Astronomy/Questions Answered by Expert James Gort

SubjectDate Asked
cosmology1/21/2017
  Q: ..I have just read the latest answer you gave to a question and would like to ask, further to that. ...
  A: I'll try and answer your fairly long question as simply and succinctly as I can. And it will be to ...
Cosmology1/10/2017
  Q: I'd like to know why scientists say that the universe is expanding, based on the findings of Mr. ...
  A: You are correct. Observations "seem" to support that galaxies are receding - from us as well as from ...
Stars5/24/2016
  Q: How do stars stay together so well?
  A: The answer is gravity. The same thing that keeps the earth together also keeps the stars together. ...
universe expansion5/19/2016
  Q: ...has anyone considerred that dark matter may degrade in some way? An increase in acceleration of ...
  A: I'm not sure if that's actually been proposed in any peer-reviewed publication, but I don't see why ...
Follow Up Question5/14/2016
  Q: So do we know any of these new constellations? Has the human race in the past seen these ...
  A: Humans have imagined all sorts of constellations before, but all were made up of the same stars we ...
Black Holes5/11/2016
  Q: How do stars and planets orbit a black hole without being destroyed by it
  A: This is a common misconception about black holes. Black holes do not have any more gravity than any ...
Stars5/11/2016
  Q: Are we ever going to see new constellations, or are the ones we see now always be there?
  A: When you say "we", I assume you mean in your lifetime. In that case, the constellations you see will ...
the Sun4/3/2015
  Q: I have been learning about the Earth's orbit at school, and would like to know why the Sun never ...
  A: When you're learning about the earth's orbit, I hope you're also learning about the earth's rotation ...
star formation3/10/2015
  Q: A third grade student of mine is working on a personal learning project and she is wondering: 1. ...
  A: I'd be happy to help. About the third grade is when I became interested in the stars - and the ...
solar ignition1/6/2015
  Q: I have read several books on solar evolution but I'm interested in one particular event. When the ...
  A: I think your question can be answered by a Hayashi Track diagram - see ...
Scope1/1/2015
  Q: As far as what we know about distances of all stars and planets in our galaxy outside of our own ...
  A: We know the distances of nearby stars quite accurately, and the distances of more distant stars in ...
Astronomy12/22/2014
  Q: Are there any galaxies with planes of rotation almost perpendicular to the line of sight with large ...
  A: Interesting question. The short answer is - none that I can find! The pre-print "The Asymmetry of ...
quantum physics11/26/2014
  Q: simple questions...sort of! Can quantum theory make any prediction on a SINGLE event? The 2 slit ...
  A: First, I apologize for the late answer, but I was out of town. To answer your question, it seems ...
Four black hole time dilation question for you.6/25/2014
  Q: Can you please help with these questions, cannot find the answers to these questions Online, or on ...
  A: Forgive me if I thought these were "homework" questions. Not many people ask as detailed questions ...
Counting stars within given time & volume6/13/2014
  Q: Gort, I would like to make two separate estimates of the total number of stars that have ever ...
  A: First of all, I like your two estimates. They're very well thought out. And they identify some of ...
orientation6/8/2014
  Q: I have had something on my mind recently, on a grand scale. The direction or orientation of ...
  A: I don't know whether this answer will help you much or not. But for orientation purposes, I wouldn't ...
Space Junk?5/14/2014
  Q: I'm doing a project for school, and I was wondering how long you think it will be before we can go ...
  A: Since it's a school project, I won't give you the answers. Actually, there aren't any "definitive" ...
Astronomy5/13/2014
  Q: What exactly is a super nova, and could they be harmful?"
  A: A supernova is, literally, a "brilliant new star", or, more precisely, an exploding star. And, yes, ...
Astronomy5/9/2014
  Q: How could you find out what is farther than beyond what we? Like we know we are in this huge ...
  A: We may never know! But probably the best source to get more details (since it's too lengthy to ...
Pleiades star cluster5/9/2014
  Q: The Pleiades star cluster when you look at them the stars seem close together, what's the actual ...
  A: The Pleiades cluster contains about a thousand stars in a radius of about 8 light years. If you ...
Distance to stars5/6/2014
  Q: I read this in a discussion group, is there any truth to this? some astronomers feel that it is ...
  A: No, there's no truth to that. At least among the main stream astronomers. There might be a few ...
Venus and Mars if they switched orbits4/23/2014
  Q: Venus has held a special interest for me for awhile, so I am curious to know what happen if Venus ...
  A: This simple question is quite complex to answer. There are sophisticated computer programs which ...
Black Holes & Big Bang3/8/2014
  Q: Presumably Black Holes / Singularities give birth to new universes. Our universe is expected to ...
  A: I sure wish I could answer your question definitively. But I'm in good company. Because no one can. ...
Speed of Light and Black Holes2/8/2014
  Q: Gort, I am Sam and I am studying the universe in Enrichment class and I am wondering if you can ...
  A: First of all, it's a little confusing when you say that "eyesight bends around you". Your eyesight ...
Accelerating Universe2/5/2014
  Q: Can't the puzzle of the accelerating universe be answered by multiple/infinite universes and their ...
  A: Yes, it can. And probably the best source to get more details (since it's too lengthy to describe ...
Black hole and space1/31/2014
  Q: Sorry for my English but it is not my natural language. I am a computer engineer sorry for maybe ...
  A: Buongiorno, Thomas! Il tuo inglese molto buono! But I think I'll stick with English - my Italian ...
Can you orbit a neutron star to time travel into the future, and keep the people in the space shuttle safe1/30/2014
  Q: Can you please help with these neutron star questions. they are not homework, or term paper ...
  A: You ask some very interesting questions! I'll try and answer the best I can, and I'll explain the ...
Space Junk5/9/2013
  Q: What is the main reason that there is so much trash in orbit today?
  A: The simple answer is because we put it there. Nearly every rocket launched for over 50 years has ...
Mars and Jupiter10/24/2012
  Q: Could a human being with perfect eyesight see Jupiter in the Martian night-sky, without using a ...
  A: I've used the closest approach of Venus to Earth (37.8 million km), and the closest Mars gets to ...
Orbital ferrofluid telescope10/12/2012
  Q: One of the main logistic problems with telescopes are the large refractors/reflectors, especially if ...
  A: Yes, I think it's very viable, but like most things, subject to some practical engineering ...
Double suns10/9/2012
  Q: In a binary solar system populated by 2 suns close together, would it be theoretically possible ...
  A: This is a very interesting question! The short answer is "yes and no"! But let me explain. In ...
Inaccuracies of Astronomy website etc.9/30/2012
  Q: A long while back, I found a fascinating website ...
  A: Regarding the average temperature of the earth-like planet at 1 A.U., one of the problems with a ...
Approaching asteroid9/24/2012
  Q: Professor- In a story I'm working up, an asteroid is launched(long story made short) from the ...
  A: Interesting question. I'm sure you know that LINEAR has a 90% probability of discovery of even slow ...
Resistance to planet surface9/18/2012
  Q: > sorry but I don't answer homework questions. James I appreciate your concern however I'm 52 years ...
  A: It certainly sounded like a homework question - not the sort of question one normally wonders about! ...
GRBs9/15/2012
  Q: James, I have another question. What percent of gamma ray bursts (presumably from hypernovae)are ...
  A: According to recent research, the beam width of GRBs is between 2 and 20 degrees. See ...
Type 1A supernova9/15/2012
  Q: James, Does a type 1A supernova leave a remnant? Thanks, Paul
  A: It depends on what you mean by a remnant. All supernovae (of all types) produce remnants, but only ...
higgs2!8/6/2012
  Q: it was very helpful. I realise il never get my head around quantum theorys but that fact doesnt seem ...
  A: Believe me, you're not the only one who finds quantum theory hard to understand. No one really does, ...
star formation8/4/2012
  Q: What are the actual indicators that astronomers use when they see a bright spot in space, for ...
  A: The main two indicators which astronomers use to determine that a star is forming (or very young) as ...
higgs7/11/2012
  Q: I have a few questions stimulated from the possible discovery of the Higgs particle. I realise the ...
  A: This is not an easy question to answer. Many times, one can relate the theory (what physicists think ...
the largest known star7/9/2012
  Q: James. Hope all is well. According to Wikipedia, the largest known star is VY Canis Majoris. The ...
  A: Yes, I believe VY Canis Majoris is the largest known star, but I don't think the information is ...
characteristic time7/6/2012
  Q: Ive been wondering since i read about black hole's characteristic time which mentions: all charged ...
  A: I couldn't find any source to verify your quoted rapid discharge rate. Please give me a source, and ...
Rogue Star7/4/2012
  Q: I was checking a game on the astronomy workshop website which was about calculating the orbit of a ...
  A: Celestial mechanics are notoriously difficult to estimate without a solid mathematical model. I ...
rotating object near black hole6/12/2012
  Q: Gort I've been wondering since your answer by Paul in ...
  A: That's exactly right. The object's angular momentum will cause the black hole's angular momentum to ...
viewing the sun5/25/2012
  Q: I was just wondering if one can use some x-ray film to safely view the sun with the naked eye. If ...
  A: Although I am not familiar with the optical properties of developed or undeveloped x-ray film, I ...
Astronomy and Science5/19/2012
  Q: How many galaxies have scientists found in space?
  A: The answer is - they haven't all been counted! There's just too many of them. Every photograph of ...
300,000 kilometer rod extending from sun5/8/2012
  Q: Professor Gort, I enjoy looking at the SOHO observatory pics of the sun, and I noticed in ...
  A: Interesting observation. Although I don't have an immediate answer for you, I will find out the ...
entanglement12/14/2011
  Q: I have just read the following 2 books: 'Imagining the Tenth Dimension' by Rob Bryanton, 2006 and ...
  A: Let me preface my remarks with the comment that my research has not included the "early universe" ...
Things to do on a budget.....11/12/2011
  Q: Several of my friends and I have a lot of interest in astronomy and wish to get into backyard ...
  A: Yes, indeed there is! But let me first say that one of the most important things you can do (IMHO) ...
What would happen to the earth if an asteriod hit the moon?10/16/2011
  Q: What would happen to the earth if an asteroid hit the moon? Would we as people be affected. Would ...
  A: A lot depends on the size of the asteroid. If it had enough mass to eject material beyond the ...
Supernova10/15/2011
  Q: Gort, I recently saw an astronomy documentary about supernovas, and they said that Betelgeuse--one ...
  A: You've asked a very interesting question, and one in which there has been some research, but no ...
light10/2/2011
  Q: I Have some questions related to light. They are stimulated from the recent 'alleged' speed of ...
  A: I'll do my best to answer the question. But the "why" question you ask - why neutrinos have the ...
Star formation9/27/2011
  Q: I have a hypothetical question. Ok lets start with a large 1st generation star. Now lets say that ...
  A: Interesting hypothetical situation. Although your assumption that a second generation star needs a ...
Science Fair Project dealing with Yarkovsky Effect9/20/2011
  Q: My name is Matt. I'm in the 8th grade and I'm working on a science fair project this year that ...
  A: Just a suggestion. I think this is still a good idea, but keep in mind that results will be ...
Why I doubt vising aliens exist8/24/2011
  Q: There are a lot of articles at the moment regarding whether aliens have, or do, visit planet Earth. ...
  A: I certainly understand your reasoning, and others (including many scientists) have made similar ...
BIG BANG8/20/2011
  Q: i was watching this documentary on BIG BANG on discovery channel and there i heard a couple of ...
  A: You've asked a lot a important questions. And no matter what you've heard, astrophysicists don't ...
Satellites8/7/2011
  Q: If you can not answer this question maybe you know someone who can. I used to frequent J Track at ...
  A: Apparently, NASA, specifically Marshall Space Flight Center, has restricted access to J-Track and ...
The creation of the Universe7/31/2011
  Q: During hundreds of years scientists have been concerned about how the Universe was created. ...
  A: First, although I'm an astronomer (actually, an astrophysicist), I am not so arrogant as to think I ...
Can Pulsars be seen from Earth without Telescopes?7/29/2011
  Q: I'm a bit confused whther pulsars can be seen with the naked eye or not. This site says no ...
  A: M., No known pulsars can be seen with the naked eye. But, of course, they can be "seen" from earth ...
Elliptical Orbits7/21/2011
  Q: Why all the planets and stars revolve around everything in an elliptical orbit rather circular? If ...
  A: First of all, I want to remind you that the origin of the universe by a "Big Bang" is very much ...
How far can we see7/20/2011
  Q: An article in the current Scientific American says that we can see out to 42 billion light years. ...
  A: A "good" explanation can be found at http://en.wikipedia.org/wiki/Observable_universe. That wiki ...
Habitable planets7/15/2011
  Q: I have been using the build your own solar system gimmick on this website:- ...
  A: I agree with you. A few things don't seem right. If you put Earth's characteristics in the model, ...
evolving stars?1/11/2011
  Q: just for the record I am an sixth day creationist I humbly do not believe the macro-evolution or big ...
  A: First, let me be on record that I have an open mind about the big bang. My personal view is that ...
Hubble equation1/9/2011
  Q: I am reading an astronomy text and have come across what appears to be a contradiction, and I ...
  A: Interesting question. First of all, I want to remind you that the origin of the universe by a "Big ...
Quantized Red Shift1/2/2011
  Q: I have been reading on the quantized red shift discovered by William Tifft in the 70s. From what ...
  A: First, I don't think that the Tifft quantization of redshift is widely accepted. I believe that ...
career guidance4/30/2010
  Q: Sir,I'm Genny from India.I'm in 10th standard now.I have a great passion towards astronomy and would ...
  A: I am glad to hear of your interest and passion for astronomy. To me, that is the main ingredient ...
universe etc!4/29/2010
  Q: i thought you answered my last question informatively without being belittling so i wondered if you ...
  A: That's actually an interesting idea, but maybe I can suggest a few things to help it along. First, ...
rotation4/27/2010
  Q: i am not sure if this has any significance or not but i imagine it might. as we look in on the sun ...
  A: This is definitely not a simplistic question. In fact, it's probably one of the most ...
Seeing the milky way.4/25/2010
  Q: How do we know what the milky way galaxy actually looks like? Are the images we have of it only ...
  A: Since we're inside the Milky Way, the only way we "know" what it looks like is by mapping the stars ...
A Problem/Observation About the Big Bang4/24/2010
  Q: Mr. James Gort, First, I would like to say that I lack any college level education in on the subject ...
  A: First of all, I want to remind you that the origin of the universe by a "Big Bang" is very much ...
about Moon4/23/2010
  Q: ####What's the true shape of Moon's path traveled FOR ONE SYNODIC MONTH around the Earth (according ...
  A: Merci Beaucoup, Edd, Just compute the velocity of the moon due to its motion around the earth and ...
anti matter4/19/2010
  Q: it was very helpful. Just one more question please that arose on reading your answer. Can any of the ...
  A: Just a follow-up and a suggestion. Get the book "Antimatter" by Frank Close. It's a small ...
anti-matter4/15/2010
  Q: Sir, i would like to know a bit about anti-matter. Is it speculated that other areas of the ...
  A: Yes, there may be entire anti-matter galaxies, and the physics of star formation, black hole ...
The Early Universe4/11/2010
  Q: If the images we are able to take now of the early universe are how it looked billions of years ago, ...
  A: The early universe looks very much like the present universe. To a very large degree, the universe ...
space4/10/2010
  Q: optimistic values for the terms in the Drake Equation particularly for L, will give a large N, ...
  A: This sounds like a homework question. Hope it isn't, because I'll answer it. Here are three ...
entropy4/3/2010
  Q: James, Thank you VERY much for your answer, it was VERY helpful, and I have just order the Kip ...
  A: I just want to understand your question properly. If the cold object enters the hot universe, and ...
Planetary Alignment 20121/7/2010
  Q: How many planets are expected to line up in 2012?
  A: There is no unusual planetary alignment in 2012. The most "interesting" alignment will be a transit ...
Supernova effect1/6/2010
  Q: There was some mention in the media about a supernova, T Pyxidis, being about to blow up any time ...
  A: That's a really interesting question! I'm going to go through a "back of the envelope" calculation, ...
Effect of a GRB On The Sun at The Peak of Its 'Sun-Spot' Cycle1/2/2010
  Q: What would be the effect on the sun (if any) if a powerful gamma-ray burst were to hit it directly, ...
  A: Interesting question! And this is one that we don't have a lot of observational evidence to ...
Black holes, electric charge6/11/2009
  Q: Since not even light can escape the event horizon of a black hole, if a black hole managed to ...
  A: I'm not quite sure I understand your question. I'll assume "beyond" the event horizon means ...
Sun and 7.25 degrees.....1/21/2009
  Q: I have been reading through the questions and this seems to pop up quiet a bit. The question I have ...
  A: You are correct that there's no absolute frame of reference. However, in our solar system, the ...
solar system1/20/2009
  Q: I am an young earth creationist so you know I think the big bang is a fairytale.My two questions are ...
  A: First, you may be surprised when I tell you that I'm a creationist also. I don't know of too many ...
stars1/18/2009
  Q: why do all stars seem like there the same distance from earth. And does this have anything to do ...
  A: All the stars seem like they're at the same distance from earth because they're all so far away. ...
Bright Star?1/13/2009
  Q: Hey James, Every clear night for the last week or so (could be longer can't say I've purposely ...
  A: The object that's caught your eye is actually not a star at all, but the brightest planet there is - ...
black holes1/9/2009
  Q: i am 17 years old and i was wondering is it possible that when a star dies and produces a black ...
  A: We have a pretty good idea of how elements burn in a star's interior, starting mainly with a sphere ...
partical collisions?1/8/2009
  Q: Professor Gort, in your reply to my last question (small cold sun) you said: charged particles from ...
  A: Yes, we have a pretty good idea of how fast these particles are travelling. In some types of stars, ...
Small cold sun?1/7/2009
  Q: Professor Gort i'm not going to be very popular i think. I want to question the present sun theory. ...
  A: Believe me - there are no silly questions - only silly answers! And I hope this answer isn't one of ...
expansion of the universe1/7/2009
  Q: I am wondering, since the expansion of the universe is accelerating, has there been any detailed ...
  A: You ask some very thoughtful questions! I hope to give you a little more "food for thought". First ...
Supernova1/2/2009
  Q: How the mass and distance of a supernova affects objects in the universe? How forces influence the ...
  A: To answer your second question first, a supernova is just an "exploding star", so the forces that ...
telescopes5/6/2008
  Q: why do telescopes in space get a more complete picture of space objects?
  A: Telescopes in space are outside of earth's atmosphere. Telescopes on earth must see through a very ...
earths orbit5/5/2008
  Q: how does the earths rotation stay relatively predictable/constant???
  A: Isaac Newton discovered the law of inertia - that an object at rest stays at rest, and an object in ...
SIZE OF OBSERVABLE UNIVERSE4/26/2008
  Q: Gort, One of my biggest question is about the size of the observable universe. In one of your ...
  A: As the red-shift gets greater, it appears that Hubble's velocity / distance "law" is not linear. ...
lightyear9/4/2007
  Q: How long does it take for the images of the stars in the sky to get here?
  A: The time it takes for light from stars to reach us depends on how far they are away. The nearest ...
Black Hole Collapse Velocity9/2/2007
  Q: When a large star collapses to a black hole why doesn't the collapse velocity approach the speed of ...
  A: I forgot to mention on the "rotation" question, all angular momentum is measured at the event ...
Black Hole Angular Velocity9/2/2007
  Q: When a massive rotating star collapses to a black hole why isn't the rotational angular velocity of ...
  A: When a rotating star collapses, you are correct that conservation of angular momentum (which is ...
How did the observable universe get so big in so "short" a timem5/28/2007
  Q: In a recent lecture it was stated that the observable universe is fourteen billion years old, but ...
  A: I wish I had attended that lecture! First, let me say that this is a highly speculative area, and ...
string theory5/26/2007
  Q: I want to ask that according to string theory there was not any singularity at beginning of ...
  A: I'm not sure I can help much in this speculative area, but I'll try. First, I hope you've had a ...
moon color5/20/2007
  Q: What color is the moon? Do you know of a book or website to support your answer?
  A: This was a fairly difficult question! Surprisingly, there's not many references that describe the ...
facing side of the moon5/12/2007
  Q: The same side of the moon always faces us, therefore as the moon orbits around the Earth, it must ...
  A: The moon is "locked" into synchronous rotation with the earth, meaning that it always presents the ...
supernovae5/7/2007
  Q: what is meant by super navae?
  A: A supernova is a star which explodes violently. There are two main types. In one type, a very ...
Sloan Great Wall4/30/2007
  Q: It seems too unlikely that the formation of the Sloan Great Wall is due to coincidence. Is there ...
  A: The Sloan Great Wall is not a structure, as such, since the galaxies are not gravitationally bound. ...
No Direction to Find Big Bang4/30/2007
  Q: I read your explanation that there is no direction to specifically look to find the big bang. I ...
  A: You've hit the nail on the head. Yes, we should see evidence of young galaxies when we see the ...
Big Bang and Blackholes4/28/2007
  Q: Gort I was reading your answer about the blackhole universe theory, and I was wondering if it would ...
  A: For not knowing much about astrophysics, you just came up with one of the current theories on the ...
SINGULARITY4/20/2007
  Q: Sir I want to ask that according to many models of universe there was a singularity at the ...
  A: This question is currently being studied by some of the best minds in physics. You're right - ...
speed of light4/18/2007
  Q: in special relativity speed od of light is constantn & works as a linkage of connecting space & time ...
  A: You're probably referring to Einstein's statement that "according to the general theory of ...
Big Bang4/14/2007
  Q: In the book "Death by Black Hole, Dr. Tyson states that at the Big Bank plus 1 second, the universe ...
  A: Very observant! I'll have to qualify my remarks with the fact that I haven't read Tyson's book. ...
heliosheath4/11/2007
  Q: i just heard about the heliosheath. i have two questions if you will, (not very easy ones, i fear) ...
  A: We've "known" about the heliosheath (theoretically) at least from the late 1950's. In 1957, S. ...
Supernovae4/1/2007
  Q: I've been reading up on the Permian-Period extinction theory and was wondering how close a supernova ...
  A: There's been considerable research into this lately. We'll look at it from two ways: The first is ...
BOL3/3/2007
  Q: Recently you considered a question i had ...
  A: You are correct - particles accelerated along field lines near a sunspot is essentially the same ...
What caused/came before the big bang?3/3/2007
  Q: Is it posible that as the universe ages black holes become more numerous and or grow larger & ...
  A: You've asked a very profound question. But the short answer to your question is "yes", what you ...
Variability of information2/28/2007
  Q: Gort, Over the decades as we read and learn about astronomy and physics one thing stands out and ...
  A: I agree with what the article points out. Especially in astrophysics. I sometimes tell my class ...
cosmology2/26/2007
  Q: If the Universe is fifteen billion years old and the furthest stars are fifteen billion light years ...
  A: I think the confusion stems from the familiar terms of "age" and "expanding". With the universe, ...
What Did I See?2/23/2007
  Q: I recently saw what appeared to be a normal star whose brightness intensified perhaps tenfold, then ...
  A: This is difficult to determine, but I don't think it was a star. If it was fairly low in the sky, ...
SUN2/21/2007
  Q: Why do Sun get brighter in Noon then in early morining?
  A: The sun appears brighter around noon because the sun's rays are most direct then. At noon, they ...
Big Bang2/16/2007
  Q: I know the scientific evidence for the Big Bang, but what I don't understand is why "we" see no edge ...
  A: The problem I think you're having is the name "Big Bang". A "bang" implies an explosion of ...
Neutron Stars2/13/2007
  Q: Prof. Gort, I have a question about what it would be like to be on a neutron star. Years ago in an ...
  A: What you heard is partially true. But it's even more astonishing that that. The average density in ...
"earth flares"2/11/2007
  Q: Do you think it's feasible that earth could produce "earth flares?" Like "solar flares" but these ...
  A: You've asked a very interesting question! I've not heard such a theory proposed before, but I've ...
Planet formation2/11/2007
  Q: When a rocky planet is forming, how do the pieces of rock "stick" to each other? In the 70's I heard ...
  A: The condensation process (in which planets were formed from the solar nebula) began to be studied ...
Observing Satellite by Naked eyes2/3/2007
  Q: Is it possible to see a satellite using our naked eyes. I recently saw an object in the sky in the ...
  A: Yes, you can see many satellites with your naked eyes. None of them (to my knowledge) have exterior ...
JUSTIFY The Big Bang1/12/2007
  Q: Scientists say the universe is expanding. That's their evidence for the big bang. But scientists now ...
  A: If you want me to justify the Big Bang, then you've asked the wrong person. If, on the other hand, ...
What Did I See????1/8/2007
  Q: I witnessed something which has puzzled me for many years. Now that we have the internet, I ...
  A: This is a pretty difficult one, but I'll do my best. First of all, I can confirm what it was not. ...
Multiverse?12/27/2006
  Q: Gort. I have a question related to the idea of a multiverse. I realize this is probably considered ...
  A: You've asked a very interesting and intriguing question. But one we may never know the "answer" to. ...
super nova12/19/2006
  Q: what happens if the core is able to produse iron before imploding
  A: If a star is more massive than about 8 times the solar mass, it is able to produce iron through ...
aurora borealis (sp?)/ Northern Lights12/15/2006
  Q: I saw today on the news that the northern lights may be seen in Kansas tonight. I need to know what ...
  A: That's very difficult to predict. It depends on what materials were ejected by the sun, how fast ...
neutron stars/ pulsars12/14/2006
  Q: 1. Are neutron stars and pulsars the same? 2. Are black holes a hole in space/time, or is there a ...
  A: To answer your first question, all pulsars are neutron stars (currently accepted models!), but not ...
"we are stardust" and "we are nuclear waste12/14/2006
  Q: hey James,Can you help me out with the quotes "we are stardust" and "we are nuclear waste" in terms ...
  A: According to the currently accepted theory of stellar evolution, we are both "stardust" and "nuclear ...
Astrology?12/8/2006
  Q: What is the next month during which a full moon will not be seen in Wilmington, DE?
  A: Because the lunar month (the time between successive new moons or full moons) is 29 days, 12 hours ...
A question about black holes12/2/2006
  Q: I am a student from Israel. I'm doing a school project about "Black Holes", and i have a question I ...
  A: In the center of a black hole, there is mass. According to Einstein, all mass distorts ...
hi11/24/2006
  Q: i was just wondering how many times have you seen black holes?and have you ever seen Ufo's?
  A: I've never seen a black hole. No one has. They're black and so they're invisible. But we can see ...
Astronomy11/5/2006
  Q: Why can we never see a full moon in the sky at mid-day?
  A: The full moon means that the sun is on the opposite side of the earth, illumimating the moon. If ...
Speed10/26/2006
  Q: I know the earth travels about 67.000 mph around the sun to make it all the way around each year. ...
  A: There is new data coming in on this all the time, mainly from the Hippararchus satellite. But a ...
big bang and age of everything10/9/2006
  Q: How can astronomers say they are looking at the universe only a few billion years old if we were ...
  A: You've asked a very profound question. And one I've not seen raised very often. I wish I had an ...
Multiple universe10/6/2006
  Q: Are we the only universe in space, it seems this would be the same as assuming we are the only ...
  A: Well, there's nothing in any known physical law which would prohibit multiple universes. And ...
Black Holes and the Big Bang9/30/2006
  Q: If I understand correctly, a black hole results when a star more that a few times the mass of our ...
  A: Your idea of black hole formation is essentially correct, except the star starts with a mass over ...
the Sun9/18/2006
  Q: What is the real name of the sun?
  A: The Sun is the only English name for the star which warms our solar system. The term is derived ...
Asteroid Belt8/28/2006
  Q: Does this theory hold any scientific merit, if not why? ...
  A: You've asked the right person. Many scientists would discount this theory as "outside the ...
Black hole8/27/2006
  Q: I have many questions about Astronomy but I will ask some few only: 1) What is the end of a black ...
  A: 1) If you're asking whether a black hole will have an end and eventually die, the answer is ...
Photographing the earth from space12/31/2005
  Q: Howdy do. If one were in geostationary orbit, hanging out with all the cool satellites, and one were ...
  A: Since the geostationary satellite is 26,000 miles up, and the earth is about 8000 miles in diameter, ...
Measuring Degree of Ellipticity12/29/2005
  Q: How can I quantify the degree of ellipticity of various oval shapes or orbits? Can I measure the ...
  A: Yes, you can measure the widest point (call this length 2a) and the narrowest point (call this ...
Cosmology9/2/2005
  Q: if the Universe is actually open in geometry and there is an end to it (far beyond our horizon)then ...
  A: You're asking something beyond all scientific knowledge. But if you're asking for a guess, I can ...
Space9/1/2005
  Q: 1) Do all galaxies rotate counterclockwise? 2) How fast is our Solar System rotating around the ...
  A: 1) No, galaxies rotate in random directions and orientations. By the way, the appearance of a ...
moon8/27/2005
  Q: Can the moon at times be seen by both sides of the world at the same time? Since I have seen it ...
  A: The way you phrase the question, I'd have to say "sometimes". If we see the moon just rising in the ...
space8/25/2005
  Q: None of the Galilean satellites have an atmosphere that is anything like as substantial as Titan, ...
  A: You've asked a very interesting question, and one subject to much current research. As you probably ...
astrophotography8/19/2005
  Q: i want buy a digital camera for astrophotography but my budget is limited, is it suitable to buy ...
  A: I'm not up on all the latest equipment, but you want to ensure that there's a "bulb" mode and good ...
Moon's Orbit8/17/2005
  Q: Man made "space junk" as it orbits earth eventually enters back into the earth's atmosphere and ...
  A: You've asked an extremely difficult question, requiring a good deal of orbital mathematics to prove. ...
mass, speed and gravity8/2/2005
  Q: if a large object was traveling through space at the speed of light or more, will it hae gravity? ...
  A: That's an interesting thought question, but it might not be possible to test, because Einstein said ...
Mars7/26/2005
  Q: I received this email yesterday. CLOSE ENCOUNTER WITH MARS Never again in your (or my) ...
  A: Yes, that was an old clipping from 2003. In August, 2003, Mars made its closest approach to Earth ...
historical accounts7/23/2005
  Q: I'm a recent college grad. I was talking a lifer friend of mine (he's been in college for 6 years) ...
  A: A. For the first question, I am not familiar with the earth being "one day behind". From a ...
Void7/21/2005
  Q: Do we have a hypothesis or deduction with regard to what could be a void (something that lacks ...
  A: First, I'll give you my view (based solely on an opinion and not much research), but then I'll give ...
Astronomy, Moon Orbit7/20/2005
  Q: Since I was a child I've noticed that the moon rises & sets pretty much between the same positions ...
  A: Good observation! As you know, the ecliptic is the path the sun appears to follow. Since it's ...
Astronomy7/17/2005
  Q: im trying to buy a telescope for about 100 +- $170 i found two but im not sure which one to buy. ...
  A: The most important part of any telescope is that it is actually used. So a telescope must be easy ...
seeing back in time7/12/2005
  Q: When we look at distant galaxies (or other distant objects), we see them as they were a very long ...
  A: Mike, That message was a follow-up to the original message. Perhaps you didn't receive it. But ...
Solar physics7/5/2005
  Q: I was recently at a site called: The Surface of The Sun ...
  A: This is exactly the sort of question that "AllExperts" is all about. I'm very glad you asked me. ...
Travelling to Mars at the speed of light6/20/2005
  Q: How long would it take, on average (considering that Earth and Mars might be in different stages of ...
  A: This is a very difficult question to answer "correctly", and much depends on what you mean by "on ...
galectic formation6/18/2005
  Q: GALACTIC SEEDS The rapid formation of galaxies has been problematical to cosmologists. The ...
  A: First, let me preface my remarks by saying that my expertise is not in cosmology, but I am an ...
The Hubble Telescope6/14/2005
  Q: Where is the Hubble Telescope, sir?
  A: The Hubble Telescope orbits the earth at an average altitude of about 352 miles. If you'd like to ...
What colour are the planets?6/13/2005
  Q: 1. What colour are the eight planets: mercury, mars, jupiter, venus, neptune, saturn, pluto, and ...
  A: 1. I think the best site I can recommend is ...
Mars6/11/2005
  Q: Gort, Is it correct, or is it a hoax, that ...
  A: Richard, I forgot to mention - this is considered the most favorable period for telescopic ...
Shoemaker Levy6/9/2005
  Q: I have read much of the impact of Shoemaker Levyon Jupiter, what I want to know is... How big were ...
  A: About 20 large fragments (which were seen and identified from space and ground observatories) ...
Magnitude5/31/2005
  Q: How can we measure magnitude of stars by a CCD camera? And how can we precisely do it? Sincerely.
  A: Glad to see you're interested in pursuing some real science! The short answer is easy, but the ...
Balance point betwen earth and moon5/26/2005
  Q: I recall several years ago reading about three points in space between the earth and the moon where ...
  A: I think you're referring to LaGrangian Points. There are five such points in the earth-moon system. ...
The line5/19/2005
  Q: my teacher was talking about our galaxy and how the earth moves very slowly over a line or some ...
  A: I'm not quite sure what you teacher was referring to, but I'll try and help. The sun is located ...
Recently Polarized Sunlight5/13/2005
  Q: I and some acquaintences have recently noticed that around sunrise and sunset sunlight seems to be ...
  A: Good observation! I'm not sure what's causing it - it could be a volcano, additional air pollution ...
Earth and Planets4/22/2005
  Q: If the Earh stopped revoling around the Sun would the other planets in our solor system be sffected?
  A: If the Earth stopped revolving around the Sun (and crashed into the Sun because it wouldn't be in ...
earth and sun4/22/2005
  Q: have you ever been in space? because i have a question for you. What would happen if the earth ...
  A: I have never been in space. If the Earth stopped revolving around the Sun, the Earth would not go ...
Earth and Sun4/22/2005
  Q: If the Earth stopped revolving around the Sun would the Earth slowly go closer to the Sun? Also ...
  A: If the Earth stopped revolving around the Sun, the Earth would not go SLOWLY closer to the Sun, but ...
space adventure4/20/2005
  Q: Have you ever been into space? If yes please discrab you exerinces and fealing about what you saw in ...
  A: No, I've never been in space. But I did apply to the Canadian Astronauts Program. Thousand of ...
moon4/20/2005
  Q: If you cut the moon in half what would it look like?
  A: The moon does not have a liquid core like the earth does. It has a thin layer of dust on the ...
Moon4/20/2005
  Q: What would happen if the moon stopped revolving around the earth? How would our tides be affected? ...
  A: If the moon was not there at all, the tides would be one-third as high (since the moon causes ...
Earth's rotation4/19/2005
  Q: What would happen if the earth stopped rotating gradually?
  A: Sarah, The days would get longer than 24 hours, until one side of the earth would always be day, ...
Astronomy4/14/2005
  Q: "What night is the longest night of the year?" Thank you very much! A.Vafa
  A: In 2005, the "Winter Solstice", or the northern hemisphere tilted the greatest amount away from the ...
strange question4/8/2005
  Q: My question is going to sound a little crazy but please If u can answer it, Then please do. ...
  A: Hassan, There are no crazy questions - only crazy answers! And I hope this isn't one of them. The ...
galaxy question4/2/2005
  Q: Is there a mathematical equation that represents a spiral galaxy such as the milky way? If so, ...
  A: The best source I know of which can help answer your question is a book entitled "Spiral Structure ...
Astronomy/solar system12/31/2004
  Q: Is "What is the difference between Earth's moon and Pluto's moon" a project i can do for a ...
  A: A science fair teaches "Independent research" (like a real scientist does). So look up "Charon" and ...
Aviation and Space Science12/30/2004
  Q: My organisation [NYDT] set up the Africa Space School for schools in [Southern] Africa. We have an ...
  A: I would be most happy to participate. Currently, I am a Professor of Astrophysics at the University ...

All Questions in This Category

Astronomy

All Answers


Answers by Expert:


Ask Experts

Volunteer


James Gort

Top Expert on this page

Expertise

Questions on observational astronomy, optics, and astrophysics. Specializing in the evolution of stars, variable stars, supernovae, neuton stars/pulsars, black holes, quasars, and cosmology.

Experience

I was a professional astronomer (University of Texas, McDonald Observatory), lecturer at the Adler Planetarium, professor of astrophysics, and amateur astronomer for 42 years. I have made numerous telescopes, and I am currently building one of the largest private observatories in Canada.

Publications
StarDate, University of Texas, numerous Journal Publications

©2017 About.com. All rights reserved.