes greater than) 800 kilometers per second; these gusts happen in whichever direction from the Sun the explosion or hole was pointing.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What are some major causes does the solar winds do to the Earth?

ANSWER:
I'll answer the question: What are some of the major effects of the solar wind on the Earth?

QUESTION:
Is there any other type of solar weather besides solar wind that affects the Earth in the way that the solar winds do?

ANSWER:
No, the only source of space weather that affects the earth is the solar wind, which comes from the sun, see the explanation below:

QUESTION:
How would you describe how the solar winds effect the Earth?
-K.R.

ANSWER:
The weather in space comes from the sun. The sun's atmosphere is very hot, millions of degrees, and is constantly blown away from the sun. This wind is called the solar wind. It can be very fast or very slow, very dense or not very dense. The very fast, very dense solar wind has the most effect on the planets.

QUESTION:
Are neutrinos considered solor winds, and have scientist recently found a way of finding them?
TJP

ANSWER:
Neutrinos are a result of the nuclear reactions that are continuously occurring in the sun's core. The fusion reactions, like those in a hydrogen bomb, cause nuclei to fuse (that's why they are called fusion bombs) and in addition, neutrinos are released. They travel through the outer layers of the sun, through interplanetary space and through the earth, mostly without interacting with any of those regions. Thus we can conclude that neutrinos are difficult to detect, because they don't interact very well with matter. However, scientists have known, for over 50 years how to detect them. One way is to detect the reaction of their interaction with heavy water, by searching for the reaction products in million gallon tanks of water, in mines, deep below the earth's surface.
Dr. Bill Taylor
Project Manager
Raytheon at Goddard Space Flight Center

Sounding Rockets

QUESTION:
What are you going to use the rocket for?????

ANSWER:
Scientists at Poker Flat use rockets to send different types of measuring instruments high into the atmosphere, where auroras happen. Different rockets carry different types of instruments. Some measure temperature, air composition, electrical and magnetic fields, and other things. The main reason for the rocket is to put these instruments right in the middle of the aurora.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
Why do the trucks pulling the rocket to the site back along, rather driving "forward"? Is it for traction?

ANSWER:
The trucks back up to the rocket launchers because this is the only way to position the rocket at the launcher without the truck getting in the way!
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
How Long does it take to make a rocket?

ANSWER:
That is a difficult question. I honestly don't know how long it takes to make the boosters - that is done by private companies. The payload (the instruments that the rocket carries) can take anywhere from months to years to make, depending how complex they are. Once all the parts are made, it takes a few weeks to assemble them all together and test them. So the final assembly is a matter of weeks, but the individual peices may take years to build.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
How large is the rocket?

ANSWER:
Rockets come in a variety of sizes. Sounding rockets, those used to study the aurora, vary in size from the single-stage Super Arcas which stands 7-feet (3 meters) high to the four-stage Black Brant XII which stands at 65-feet (20 meters) tall. These rockets can carry scientific payloads of various weights to altitudes from 30 miles (48 km) to more than 800 miles (1,287 km).

To learn more about rockets, see this web page:

http://spacelink.nasa.gov/Instructional.Materials/NASA.Educational.Products/Rockets/
Dr. Laura Peticolas
Space Science Laboratory at UC Berkeley

QUESTION:
How many types of sounding rockets are there?
-D.S. & B.C.

ANSWER:
NASA's sounding rocket program handbook lists 14 rocket types that are currently available for supporting scientific research. Over the years, many other rocket types have been used, both in the US and overseas. Different rocket types can be made by attaching the different booster types in different combinations. So there are probably hundreds of possibilities but, as I said, NASA has focused on just 14 for its current program.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
How Long does it take to make a rocket?

ANSWER:
Building a rocket doesn't take too long, maybe six months or a year or so, but we don't usually fly rockets by themselves, or empty. Usually we use a rocket tolaunch a satellite. A satellite, with all its complex scientific experiments or telecommunication or other gear in the payload compartment of the rocketmay very well take years to build. The last satellite experiment my group launched was started into its design phase in 1987 and was launched in 1995. It's still operating in orbit now. It is called SOHO. You can see pictures of it on the Web if you go to the address:

http://sohowww.nascom.nasa.gov

On that web site you can see pictures of the Atlas rocket we used to launch SOHO, plus pictures of the SOHO satellite itself AND lots of beautiful pictures of the Sun and its corona - and even movies of solar explosions!
Dr. Don Michels
Naval Research Laboratory

Space Weather

QUESTION:
Do you think the public is adequately informed on the impacts of space weather on us here on earth? What would you like to see happen in order for the public to be more informed, if your answer is no?

ANSWER:
No, unfortunately not. I think it's only very recently that the media have started to pay attention to this, perhaps thanks to the dramatic imagery from SOHO and other related space missions. I believe that spaceweather would be an ideal topic for science classes at schools. Kids would not only learn about this important topic, spaceweather also provides an ideal "hook" for introducing important basics concepts such a magnetism or the working of our daylight star (and thus an entry into basic astronomy).

A very nice introduction into SpaceWeather is available at:
http://www.windows.ucar.edu/spaceweather/basic_facts.html
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
What kind of weather is there in space? Does it affect the planets?

QUESTION:
What type of energy or storms we receive from the sun are harmful?
from:SJR

ANSWER:
The most harmful energy or storms from the sun are solar proton events. They occur associated with large coronal mass ejections. Protons are accelerated to extremely high energy, and, threfore, can penetrate through a lot of material. For human travel to other planets, this is the most worrisome kind of radiation that could be encountered.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
What other type of weather besides what happens on the sun occurs in space?

ANSWER:
Space weather is caused only by the sun and the solar wind, as described below:

Sun

QUESTION:
Why do the planets in our solar system rotate and revolve around the sun at different speeds?

ANSWER:
Hi!

A very good question. It's actually two very different qiestions. Planets revolve around the sun at different speeds because of the way that bodies are forced to move in a gravitational field which decreases in strength the farther from the sun that they are. Objects closer in, have to move faster than more distant planets. They rotate at different times for reasons we don't fully understand right now, but it seems this has to do with exactly how they were formed (by collisions with large bodies). Each collision causes the forming planet to get speeded up or slowed down, so the final speed depends on a complicated sequence of impacts with bodies of various masses just before the planet has formed. So, we understand why the 'years' are different, but we dont completely understand why the 'days' are different.
Dr. Sten Odenwald
Solar Astronomer
NASA Goddard Space Flight Center

QUESTION:
What is solar Energy? And how does the sun get many sunspots,are they just cool spots on the sun that don't have enough gas to burn?:)*

ANSWER:
When we say "solar energy" we generally mean the energy from the Sun that we can use on Earth. Solar energy makes plants grow and evaporates water so that it can fall again as rain. It also warms the land, that heats the air, that makes the wind blow, another form of solar energy.

The Sun's energy source is deep in its core, nuclear fusion, where four Hydrogen atoms join nuclei to become one Helium atom, releasing energy. That energy bubbles up from deep in the sun to the surface, where most of it leaves in the form of light energy. The sun doesn't "burn" in the sense we think about... fuel combining with oxygen to get heat and light. Instead the fuel is nuclear energy.

Sunspots are cool areas on the sun, where the magnetic fields are very strong. Since it is cooler it looks darker to us but it is still very very hot!
Dr. Patricia Reiff
Rice University

QUESTION:
What is a revolution of the sun?

ANSWER:
"Revolution" and "rotation" are two different types of motion. When an object moves around another object (like Earth going around the Sun or a tetherball going around its pole), it is "revolving." When an object spins (like Earth spinning on its axis), it is "rotating."

The Sun rotates on its own axis, like Earth. Unlike Earth, the Sun is a gaseous object, not a solid one. Because it is fluid, the Sun does not rotate like a rigid sphere; instead, its equator actually rotates faster than its poles. It takes about 28 days for the Sun's equator to rotate once; about 32 degrees for the poles.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
Why do the planets in our solar system rotate and revolve around the sun at different speeds?

ANSWER:
The planets orbit (revolve) around the Sun at different speeds because at their different distances from the Sun, the Sun's gravitational pull is different: the farther from the Sun, the weaker its gravitational tug on the planets and other objects. The stronger the Sun's gravitational pull on a planet, the faster that planet has to move to avoid falling into the Sun.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
How hot is the sun as you know it and how round is the sun

ANSWER:
The sun's surface is about 5800 degrees Celsius. Sunspots are around 4800 degrees Celsius. The Corona is several million degrees!

The Sun is not quite round. Because it is spinning (27 days), the distance around the equator is a little larger than the distance from pole to pole across the equator, but only by a small amount.
Dr. Patricia Reiff
Rice University

QUESTION:
Why do scientists refer to the sun as a solid surface when its really a gas?

ANSWER:
It's true, it is a gas, but the density suddenly drops when you reach the photosphere, and light can easy leave. That level, where the bulk of light comes from, is called the photosphere. In visible light you can't see under the photosphere.

The corona above it is "optically thin" (you can see through it).
Dr. Patricia Reiff
Rice University

QUESTION:
How do you determine where the layers of the sun begin and end?

ANSWER:
In the inside of the Sun, the layers are determined by the way energy moves: by conduction in the core, by radiation in the next layer, and by convection (bubbling) in the outermost layer. Then we hit the "photosphere", where the energy leaves the Sun in by means of visible light.
Dr. Patricia Reiff
Rice University

QUESTION:
What is the kp solar activity and what relationship does it have with the Auroras?

ANSWER:
The kp solar activity is a number that comes from magnetic measurements made on Earth at lower latitudes (for example in the United States and in Europe). Earth has its own magnetic field, but magnetic fields can also come from moving charged particles (like electrons and protons). The KP index number comes from magnetic fields made by electrons and protons which circle Earth very far away (about 36,000 km away from the surface of Earth). Sometimes the solar wind will interact with Earth's intrinsic magnetic field which then influences how many particles are circling Earth as well as how fast these particle circle Earth. This interaction changes the magnetic signature on Earth and thus changes the KP index. Often the particles that circle Earth were also involved in the process that creates the aurora. Also the interaction of the solar wind with Earth's intrinsic magnetic field will result in more aurora. And so indirectly the KP index is related to the aurora.
Dr. Laura Peticolas
Space Science Laboratory at UC Berkeley

QUESTION:
Besides the Earth, does the sun have any other effects on other planets when there are solar flares, prominences, or winds?

ANSWER:
Yes, we recently published a paper on "Space Weather on Mercury". Venus and Mars don't have magnetic fields, but solar activity can cause heating of their upper atmospheres and extra ionization of their ionospheres.

And, of course, the Sun has major effects on comets and their tails!
Dr. Patricia Reiff
Rice University

QUESTION:
Can the sun burn any of the planets?

ANSWER:
It won't catch them on fire, but it does affect the atmospheres of the planets, heating them up.

The Sun's activity has had a major effect on the atmospheres of Venus and Mars, sweeping away their water! They used to have a lot of water on their surface, but the Sun's ray's ionized their hydrogen and the solar wind swept it away. They didn't have a protective magnetic field like we do!
Dr. Patricia Reiff
Rice University

QUESTION:
Is it possible for scientists to predict any solar storms on the sun?

ANSWER:
As scientists learn more about how the Sun behaves, we are getting better about being able to predict solar activity. For example, from observations of the number of sunspots over the years (centuries, actually), we know that the solar magnetic activity changes in a cycle that's usually about 11 years long; we can use this knowledge to predict with some certainty when the Sun will be more likely to be "stormy" or active and when it will be more calm.

Watching sunspots and magnetically active regions on the Sun, scientists see how they form, grow, evolve, and fade away, and are beginning to learn the patterns of activity that lead up to solar "storms." We can observe flares and other eruptions on the Sun, see which way they are headed, and so predict whether or not this space weather will impact the Earth. Between a flare and when its effects would arrive at Earth there is usually about a 4 day space.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
Have any solar storms or Solar winds occured iin the last month, if so how many, and how long did they last?

ANSWER:
The last month has been relatively quiet on the Sun. There have been hardly any big flares....except for the last two days, in which there have been two very big flares! There have been plenty of sunspots of course, and most of these last several months.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
What is the kp solar activity and what relationship does it have with the Auroras ?

ANSWER:
Kp is not a solar parameter. It is called the "planetary index," and is an index used to describe fluctuations in the Earth's magnetic field. Kp starts with an index "K" that describes the average, over three-hour intervals, of Earth's magnetic field strength and direction, as measured at a number of geophysical observatories located in various places over the Earth's surface. So, each observatory comes up with a K value for a particular three-hour interval. Then Kp is computed as an average of all the local K values. Kp=9 means "very active." Kp=0 means "very quiet."

Kp gives a good idea of how active or quiet Earth's magnetic field is at a given time. This is, however, related to the Sun in that disturbances in Earth's magnetic field are caused by disturbances in the "solar wind," a very thin, electrically active gas that boils off the Sun, and washes continually over the Earth and its magnetic field. When the solar wind is quiet, Earth's magnetosphere tends to be quiet too - hence not very exciting auroras, because auroras occur when the Kp index is high. When the Sun is active and great solar storms send out shock waves into the solar wind, there is a chance that such waves will impact Earth's magnetosphere. Then bright, dramatic auroras occur!
Dr. Don Michels
Naval Research Laboratory

QUESTION:
Once the scientist get a hold of neutrinos what will they be used for?
From:SJR

ANSWER:
I do not think that scientists will be able to trap or contain neutrinos in the foreseeable future. However, we can detect their passage, and this gives information about their sources - on the Sun, for example.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
Is there a pattern for when storms on the sun occur?

ANSWER:
That's a great question, and the answer is "YES!" There is indeed a pattern, though no one fully understands what causes it. The pattern is called the "eleven-year sunspot cycle." Try this: Observe the Sun every sunny day with some instrument that projects an IMAGE ON A WHITE PAPER (NEVER look at the Sun directly with your eye! - it can blind you!!) Use a paper with a circle on it about the size of your solar image. Then make a pencil mark for every place where you can see a sunspot, and write down the number of sunspots you observe. Do this every day for a year or so, then look at all your data. You will see that the number of sunspots varies a lot from day to day and week to week. If you have enough pattience to do this for 10 or 20 years (which scientists do - although they do other things like ball games and concerts in between!) you will notice that your sunspot numbers are all over the place. But if you start doing averages of the numbers for every three-month interval (i.e. do an average of this month, last month, and next month) and do that every month for decades, you will see that these average numbers go very low, almost zero, at one period, then increase over the next four years to a pretty high number (maybe a hundred or more if your images are good enough!) and then decline again over the next seven years. Then it repeats again, in a low-high-low cycle of approximately eleven years. If you're in too much of a hurry for this, you can search the Web for sunspot numbers (try NOAA.gov) and let someone else do the counting - but then you miss the fun!!

NOW THE PUNCH LINE - When you see lots sunspots you can be sure there are lots of solar storms, when no sunspots - no solar storms, or not many. Therefore: lots of sunspots -> lots of solar storms -> lots of auroras (and some at low latitudes, when the storms are big ones.) I know it's asking a lot, but this IS an experiment you can do YOURSELF!
Dr. Don Michels
Naval Research Laboratory

QUESTION:
Neutrinos are discovered by what process?
From:SJR

ANSWER:
Neutrinos were first discovered theoretically. They are very hard to observe, since they can pass through almost anything without colliding, but they have now been observed in huge tanks of cleaning fluid!
Dr. Patricia Reiff
Rice University

QUESTION:
How high did the biggest prominence go and when? Did you give it a name?

ANSWER:
The biggest prominence I have seen an image of that didn't leave the sun permanently was during SkyLab, where it went up nearly half the Sun's radius over the Sun's surface.

But Coronal Mass Ejections are like super-prominences that "let go"of the sun and go out into distant space, long past the orbits of Jupiter and Saturn! When they pass Earth, they can cause "space weather".

We generally don't give them a name, but we might call it by the date of the storm it caused on Earth, like the "Bastille Day storm" or the "great storm of August 1972".
Dr. Patricia Reiff
Rice University

QUESTION:
What nebula did the sun form in?

ANSWER:
Unfortunately, your question was assigned to someone who knows nothing about this subject, and I have no capability of informing the administrator of this activity of this fact. Perhaps you could resubmit it.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

Sunspots

QUESTION:
Does sunspots effect the earth and us?

ANSWER:
Yes, sunspots can affect the Earth in two ways. First, when there are alot of sunspots, the Sun outputs more energy then when there are no sunspots. So Earth gets slightly more solar radiation when sunspots are present. But also, if a Sunspot sports very complex magnetic fields, then these fields can trigger a solar flare which is a huge release of energy which can send energetic particles towards Earth. These energetic particles can flood parts of the magnetic fields in the earth's atmosphere and cause power outages.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
About how many years will it take for sunspots to make the sun completely black out? Explain why and how.

ANSWER:
Individual sunspots come and go -- a typical sunspot lasts from several days to a few weeks. The total number of sunspots at one time on the sun varies on an eleven year timeframe, from there being many (dozens) which we call solar maximum, to there being one or two, or, occasionally, none at all (solar minimum). Even at solar maximum sunspots cover only a few percent of the sun's surface, and do little to change the sun's total brightness, as the sun compensates by becoming a little brighter in the areas around sunspots (the energy has to come out somewhere). So Sunspots will never completely black out the sun.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
Does sunspots effect the earth and us?

ANSWER:
Yes, but indirectly. Sunspots do not affect most of the energy that the sun radiates to the earth, that is, the sunlight we see. Fortunately for us, this radiation does not change much. However, the number of sunspots is an indication of the general level of magnetic activity on the sun. This affects other radiations from the sun that we cannot see without special sensors. These radiations can vary a lot. The effects of these radiations on the upper atmosphere, the earth's ionosphere and space around the earth are called space weather. As human activities become more complex and depend more on communications and accurate navigation, space weather will more and more affect our activities on earth.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
Does sunspots afffect the Earth and the creatures living on earth?

ANSWER:
Sunspots have little or no known effect on life at the surface of the Earth. This is because the atmosphere is thick enough to block any electromagnetic or particulate radiation emitted by the Sun's active regions. However, large flares associated with these regions can generate proton radiation that penetrates deeply enough into the atmosphere to expose high-flying aircraft passengers to doses comparable to a chest X-ray. Also, eruptions from these regions do disrupt technological systems like satellites and long distance electrical power lines.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
What are sunspots, how do they form, where on the sun do they form, and how hot are they?

ANSWER:
Sunspots are dark areas of irregular shape on the surface of the Sun. Sunspots are darker than the rest of the visible solar surface because they are cooler: Most of the visible surface of the Sun has a temperature of about 5400 C, but in a big sunspot the temperature can drop to about 4000 C. Sunspots come in sizes between about 2500 km and about 50,000 km. They are cuased by twisted knots in the Sun's magnetic fields. The twisting of the magnetic field is caused because different parts of the Sun rotate at different speeds.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
Do sunspots change the tempeature of the sun, if so,why and how?

ANSWER:
Sunspots appear dark because they are somewhat cooler than the rest of the sun's surface (this is relative -- the sun's surface temperature is about 5700 degrees, sunspots are about 4500 degrees -- still very hot by ordinary standards). The hotter something is the brighter it glows, hence, in comparison, sunspots look dark.

Sunspots are regions where strong magnetic fields come out of (or go into) the sun. The strong field limits the motion of the gas, so it can't convect (churn around like water in a boiling pot) and bring heat up from below as happens everywhere else on the sun's surface. Hence sunspots are cooler.

Globally the sun compensates, as the heat as to escape somewhere. Regions around sunspots are a little hotter and hence a little brighter than the rest of the sun, but this effect is too subtle to see in a photograph of the sun.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
How do sunspots form and are the interesting to reasearch?

ANSWER:
Sunspots are places on the Sun's photosphere (its visible surface) that are cooler than normal (only about 3000 or 4000 Kelvins instead of the normal 6000 Kelvins). Being cooler, they appear darker. These "not-so-hot-spots" are formed where strong magnetic fields emerge from inside the Sun; these magnetic fields prevent the normal rising of hot, convecting gases from inside the Sun, and so less heat from within the Sun reaches that spot.

Sunspots are very interesting to research. First, they are examples of enormous and powerful magnetic fields, much larger and stronger than anything on Earth. Scientists can study them to see how huge magnetic fields affect plasmas (electrically charged gases).

Second, the number and size of sunspots on the Sun indicates how magnetically active the Sun is at a given time. People have been obseving sunspots for many centuries--and in the last four hundred years detailed studies of the number, shapes, and life-time of sunspots have been made.

We have learned that the number of sunspots, and thus the magnetic activity of the Sun, changes in a cycle that typically lasts about 11 years. There is also evidence that this cycle of solar activity change may affect the climate on Earth, amongst other things.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What is the average amount of sunspots on the sun's surface at one time?

ANSWER:
There is no single number that is a good average, because the number of sunspots varies in an 11-year cycle. It also depends on how you count individual spots versus groups of spots. By the usual methods, the sunspot number varies from as few as zero at minimum activity up to as many as 200 in the most active cycles. However, a "typical" solar cycle would produce only around 100 spots on the sun at its peak.
Mark Conde
Assistant Professor of Physics
Geophysical Institute of the University of Alaska Fairbanks

QUESTION:
How many sunspots have you recorded on the sun?

ANSWER:
Scientists first started observing sunspots in the early 1600's. It took time before they noticed that there was something called an 11 year 'sunspot cycle'. This means that, for example, in 1995 there were times when no sunspots were on the sun. Then in 2000 the sun was crowded with sunspots - sometimes 25 sunspots were on the sun at one time! The number of sunspots goes up and down over an 11 year period. Personally, I've only studied about a dozen sunspots in detail, but I check the internet daily to see what the sun looks like today and I've seen hundreds of sunspots over the years.
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
Why do sunspots increase and decrease in regular 11-year cycles and what would happen if they didnt?

ANSWER:
Sunspots are a visible signature of the sun's magnetic field. They mark regions where strong magnetic fields either come out of or go back into the sun. THe Sun's magnetic field is generated in the region just below the surface called the convection zone where the gas churns around (convects) bringing heat up from below. We don't really know why this region builds up the field and then reverses it every eleven years -- using helioseismolgy we've monitored this region for not quite a solar cycle, so our understanding is improving.

We do know that in the 17th century (from about 1620 to 1700) the sun had very few sunspots and didn't have an eleven year cycle; the 11 year cycle has been observed since about 1720. So the sun can behave in different ways. Why? I wish I knew.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University

QUESTION:
How big is the biggest sunspot???

ANSWER:
Sunspots have been appearing and disappearing on the Sun for most of the Sun's lifetime (almost 5 billion years), so it's impossible to say how big the biggest sunspot was. In the last couple of years, there have been sunspots more than 15 Earth diameters across--over 120,000 miles across! Even "normal" or typical sunspots are about the size of the Earth.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
About how many years will it take for sunspots to make the sun completely black out? Explain why and how.

ANSWER:
That is a very unlikely scenario. Sunspots live for just a few weeks before they dissolve.

The number of sunspots varies with the solar cycle. During solar minima, there are usually only a few sunspots on the solar surface. During maximum there are many. To understand the solar dynamo (the mechanism that produces the magnetic field in the Sun) is one of the big quests in modern solar physics.

More info about sunspots under:

http://science.nasa.gov/ssl/pad/solar/sunspots.htm
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
Do sunspots change the tempeature of the sun, if so,why and how?

ANSWER:
Yes. Sunspots are cooler areas of the surface of the sun (photosphere) by 1000 to 1500 degrees Celsius out of about 5,800 degrees. That is why they look dark. They still are not cool. The areas of sunspots have extra strong magnetic fields. We think that the magnetic fields bring up the hot solar gases from below the surface.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
Do sunspots change the tempeature of the sun, if so,why and how?

ANSWER:
Very good question! Yes, but the exact process is not completely understood yet.

The magnetic field of sunspots inhibits energy transport from the interior of the Sun. Sunspots are therefore cooler, and consequently darker.

The Sun gets a little darker when there is a big sunspot (up to 0.1%). One would therefore expect that during activity maximum, when there are many sunspots, the Sun is a little darker. But the opposite is true! The Sun actually is a little brighter during activity maximum (also about 0.1%).

See http://www.pmodwrc.ch/tsi/composite/pics/comp_d25_05_0301.png for a plot of the total solar irradiance over the last 24 years. The sharp "needles" are sunspots crossing the disk.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
Whats the record for the most sunspots on the sun at once?

MJCZ

ANSWER:
When scientists make a count of sunspots each day, they are only counting the ones on the side of the Sun facing us at the time. They have methods and formulas for counting sunspots to come up with a number. By an official count, the number of sunpots seen at a given moment can be as high as 100 to 200 sunspots. Numbers like this usually happen round "solar maximum," the peak of solar magnetic activity that occurs every 11 years. At other times, the counts can be much lower.

As for the "record" number of sunspots, that count was made in 1957 for an annually averaged number of 201 sunspots.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
What was the most amount of sunspots that ever occured and what was the size of the largest sunspot?

ANSWER:
Wow. These are hard questions. I don't know the exact number of the most sunspots ever - I would guess it to be about 25. (Remember we only see half of the sun at any given time so the total number of sunspots on the sun might be 50). The biggest sunspot in the last ten years was present on March 29, 2001 (Sunspot #9393) and it was 13 times the size of Earth. I don't know the answer to how large was the largest sunspot ever - I only know the answer for the last ten years. Thanks for asking your fun questions!
Aimee Norton
Solar Astronomer
National Center for Atmospheric Research in Boulder Colorado

QUESTION:
What kind of tools do you use to find sunspots?

ANSWER:
Sunspots are easy to see (but NEVER try to look directly at the sun to try to see them. You only need simple tools.

What is best is to obtain a small telescope. Point it at the sun and place a piece of stiff white paper where the image is focused. Ths sunspots will show up as dark spots.
Dr. Bob Hoffman
NASA Goddard Space Flight Center

QUESTION:
What was the most amout of sunspots that ever occured and what was the size of the largest sunspot?

ANSWER:
The most active 11-year solar cycle on record is cycle 19, which reached a monthly averaged sunspot number of over 250 in the end of 1957 (note that groups enter this number with a multiplicator of 10). Compare this with this cycle, which just went a little over 150.

More info and graphics under:

http://science.nasa.gov/ssl/pad/solar/sunspots.htm

and

http://sidc.oma.be/html/sidc_graphics.html

The largest sunspot group in the last 9 years is pictured at:

http://sohowww.nascom.nasa.gov/hotshots/2000_09_22/

It occurred in September 2000 in Active Region 9169. It covered an area a thirteen times larger than the surface of the Earth!

The size of the absolute largest sunspot I don't know. I would have to look that up. But certainly not much bigger than the one described above.
Dr. Bernhard Fleck
SOHO Project Scientist
European Space Agency
Research and Scientific Support Department

QUESTION:
What causes sunspots?
from Jaron

ANSWER:
Sunspots are places on the Sun's visible surface (its photosphere) where powerful magnetic fields are emerging from inside the Sun, and from which they continue upward into the Sun's atmosphere. The magnetic force of these fields stop the normal upward rising of hot gases from inside the Sun, so less heat reaches the surface in these spots. Less heat means cooler, cooler means darker. Sunspots are only 3000 to 4000 Kelvins in temperature, while the rest of the Sun's surface is about 6000 Kelvins.
Mr. Ben Burress
Science Content Developer
Chabot Space & Science Center

QUESTION:
About how many years will it take for sunspots to make the sun blank out?

ANSWER:
An individual sunspot lasts anywhere from several days to a few weeks, then the strong magnetic field that causes the sunspot difuses away into the general, much weaker solar field and the spot disappears. The number of spots on the sun at any one time varies from perhaps 50 or so at solar maximum, to one or two, or even none at solar minimum, on an 11 year cycle. But even at maximum the total area of the sun covered by spots is 1 or 2%. Spots will never blank out the Sun. Furthermore, sunspots are not dark, just darker than the rest of the sun. They have a temp of about 4500 degrees as opposed to the rest of the sun which has a temp of about 5700 dgrees. A 4500 degree object glows pretty brightly.
Dr. Jeffrey Hughes
Professor of Astronomy
Boston University