"To The Max" ON-AIR FAQ

ASTRONOMY   BIG BANG THEORY   CME (CORONAL MASS EJECTIONS)
COMPOSITION OF THE SUN   CORONA   FLARES   LIFE CYCLE OF THE STARS
MAGNETISM   OZONE   ROCKETS   SATELLITES   SOLAR CYCLE   SOLAR MAXIMUM
SOLAR OBSERVATORY   SOLAR PHYSICIST   STARS  SUN   TEMPERATURE OF THE SUN

QUESTION:
How much money are astronomers paid? What are the necessary prerequisites to become an astronomer of the sun? What other scientific fields do the space scientists study in order to work on the sun? from Andy/per 5

The salary of an astronomer depends on where they work. In a University, the range is \$25,000 at the start up towards \$80,000. In industry, it can be twice that, and yes, there are astronomers in industry, for example, Lockheed-Martin. However, virtually every astronomer I know would probably happily work for nothing because we love it! To become an astronomer of any sort, you first must learn physics, and this also requires mathematics through advanced calculus. You also need to know as much as possible about computers. Other helpful fields are electronics and optics.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

QUESTION:
Do you believe in the "Big Bang Theory"? If not, what is your hypothesis? Could you please explain a little bit of it to us? from Team 6/per 3 McQuone

I think that the Big Bang theory is probably correct. We have evidence that there was a massive explosion at the beginning of the expansion of the universe. This evidence is known as the 3-degree background radiation, and it was detected using a radio telescope built at Bell labs. This telescope measured a very small radio signal that appeared to come from every direction in the sky. Calculations showed it could be explained by assuming that outer space has an average temperature of 3 degrees above absolute zero, or about 457 degrees below zero Fahrenheit. This, in turn, is the temperature you would get if there was a Big Bang 15 billion years ago and the universe was still cooling off from the explosion.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

CME (CORONAL MASS EJECTION)

QUESTION:
Will Y2K possibly interfere with the tracking of CMEs? And if it does can that cause even more trouble? Kalee

Hello Kalee! Y2K won't bother us too much, unless all our checking to be sure that our software works wasn't thorough enough. However, even if there is a problem, we should be able to fix it rather quickly. All of us at NASA (especially those who work with computers) think that the Y2K hype is far too overinflated! If our computers have problems, we'll have to fix them, but after that we'll be back to tracking CMEs right away! Hopefully there won't be any big ones right at midnight on New Year's Day! Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

QUESTION:
How many CMEs come off the Sun every day? Sean

Sean - currently we're getting about 5 CMEs per day, hopefully more! We hope you're interested in watching the CMEs with us as we get toward solar maximum. Day to day, the number of CMEs varies a lot. During solar minimum, the average number of CMEs per day is only 1-2. Sometimes there are none, some days there are more, but on average just a few. If there is a region on the Sun which is really active, it can produce a lot of eruptions. Right now, we're closer to solar maximum, so we are dealing with a lot more CMEs. Today we've already had four! We'll probably get quite a few more by the end of the day. During solar maximum, we can get up to 10 CMEs per day - can you imagine keeping track of all of them?? Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

QUESTION:
Brad Portnoy in Mike Reynolds' class at Cranbrook MS wants to know What is in a CME and what causes them?

Hello Brad! What is a CME and what causes them? What a question! We've spent a lot of time trying to understand them. Fortunately, the people who studied these things when they were first discovered came up with a very good name for them: coronal mass ejections. They are the ejection of mass from the Sun's corona or atmosphere. They can contain a billion tons of solar material (mostly hydrogen) and can go several million miles of hour out into space. As to the cause of CMEs, there are several possibilities: they all have to do with the storage and release of magnetic energy. Most of us believe that the magnetic energy builds up, and eventually the release of this energy occurs (like a sneeze!). Sometimes the release of energy occurs as a flare (so it causes a temporarily bright energized region on the Sun) and sometimes the magnetic fields are ejected in the form of a CME. Thanks for your questions! Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

COMPOSITION OF THE SUN

QUESTION:
Since the Sun is made up of gases would anything ever be able to go through it?

The gases that the Sun is made of are very hot, and the pressure at the center is enormous. Nothing would be able to survive inside the Sun.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

CORONA

QUESTION:
How is the corona *really* heated? Lots of news releases have indicated that the magnetic field is doing it, but it's not clear that reconnection can do the job. For example, evolution of a potential magnetic field doesn't release *any* energy at all!

I wish I knew!! ;-) Seriously, we have some hypotheses [ a.k.a. guesses, or suspicions ] but no clear answers. 30 years ago everyone thought that the corona was heated by sounds waves, generated by the bubbling near the surface, that "crashed" up in the corona where the density of matter decreases, rather like water waves crashing on the beach as the depth of the water gets shallower. That doesn't appear to work - the energy "crashes" before it gets up into the corona. We know just from the beautiful loops that we see in the corona, that magnetic fields exist there, and that they are constantly changing. Magnetic fields can store more than enough energy to head the corona, but how it gets released involves a bit of "hand waving" at the present in my humble opinion. As you say just moving a field around doesn't do anything. A magnetic field is just a way of describing an electric current that is flowing somewhere, and the dissipation of that current - the "light bulb" if you will - still needs to be understood. So, it's a mystery - for now. BUT, I'm confidant that we'll understand it some day soon, that's the fun of science. There are oodles of questions, and we're making good progress answering some of them, and asking even more along the way!!

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

FLARES

QUESTION:
Can the sun's fire really be fire? because fire needs air to burn. Raymond Age 8

The sun is made of really hot gas, so hot that the atoms it's made of have lost some of their electrons. This kind of matter is called plasma. The plasma on the sun, because it is so hot, releases energy we can see (visible light) and energy we can't see (radio, ultraviolet, infrared, X-rays, and gamma-ray light). So the sun is not really "burning" in the sense that we think of when we watch a fire burn. When wood burns, in part it's changing from a solid into a plasma and needs air to do so. In the sun, there are no solids! So the two processes are actually quite different, even though they look the same to us in pictures.

SCIENTIST: Elizabeth Newton, NASA Marshall Space Flight Center

QUESTION:
How will the solar flares, clouds and radiation affect the satellites during solar maximum? What can be done to prevent damage? Will particles directly hit people? from Team 4/McQuone

Hello Team 4 - First I must applaud the way you phrased the question, because you mentioned solar flares, clouds, and radiation - all are important, and we must consider all of them when we begin our "preparations" for solar maximum. We primarily worry about energetic particles - these can come from solar flares (from the sun) or they can come from magnetic clouds (the clouds can impact earth and cause the particles to become energized). These can affect spacecraft components in a number of ways. First, if the electronic components become too highly charged by these particles, they can damage the components. There are some cases where the charge became so high that it destroyed the power supply! Also, energetic particles, when hit memory storage devices, can "flip bits" and cause "artificial memory problems." To prepare for these, we monitor spacecraft charging more closely, and we write software which looks harder for inconsistencies which might be flipped bits. As for radiation - it's quite fascinating what it can do - if we get a large increase in energetic light, it can cause the atmosphere to expand and increase the drag on spacecraft. During a few cases, more than a thousand spacecraft were "lost" because all the extra drag caused the tracking programs to be unable to follow them. To prepare for this, we have to enable the tracking programs to be ready for sudden slow-ups! There are a lot more things we do in space to prepare for solar max - including monitor the sun more closely. I hope you'll do that with us! Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

QUESTION:
Can the sun create a solar flare that is so big that it could reach or engulf the earth? from Team 2/ per 5

There is no evidence that the Sun has flares that are large enough to effect life on Earth. Other stars similar to the Sun have "Superflares" but they appear to be caused by a Jupiter class planet really close to those stars. The Earth's atmosphere and magnetic field are very good shields. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
Could the impact of the solar flares on the earth once have been so great that it caused the destruction of the dinosaurs? from April, Kristy, Kelly and Jessica S./per 7

The Earth's magnetic field and atmosphere are very good shields. There is no evidence that any solar flare has been severe enough to effect life on Earth. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
Has a solar flare ever been large enough to affect the heating of Earth?

No, in terms of heat (thermal energy) flares don't have enough to affect the Earth's temperature. The amount of extra heat that comes out of the Sun due to a flare is really pretty miniscule compared to what the Sun puts out on a regular basis.

SCIENTIST: Elizabeth Newton, NASA Marshall Space Flight Center

QUESTION:
How long can a solar flare last? Lauren

A solar flare can be as quick as a few seconds, or as long as thousands of seconds! That's a pretty big dynamic range. It's a big mystery why some are so fast, while others are so long.

SCIENTIST: Elizabeth Newton, NASA Marshall Space Flight Center

QUESTION:
We know that the solar flares will probably affect satellites, but is it possible for particles from solar flares to make it through the atmosphere to affect us? from Brittany, Jermaine, Gina, and Meghan per 7

Hi gang! A very small number of particles from solar flares reach Earth, and most scientists do not believe there is any additional danger to us from flare particles during solar maximum - there just aren't enough to be dangerous. People in airplanes can be exposed more to the particles, because they don't have as much of the atmosphere to shield them. However, the absolute worst dosage they can receive from a solar flare is no more severe than a chest X-ray. Therefore, the primary effects of these energetic particles reach us through other processes. They can cause magnetic activity which *can* be noticed at Earth. Still, it is important to research the solar flare particles - they can cause all sorts of effects, and they're very important to astronauts! I hope you're interested enough to keep watching the Sun through the school year. Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

LIFE CYCLE OF THE STARS

QUESTION:
At what point in the 5 billion years of the life of the sun will life as we know it on earth change? How will it change? from Marquis/ per 4 McQuone If the sun blows up, could people live elsewhere in the universe? from Travis/per 4 McQuone

Actually, we think that the Sun is already nearly 5 billion years old, and that it will live for another 5 billion making a total lifetime of 10 billion years. Our models predict that about 5 billion years from now, the Sun will have burnt more than 50% of the hydrogen fuel in its core. At that time, it will contract rapidly as the weight of the outer layers will no longer be supported by the pressure of the heat in the core. The Sun will shrink in size by about 15% over a few days, and then the temperature in the core will rise to where helium can be burned. Now, helium burns at a much higher temperature than hydrogen, so the pressure in the core of the Sun will increase, and the Sun will expand enormously. It will expand so much that all of the planets out to Mars will be under its surface. At that point, life on Earth would cease. People might be living elsewhere if they were able to find and travel to another planet that could support them.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
What will happen to the planets during the sun's cycle? from Caitlin/ per 4 McQuone

The Sun will expand so much that all of the planets out to Mars will be under its surface. At that point, life on Earth would cease. People might be living elsewhere if they were able to find and travel to another planet that could support them.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
How do scientists determine how long the sun will exist? from Matt/ per 3 McQuone

We determine how long the Sun (and any star) will exist by making models of it in a computer. We use physics and math to calculate various quantities that describe the conditions of the matter and energy as we go from the very center of the star to the outside. Some of these quantities are temperature, density, and composition (what the matter is made of). We can match the model to things we can observe about the Sun and other stars, like how hot their surface is and how big they are. We can then watch how these model stars change in the computer as the hydrogen is burned and converted into helium and other elements. This lets us predict the future of the Sun.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
Do you think the prediction of the sun going out in 5 billion years could be wrong? Do you think it could end any time soon? I was just wondering because a lot of predictions can go either way, right or wrong? from Josh/per 4 McQuone

We may be off by 10% (500 million out of 5 billion), but don't worry about this one. It won't happen for a very long time. We can now check our models thanks to helioseismology, the study of the sound inside the Sun. The models are pretty good.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
Is it possible for the sun to become a black hole? If so, could it suck in the earth? from Daniel/per 2 McQuone

The sun cannot become a black hole because it does not have enough mass. The sun will end its life as a white dwarf.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

MAGNETISM

QUESTION:
One video showed how the sun affects the earth's magnetic field. Can it ever breakthrough the atmosphere and affect me directly? from Scott., Jennifer, Eddie and Deepthi/per 1 McQuone

I'm guessing that your question concerns the charged electrical particles from the Sun rather than the heat and light. The lowest altitude that solar wind particles can reach is about 25 miles, well above the ground and the altitude at which passenger jets fly. When these particles do hit the Earth's atmosphere, they create the Aurora Borealis and Australis about 60 to 80 miles up in the atmosphere.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
Seeing that the sun is a magnetic star, if a giant magnet was put out in space, would the sun be attracted to it? from India, ENiola. Cpette. Steven per 1/McQuone

Yes, although it would take a REALLY big magnet, in other words, one with a mass comparable to that of the sun. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
If we did not have magnetic poles blocking the Solar Winds of the sun, what would result? from PJ/per 5

Hi PJ! That's a question that isn't just exciting to ask, but it's also important. When people talk about visiting other planets and spending extended periods in space, they consider the possibility of having energetic radiation hitting them without the protection of the Earth's magnetic fields. Astronauts wear radiation monitors which keep track of how much exposure they're getting - when they've gotten too much exposure, they have to retire, or they're under too much risk of developing cancer. We'd certainly be in the same situation without the Earth's magnetic field, though the Earth's atmosphere helps shield us as well. However, if the Earth's atmosphere has to observe *all* of the energetic particles, it can heat it so much that the Earth's atmosphere could expand out to space and partially disappear! So would we have worse trouble without having an atmosphere or because of additional radiation? Take care! Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

OZONE

QUESTION:
Does the sun effect our ozone layer and can the ozone layer be wiped out totally? from Erick, Colby, Ciara, Kisha/per1 McQuone

The sun helps to create the ozone layer by breaking apart oxygen molecules into single oxygen atoms. These single atoms can then recombine with other oxygen molecules to form ozone. Ordinary oxygen molecules have 2 atoms, ozone has 3. The ozone layer is vital to our survival as it absorbs most of the ultraviolet (UV) radiation from the sun. Too much UV causes cancer. There are many other processes that affect the ozone layer, like stirring up the Earth's atmosphere and injecting other chemicals. The worst chemicals are fluorocarbons contained in spray cans and air conditioners. If we produce enough of those chemicals, we could indeed wipe out the ozone layer.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

ROCKETS

QUESTION:
For how long can a sounding rocket collect data?

About 10 minutes. It will vary a bit with each payload. The SERTS payload has been reflown a number of times and between each flight modifications have been made. Usually these modifications make the payload a few pounds heavier. The highest point in the flight is now about 10 miles lower than the earliest flights and the observation time is about a little less as well.

SCIENTIST: Les Payne, NASA Goddard Space Flight Center

SATELLITES

QUESTION:
If the sun is so hot, how can they get a satellite close enough to tell anything about it? Can the sun's temperature change at different times of the year? from Cassie H./McQuone

All of the current satellites (ACE and SOHO for example) are a lot closer to the Earth than to the Sun and study the Sun from a long distance away (150 million kilometers or 92 million miles). There is a mission planned for the future called Solar Probe which will get within 3 million kilometers (2 million miles) of the Sun. It has an ablative shield (which vaporizes protecting the rest of the satellite). You can find out more about Solar Probe at http://umbra.nascom.nasa.gov/spd/solar_probe.html The Sun's temperature changes with time over it's 11 year cycle, but not by very much. Eric Christian For Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
What is the longest time a satellite can be used? What is the closest distance that a satellite can get to the sun? from Chris, Trinese, Carly, Julia/per 1 McQuone

Well, IMP-8 launched over 26 years ago and is still going strong! So some satellites last a very long time. About the closest distance that a satellite can get to the sun: Solar Probe, due to launch in 2003, is being designed to get within 4 solar radii.

SCIENTIST: Beth Jacob, NASA Goddard Space Flight Center

QUESTION:
How close could a person in a satellite get to the sun before they burn? from Rachel/per 5

t depends upon how good your cooling system is. There is an unmanned spacecraft (Solar Probe) which is being designed to get within 3 million kilometers (2 million miles) of the Sun, but it needs a special ablative shield which evaporates away, protecting the rest of the spacecraft. If you had a manned spacecraft, you probably couldn't get that close without a lot of work. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

SOLAR CYCLE

QUESTION:
How and when was the 11 year cycle of the sun discovered? What observations were made to determine that it was a cycle? from Rachel, Nicole, Brendan, Sam/per 4 McQuone

The 11-year sunspot cycle was discovered in 1843 by Schwabe. He simply counted the number of sunspots that were visible on the Sun every day and then noticed that the number went up and down with a period of around 11 years. Schwabe was an amateur astronomer, not a professional, and even today amateurs still make valuable contributions to astronomy.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
Does the Sun get larger as it goes through the years?

The Sun has some oscillation in its size, but it's quite small - people have done measurements by looking at the passage of other stars behind the Sun. However, the total amount of oscillation is small. The main change in the Sun's apparent size is due to Earth's orbit around the Sun - during the winter, we are closer to the Sun, and during the summer we are farther away. Therefore, the Sun looks 3% larger during the winter than it does in the summer. If you want to see a movie of how the Sun shrinks and grows in size, and to see how the tilt of the Sun varies throughout the year, take a look at: http://urania.nascom.nasa.gov/~zowie/coords/orbital-movie.html However, the Sun will expand a *lot* when it depletes its core of fuel, and begins the next stages of its life. Fortunately, that's not going to happen for billions of years, so we're all safe! thanks for the question! Dr. Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

QUESTION:
When the Sun dies will it explode or just disintegrate? Courtney

It will do neither. It will first expand into a red giant star, and all of the planets out to Mars will be inside the star. The Sun will then contract and eventually turn into a white dwarf star, which is very small but very heavy. In fact, all of the matter in the Sun will then be in a sphere the size of the Earth! A teaspoon of white dwarf matter weighs more than New York City. After it becomes a white dwarf, it will simply cool off until light no longer comes out of it.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

SOLAR MAXIMUM

QUESTION:
During Solar Maximum what will be the biggest effect we will notice on Earth? Maureen

Hello Maureen! Well, I'm not sure if you want to know whether you want to know what the biggest effect we'll personally notice is, or whether you want to know how they'll affect space systems and other things which we don't notice during the average day. I'll just assume you want to know how you'll personally experience it. Certainly the most interesting thing about solar maximum that we'll be able to see on the ground is aurora borealis activity - some people call them the "northern lights." They're spectacular! Huge colorful shining curtains of light in the sky caused by energetic particles hitting the atmosphere. During solar minimum you usually only seem them in the extreme northern parts of the United States, but during solar max they've been observed as far south as Puerto Rico! We hope you're interested in chasing coronal mass ejections with us, because if we see a big one, it might mean that if we go outside at night we can see an aurora. Other possible effects are not as pleasant. Some people have temporarily lost power, or television signals, or their cell phones have stopped working. Some of these sound like effects that normal weather storms cause - so "space storms" are also as exciting and important! Take care! Barbara Thompson

SCIENTIST: Barbara Thompson, NASA Goddard Space Flight Center

SOLAR OBSERVATORY

QUESTION:
Is there a particular reason that the observatories are domed shaped? from Colleen, Sara, Laura and Sally

Now that's an insightful question! The reason is that telescopes need to be able to look at any place in the sky, including low down. The best way to do this is have a slot in the roof, and to have the roof rotate. The best way to do all that is to have a dome for a roof. There are other shapes in use: Small telescopes frequently have a cube-shaped shed that just rolls away leaving the entire telescope out in the air. Also, there is now a trend towards 8-sided roofs with sides that completely open. This design allows air to flow across the telescope and makes everything the same temperature as the outside air. This reduces turbulence and improves the quality of the images.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

SOLAR PHYSICIST

QUESTION:
How did you know you wanted to be a solar scientist? Robert

Robert, my story is a bit unusual. I didn't really know until I got to graduate school. I have always been interested in physics and in mathematics, but could never make up my mind. When I went to college, I couldn't choose a major. I was having trouble deciding between journalism, art history, physics, math, and political science -- you can see that I was all over the board! By my third year, I noticed that I seemed to be taking a lot of physics courses, so I decided to be a physics major. When I applied to graduate school, I couldn't choose between high energy particle physics, solid state physics, or astrophysics. In the end, I found a research group full of people that I liked, and stuck with that. I think that, at some level, any field at all has enough interesting problems to keep a curious person going. So solar is definitely my field now, but I don't think it would have been the only one for me. The first time I remember being interested in the Sun was during the solar maximum in the late 1970s. I was a boy scout, and on a campout I remember getting up at dawn and watching the Sun come up. I saw some dark blemishes on the Sun and asked my dad about 'em. Fortunately he knew what they were (sunspots, caused by intense magnetic fields on the surface), and ever since I've been intrigued about our nearest star. I'll pass on some good advice I got from my father when I was younger. When charting your career, don't stress out over trying to pick a single field you'll follow for the rest of your life. Focus on what you'd like to do for the next few years. The long run will take care of itself, as long as you focus on the intermediate run. Cheers, Craig DeForest

SCIENTIST: Craig DeForest, NASA, Goddard Space Flight Center

STARS

QUESTION:
What causes the stars in constellations to sty together and never separate? Like the Big Dipper? Do others rotate or float freely? from Daniel/ Per 4 McQuone

Actually, all the stars in the sky are moving in different directions at very high speeds, typically 20 miles per second. However, since they are very far from us, it looks like the constellations have not changed since they were first recorded 10,000 years ago. If we could go backwards or forwards in time by several million years, then the constellations would look very different. There would be no Big Dipper.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

SUN

QUESTION:
What caused the density to increase at the core of the nebula cloud that formed the sun? from Chris/per 2 McQuone

Usually, it is the the gravitational attraction between the particles in the dust cloud that starts the whole process off. This attraction slowly contracts the cloud and increases the density in the core. It is also possible that a blast of radiation and matter from a nearby supernova could speed up the process.

SCIENTIST: Frank Hill, National Solar Observatory, Kitt Peak

QUESTION:
What causes the sun to rotate in that mysterious pattern? from Maggie/Per 2 McQuone

Sorry to be slow in getting back to you, I was tied up in a meeting.... ;-( That the Sun rotates is not a mystery; when you pull the plug in the bathtub and the water rushes out it almost never goes straight down the drain, but ends up swirling to the right or the left at a good clip. There's always a teeny tiny difference in the water going to one side or the other of the drain, and that "organizes" the water that follows. The same thing happens when a star is formed from a cloud of gas in "interstellar space". AND, as the cloud collapses to form the star [ in our case, the star we are living with - the Sun ] the rotation speeds up more and more as the star condenses. A good analogy is of a skater spinning around, who pulls in their hands and the rotation speeds up a lot. Try it on a stool that rotates BUT BE CAREFUL!! We thought that the Sun should be rotating much faster than we observe it to be doing, so there must have been a lot of rotating matter ejected as the Sun was forming, but even to how the rotation changes inside the gaseous Sun ***IS**** a mystery. BUT, it's a mystery we think we can solve. "We" means "you", and the next generations of scientists. Join the fun of the search!! g'luck John Leibacher

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

QUESTION:
How were people able to find out about the history of the sun, like how it formed? We were not there to see it. from Lee, Krissi, Lavondrick/ per 5 McQuone

Good question!!! Actually, and EXCELLENT question which goes to the heart of how science functions. We can observe the Sun today - it's mass, size, temperature, brightness, and that's about it until very recently - as well as other stars - once we figured out that the Sun was a star. Then the questions start to flow, like "why" and "how". For example, it wasn't until 50 or 60 years ago that people had an idea of where the Sun's energy came from. A hundred years ago people thought that the Sun was shining from gravitational energy from it's collapse from a gas cloud, and that seemed reasonable enough. One - very important - test of a scientific hypothesis is that it make testable predictions, and the idea [ "theory" ] that the Sun's energy came from the gravitational energy of its collapse predicted that the Sun should use up all of that energy in a few 100 thousand years [ and then die out ]. On a human time scale, there weren't any arguments against the prediction BUT geologists showed that there were rocks on the Earth that are MUCH older than this, so the theory was thrown out, and we now "know" that the Sun shines because helium fuses into hydrogen. I put "know" in quotation marks because we don't really "know" anything, we just have a pretty good description of the observations that explains the basic properties of the Sun and other stars, and is consistent with what we know about the Earth, long before human beings were around. BUT, one thing IS certain, what we "know" today isn't the whole story, and there are lots of mysteries still to be solved. That's ONE reason that science is so much fun!! best wishes, and thanks for the great question! John Leibacher

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

QUESTION:
Is it possible for anything to destroy the sun, like comets? from Kristy, Kelly, Jessica S., April

Compared to the sun, a comet is miniscule. In fact, if the sun were the size of a basketball, the earth would be about the size of a small pencil eraser. Comets are even smaller than that. So a comet crashing into the sun would not have much effect. (There are some cool pictures of sun-grazing comets out on the internet at http://umbra.nascom.nasa.gov/comets/SOHO_sungrazers.html). As for anything else? It's not likely that anything else could destroy the sun, other than its running out of fuel to burn.

SCIENTIST: Elizabeth Newton, NASA Marshall Space Flight Center

QUESTION:
Is it possible for their to be a life form that could exist on the sun? from Derrick, Katrina, John/per 7

I think it is very unlikely that any life form could live where the coolest temperature is 4000 degrees.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

QUESTION:
Is is possible that the sun is a bigger factor in the destruction of the atmosphere that air pollution? from Jessica H. per 7

I don't think so, Jessica. The Sun certainly sends out a lot of energy into space and is responsible for warming our planet and allowing life to flourish. But really things like volcanic gases and air pollution are much more immediate and direct agents that change the chemical composition of our atmosphere. Also, the Earth's magnetic field protects our Earth and its atmosphere from the Sun's most harmful particles that stream in the solar wind. So it's not very often that a solar event is going to be that destructive to our atmosphere.

SCIENTIST: Elizabeth Newton, NASA Marshall Space Flight Center

QUESTION:
Are there more neutrons than protons in the sun or are there an equal number? Blake George at Cranbrook M.S. Mr. Reynolds' class

There are more protons because there is much more hydrogen than anything else in the Sun, and hydrogen has a single proton and no neutrons.

SCIENTIST: John Leibacher, National Solar Observatory, Kitt Peak

TEMPERATURE OF THE SUN

QUESTION:
Will the Sun ever get too hot that it will effect animal and human life? Jodi

The Sun, in it's old age, will get larger and eventually become a red giant star, at which point the Earth will be to hot for us. But that is billions of years in the future. The Sun does get hotter and cooler with time, but the effects are relatively small. But ice ages and hot periods such as the Jurassic may be partially due to the Sun getting hotter and colder. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
How hot will the core be when it is burned out?

Probably warmer than the current 15 million degrees, but none of the half a dozen scientists here are experts in stellar modeling. Sorry. Eric Christian for Live from the Sun

SCIENTIST: Eric Christian, NASA Goddard Space Flight Center

QUESTION:
Is it possible to duplicate the temperature of the sun on earth? from Mack/per 4
The Sun is different temperatures at different places. Some places, like the photosphere are not that hot & we can replicate those temperatures in a laboratory. Other places are very hot & we can only replicate temperatures of millions of degrees in nuclear bombs. We can't do it at all in a controlled way.

SCIENTIST: Terry Kucera, NASA Goddard Space Flight Center

QUESTION:
Since the scientists have not probed inside the sun, how do they know the actual temperature of the inside of the sun? from Kate/ per 4 McQuone

We know what the energy source must be - nuclear fusion is the only thing that will give enough energy for long enough. From that we can estimate the temperatures. We can measure the details using helioseismology - measuring the vibrations of the Sun, see http://solar-center.stanford.edu/heliopage.html

SCIENTIST: Terry Kucera, NASA Goddard Space Flight Center

QUESTION:
Does the temperature inside the sun ever change?  from Christina/per 4 McQuone