BIG BANG THEORY BLACK HOLES CHANDRA GALAXIES QUASARS STARS SUPERNOVA
QUESTION:
Please explain some theories suggesting the origin of the universe besides the Big Bang Theory.
Thank you for your time in answering these questions.
Matthew Sung
ANSWER:
Right now the Big Bang does by far the best job of explaining the expansion of the Universe, the 3 degree or microwave background, and the mix of light elements still seen in stars and gas.
I don't believe there are credible competing theories - although some have tried to create a "steady-state" model for example, but these models don't fit the available data without more and more contrived assumptions.
SCIENTIST: Harvey Tananbaum QUESTION:
Please explain the theory that black hole winds allow some matter to escape from the black hole?
Thank you for your time in answering these questions.
Matthew Sung
ANSWER:
SCIENTIST: Harvey Tananbaum QUESTION:
Thank you for answering my question.
Sal ANSWER:
We don't for sure the distance to the closest black hole. It is possible that very small, low-mass black holes exist that we are simply unable to detect with our telescopes, and these could be anywhere - even flying through our solar system.
What we do know is that there are black holes which weigh 5 or 10 times as much as our Sun (actually they have a mass 5-10 times that of the Sun), and that these black holes are part of double star systems called binary stars. Some of these binary stars with a black hole are a few thousand light years away from the Earth - in our Galaxy and really not that far away by astronomical standards.
SCIENTIST: Harvey Tananbaum QUESTION:
Anthony
ANSWER:
We usually talk about a blck hole's mass when we consider how big a black hole might be. We usually give the mass relative to the mass of our Sun. We know about black holes in our Galaxy which are members of double star (binary) systems, where the black hole mass is 5 or 10 times greater than the mass of our Sun. In the centers of some distant galaxies (also called active galaxies and quasars), the black hole mass can be 100 million or even 100 billion times that of our Sun. Imagine that - cramming 100 billion suns into a small region of space - no bigger than our solar system - that's why the force of gravity around a black hole can be so strong!!
SCIENTIST: Harvey Tananbaum QUESTION:
Why do black holes shoot streams of matter in opposite directions?
Thank you for your time in answering these questions.
Matthew Sung
ANSWER:
There are two possibilities -
First, when matter falls onto a black hole it does not come directly down, but swirls around and forms a disk of matter like a frisbee. The spinning matter sometimes throws off material that forms the jets. Complex processes like twisted magentic fields help to stablize the jets.
The second cause is that black holes themselves have sin (in fact there are just three qualities that characterize a black hole - mas, spin and charge). The spinning black hole requires matter falling in to also spin and just as with the previous process, the spinning matter then can produce jets streaming out fromt he spin axis
SCIENTIST: Steve Murray QUESTION:
If black holes are ever-expanding, is it accurate to say that everything will eventually be enveloped in a black hole?
Thanks, ANSWER:
A good question. The answer is not so simple. The rate at which black holes can collect matter depends on the density of material around them. As the universe expands, isolated black holes (if there are any) will simply not be able to gobble up matter faster than then matter is spreading out inthe Universe. For black holes inside galaxies, the matter near them will eventually fall in but matter far away can remain stable in orbit around the black hole for a very long time, longer then the curernt lifetime of the universe. Depending on the ultimate fate of the unoverse, there may not be enough time before a big crunch for black holes to engulf everything. If there is no big crunch and the unoverse expands forever, then it is likely that the black holes will still not be able to have strong enough gravity to overcome that expansion and again not everything will wind up inside blackholes.
SCIENTIST: Steve Murray QUESTION:
Thank you for answering my question.
Ryan ANSWER:
SCIENTIST: Steve Murray QUESTION:
William T.
ANSWER:
The time for a star to evolve into a black hole depends on the initial size (mass) of the star. The very massive stars age quickly and could become black holes in 10's to 100's of millions of years. Less massive stars take longer, and when the star mass is low enough then it will not become a black hole at all, but a neutron star or white dwarf might result. These stars ca nlass for billions of year before they collapse.
SCIENTIST: Steve Murray QUESTION:
Matt Sung
ANSWER:
The majority of black holes may not be at the centers of galaxies. Lighter black holes which are the result of stellar evolution (a few solar masses) are spread thoughout a galaxy just as the stars are. As the masses of black holes increase (coming from more massive stars) there is a tendancy for the stars to slowly sink towards the galaxy center, just as heavy rocks settle to the bottom of a mixture and lighter sand remains on the top. The more massive the black hole the faster it can sink and the more likely to get to the galaxy center.
Supermassive black holes are at the center of a galaxy, because they formed there initially or because they have had the time to sink into the center and collect there.
SCIENTIST: Steve Murray QUESTION:
Crystal Vannatter ANSWER:
Our Sun is not sufficiently massive to become a black hole. As it evolves over the next several billion years, it will eventually run out of "fuel" - the nuclear material which provides the Sun's power through the fusion process. When the core of the Sun is mostly iron and it can't fuse the iron into still heavier elements, the outer envelope of the Sun will expand (as a red giant - unfortunately even enveloping and incinerating our Earth). The core of the Sun will shrink to a size comparable to the Earth and will become a white dwarf star, capable of supporting its own weight and radiating a lot less light and heat than the Sun currently produces - but no Black Hole.
SCIENTIST: Harvey Tananbaum QUESTION:
How will the X-ray images from the CHANDRA telescope help further the advancement of our knowledge about space?
Thank you for your time in answering these questions.
Matthew Sung
ANSWER:
SCIENTIST: Dr. Martin Weisskopf QUESTION:
Where, exactly, is the Chandra orbiting? What type of objects can X-ray telescopes, such as Chandra, pick up?
Thanks, ANSWER:
Amazingly enough, Chandra has seen x-rays from every type of astronomical object - including comets, planets (Jupiter), normal stars, galaxies, clusters of galaxies. You name it and it (or a subset thereof) emits x-rays.
SCIENTIST: Dr. Martin Weisskopf QUESTION:
Approximately how much money is, and has been, invested in the Chandra telescope?
Thanks, ANSWER:
SCIENTIST: Dr. Martin Weisskopf QUESTION:
How can we take pictures of our galaxy, I thought the only way was to send out a probe and take pictures from the outside. I can see how we take pictures of other galaxies, I always hear my mom saying stuff like we are right here on the Sagittarius arm, but how can she show me our entire solar system in a picture unless it was taken from outside?
Thank you for your patience in answering my lengthy questions
Karmen Snoeberger
ANSWER:
SCIENTIST: Dr. Martin Weisskopf QUESTION:
Could there be other Earth's forming in other sectors of our own galaxy that just haven't reached our state of evolutionary refinement?
Thank you for your patience in answering my lengthy questions
Karmen Snoeberger
ANSWER:
-martin elvis
SCIENTIST: Martin Elvis QUESTION:
Michelle L.
ANSWER:
SCIENTIST: Dr. Ron Elsner QUESTION:
Thank you for answering my question.
Andrew B. ANSWER:
SCIENTIST: Pat Slane QUESTION:
Alyssa ANSWER:
The reason stars appear to be shaped "like a star" is really an effect caused by the telescopes that we use to observe them (or even our eyes). To see this, look at a small light bulb across the room. Now squint your eyes. Do you see all the rays of light that seem to come out to the sides now? That's the result of using a small slit (your eyelids) to look at the light. When we look at stars, we use telescopes that have a certain width, and if these aren't wider than about 10 inches, we get the same sort of effect that makes the points of like look like "stars." Another effect is the jumbling around of pockets of air in our atmosphere. Did you ever look at something across the hot hood of a car, or over a hot road in the summer, and notice that it looks "wavey?" That's because air pockets of different temperature bend the light coming to you a little differently than the pockets nearby. The same thing happens when you look up at the stars, even with a telescope. This "turbulent atmosphere" makes the stars "twinkle." One way to get around this is to put the telescope in space, and that's why Hubble can get such great, crisp pictures.
SCIENTIST: Pat Slane QUESTION:
ANSWER:
SCIENTIST: Pat Slane QUESTION:
Thank you,
Matt
ANSWER:
This is a bit of a tricky question. The brightest one that I know of was probably SN 1054, which produced the Crab Nebula and pulsar. This one was apparently as bright as the full moon and visible in the daytime for several weeks. But that's because it was somewhat close. If, instead of observed brightness, you want to know which was most energetic, that's a hard question because it is difficult to account for all the energy of the explosions when we see them. Some current theories suggest that Gamma-Ray Bursts may be supernova-like events. In this case, these would be the winners, with energies greater than 10^52 ergs (that's 10 raised to the 52 power!).
SCIENTIST: Pat Slane QUESTION:
Elizabeth
ANSWER:
Supernovas occur when the core of a very massive star runs out of fuel. The normal process is to have nuclear fusion at the center of the star produce pressure that supports the outer layers (which are trying to fall inward because of gravity). When the fuel runs out, the core collapses and the outer layers fall in, collapsing the core. If the star is massive enough, this infall can cause a supernova explosion.
We know that only stars that are at least about 5 times as massive as the sun can undergo such an explosion. So we can certainly identify candidate stars. But even the very massive stars (which have the shortest lifetimes) live for tens to hundreds of millions of years, so it's impossible to pinpoint the actual time when this will happen. There are signatures of when the star has begun to evolve to this point, but even though the collapse itself is very rapid, the star can linger in the final stages for quite a long time.
SCIENTIST: Pat Slane
Hi! My name is Matthew Sung, and I am a senior at Muncie Southside High School in Muncie, Indiana
Hi Matthew,
Director, Chandra X-ray Observatory
Hi! My name is Matthew Sung, and I am a senior at Muncie Southside High School in Muncie, Indiana
We think that some black holes (maybe all black holes) are spinning. Now imagine a merry-go-round - if you try to climb on-board by running directly at it, you may simply bounce off it. If instead, you run along side the merry-go-round and match its spin, then it is much easier to jump on-board. We think something similar is happening as matter falls towards a spinning black hole. If the material falls directly towards the black hole and does not much its spin rate, then the matter can get bounced or flung away from the black hole. In this case the matter never quite got to the black hole before being ejected.
There are other processes - called Penrose radiation I think - where particles can be created within the black hole (or near its surface) and can in some cases be ejected carrying energy out from the black hole (and causing it to gradually evaporate). These "winds" are still theoretical - we don't yet know how to observe them to see if they really exist.
Director, Chandra X-ray Observatory
How close is the closest black hole to Earth?
Beers Street Middle School
Hi Sal,
Director, Chandra X-ray Observatory
About how big is the biggest black hole found and how long do they last?
Hi Anthony,
Director, Chandra X-ray Observatory
Hi! My name is Matthew Sung, and I am a senior at Muncie Southside High School in Muncie, Indiana
Dear Matthew:
Instrument Builder and Chandra X-ray astronomer, Chandra X-ray Observatory
My name is Jacob Clark and I am a junior at Muncie Southside High School in Muncie, Indiana.
Jacob Clark
Dear Jacob:
Instrument Builder and Chandra X-ray astronomer, Chandra X-ray Observatory
Does a black hole have a temperature?
Beers Street Middle School
This is a question that has not actually been answered to everyone's satisfaction. According to Hawking, black holes can evaporate (especially very small ones), and therefore they can be characterized by a very low temperature. But more recent theoretical work suggests that the evaporation (by production of what are called virtual particles) is not quite so random as is needed to use the concept of a temperature to describe the process. Put more simply - we aren't really sure, but if black holes do have a temperature we are sure it is very very low.
Instrument Builder and Chandra X-ray astronomer, Chandra X-ray Observatory
About how does it take for a star to begin until it becomes a black hole?
Dear William:
Instrument Builder and Chandra X-ray astronomer, Chandra X-ray Observatory
Why are majority of black holes in the centers of galaxies?
Dear Matt:
Instrument Builder and Chandra X-ray astronomer, Chandra X-ray Observatory
Will the Sun ever become a black hole?
Muncie South Side High School, Muncie, IN
Hi Crystal,
Director, Chandra X-ray Observatory
Hi! My name is Matthew Sung, and I am a senior at Muncie Southside High School in Muncie, Indiana
Hi Matthew - there is a short answer and a very long one. Here is the short one: By studying the x-ray emission from pbjects -- everything from normal stars to quasars we get a better understanding of what makes these objects tick (how they work - produce energy, come into existance, evolve and die). Understanding these processes satisfies not only our curiosity but improves our understanding of basis physics.
Project scientist for NASA's Chandra X-ray Observatory, NASA's Marshall Space Flight Center, Huntsville, Ala.
My name is Jacob Clark and I am a junior at Muncie Southside High School in Muncie, Indiana.
Jacob Clark
The Chandra Observatory orbits around the earth - going about 1/3 of the way to the moon at the peak of the (elliptical) orbit.
Project scientist for NASA's Chandra X-ray Observatory, NASA's Marshall Space Flight Center, Huntsville, Ala.
My name is Jacob Clark and I am a junior at Muncie Southside High School in Muncie, Indiana.
Jacob Clark
This project started in 1976 more than 24 years ago. The total cost to get it built and up there (including about 500 $M for the shuttle launch was about 2 $B. Sounds like a lot but remember to compare to say even one aircraft carrier. Cost to operate is about $60M per year.
Project scientist for NASA's Chandra X-ray Observatory, NASA's Marshall Space Flight Center, Huntsville, Ala.
Hello, my name is Karmen Snoeberger and I am a Junior at Muncie Southside Highschool in Muncie Indiana.
Hi Karmen,
You are right, of course, we cannot get a real picture of our own galaxy because we are in it. On the other hand by looking out and tracing the structure, by comparing with other galaxies that we can see completely, we can infer what our galaxy does look like if viewed 'from the outside".
Project scientist for NASA's Chandra X-ray Observatory, NASA's Marshall Space Flight Center, Huntsville, Ala.
Hello, my name is Karmen Snoeberger and I am a Junior at Muncie Southside Highschool in Muncie Indiana.
Hi Karmen:
There are lots of planets forming around new stars - the Orion nebula is pretty nearby (a few hundred light-years) and has hundreds of new stars. We can't yet see Earth size planets anywhere outside of our Solar system, but it looks more and more likely that they are pretty common. Are any at our evolutionary level? hard to say - we would be dificult to find from another star. NASA plans to build telescopes to find Other Earths, but it is some way from being launched.
Senior Astrophysicist, Harvard-Smithsonian Center for Astrophysics
How do quasars affect the Earth and all other planets?
Quasars are so very far away that they have no effect on our solar system. Except that they intrigue some humans on Earth and cause them to point telescopes at them.
Astrophysicist, NASA's Marshall Space Flight Center, Huntsville, Ala.
Is it possible for a star to be hotter than a white dwarf? If so, what is the highest temperature that we have seen emitted from a star?
Beers Street Middle School
Yes, the surface temperature of a young neutron star is hotter than a white dwarf. We've observed temperatures of over a million degrees (Kelvin) from several of these stars. They are so hot that they radiate most of their energy in x-rays.
Chandra Science Mission Planning group, Harvard-Smithsonian Center for Astrophysics
Why do stars appear to be shaped like a star but in reality they are balls of gas?
Beers Street Middle School
Hi Alyssa:
Chandra Science Mission Planning group, Harvard-Smithsonian Center for Astrophysics
Could you explain why Type Ia Supernovae, if they always have the same absolute luminosity should appear more or less bright for reasons OTHER than their relative distance?
Was the distance to the supernova in Tuesday's press release found using ANOTHER method that conflicts with the standard results of Type Ia luminosity results?
Is that the reason that the results show a "brighter" older universe due to gravity dominance versus a "younger" dimmer universe due to the current acceleration (Vacuum energy, Dark Energy, etc.)?
There are a number of reasons that Type Ia SNe could appear fainter for reasons other than distance. For example, absorption or scattering can remove light from the line of sight. These effects are taken into account in modeling the emission for a particular SN though. For the supernova discussed in the press release mentioned, however, it actually *is* distance that is the important issue. Recent work has shown that Type Ia SNe appear dimmer at large distances that one would expect from a uniformly expanding universe. The prevailing theory is that this is because the "cosmological constant" representing the vacuum energy causes an expansion that is more rapid than that from a simple matter-dominated universe. The new result is for a supernova at a larger redshift (thus distance) than has been measured before. By assuming a cosmological constant, based on the other Type Ia work, one can predict how bright this one should appear. It appears brighter. A proposed explanation is that at a much earlier time, when the Universe was dominated by matter, the cosmological constant did not have as strong of an affect on the expansion; things were expanding more slowly than they are now. The new observation appears to show the effects of this epoch of matter-dominated expansion. I haven't read the technical paper on this result yet, so I can't provide a more authoritative reply on the results than this.
Chandra Science Mission Planning group, Harvard-Smithsonian Center for Astrophysics
What is the largest supernova you know of?
Hi Matt:
Chandra Science Mission Planning group, Harvard-Smithsonian Center for Astrophysics
How do supernovas occur and is there any way to tell when a supernova might occur?
Hi Elizabeth:
Chandra Science Mission Planning group, Harvard-Smithsonian Center for Astrophysics