| Subject | Date Asked | Expert |
|
| Follow-up solution | 11/5/2009 | Philip A. Stahl |
Q: Okay, I think I have worked this out, but can you tell me if it’s right? From the link you gave in ...
A: Congrats! You have it correct! The key to the solution was in seeing that, after you obtain the ...
|
| Binary star problem | 11/3/2009 | Philip A. Stahl |
Q: Can you help with this problem? A visual binary has a period of 100 years, and the semi-major axis ...
A: This looks like a fairly basic HW problem, so I will just get you oriented to solving it yourself. ...
|
| Relative and Absolute Time | 11/3/2009 | Philip A. Stahl |
Q: I have no training in astrophysics and very little knowledge about it. However, I am an interested ...
A: Okay, you have really two separate issues and I don't want to get them confused - so will stick with ...
|
| astrophysics/ black hole theory | 10/31/2009 | Philip A. Stahl |
Q: I am really in need of help on a theory I am coming up with. I have found most of my answers that ...
A: There are several problems with your theory. Let's look at it from the aspect of stellar ...
|
| Electragnetic fields | 10/23/2009 | Steve Nelson |
Q: I was wondering whether the electragnetic fields around people and animals have been proven to emit ...
A: You mean electromagnetic. Electromagnetic fields around people are 1) extremely weak and 2) ...
|
| Tokamak | 10/21/2009 | Steve Nelson |
Q: I am deeply interested in nuclear fusion. I have read, that in Tokamak systems the D-T plasma fuel ...
A: Tokamak systems are huge. The sheer level of x-rays you're talking about would require ridiculously ...
|
| Science Fair | 10/6/2009 | Steve Nelson |
Q: Im sorry to admit this - even to myself - but that science fair project you gave me before was just ...
A: Well it's going to have to be drastically simplified at this point, because my other project was ...
|
| eddington limit | 9/5/2009 | Steve Nelson |
Q: here is my question. If you can help me I will really appreciate... I am confuse about how can I ...
A: This really sounds like your astrophysics homework, so I'm going to only give you my opinion on how ...
|
| cmbr | 8/6/2009 | Philip A. Stahl |
Q: sir, what is CMBR?
A: "CMBR" refers to the *cosmic microwave background radiation*. That is the 2.7 K temperature "relic ...
|
| boundry of universe | 8/4/2009 | Philip A. Stahl |
Q: sir, what does latest research guide on the subject i mentioned above? is there any boundry of ...
A: There is no firm answer yet to whether the universe has a "boundary". This is because more ...
|
| Gravity, escape velocity | 7/21/2009 | Steve Nelson |
Q: Sir, I'm just an old guy (69) browsing and came across your answer to this question regarding ...
A: Due to people who would rate a question badly just because they didn't want the truth or who would ...
|
| Gravity, escape velocity | 7/21/2009 | Steve Nelson |
Q: Sir, I'm just an old guy (69) browsing and came across your answer to this question regarding ...
A: A jet does indeed have the massive specific impulse one needs to reach orbit, with a couple of big ...
|
| solar flares | 7/19/2009 | Steve Nelson |
Q: I have seen images of solar flares sending ripples across the surface of the sun (sunquakes). Is ...
A: Well, there are certainly waves inside the Sun, but you don't get ejection in there because there's ...
|
| Einstein | 7/19/2009 | Steve Nelson |
Q: Did Albert Einstein graduate from elementary school (or the equivalent)? Did he graduate from high ...
A: Yes, he earned all his degrees and his life is accurately chronicled in his wikipedia entry: ...
|
| The supposed "Alignment" of 2012 | 7/1/2009 | Steve Nelson |
Q: I read an article stating that the alignment of the earth, moon and sun on the 2012 solstice and the ...
A: Alignment of arbitrary orbit planes? We actually came closer to "alignment" in 1998 than we will in ...
|
| Big Bang | 6/16/2009 | Steve Nelson |
Q: Steve, My (amateur) understanding is that the theory of "inflation" was developed to explain the ...
A: But there's non-uniformity that we observe with WMAP and so on. We need inflation to explain baryon ...
|
| measure of movement in space | 6/10/2009 | Steve Nelson |
Q: I watch a lot of nasa channel and I was wondering this....Speed of orbiting craft are giving quite a ...
A: No, we travel through space relative to the Sun and center of the Galaxy at much higher velocities ...
|
| dark matter | 6/9/2009 | Steve Nelson |
Q: Steve, Will the new model, which doubles existing estimates for the size of super massive black ...
A: No, actually. We knew galaxies had massive centers, it's the increase in speed of rotation ...
|
| Escape velocity | 5/25/2009 | Philip A. Stahl |
Q: I've always been told Earth's escape velocity is 25,000 mph, but never understood WHY? If a space ...
A: Well, there is a non-math explanation but: a) it won't eliminate fully your 3,000 mph belief (that ...
|
| Escape velocity | 5/24/2009 | Philip A. Stahl |
Q: I've always been told Earth's escape velocity is 25,000 mph, but never understood WHY? If a space ...
A: You probably have never understood escape velocity - the concept, because it was always presented to ...
|
| Cat's Eye Nebula | 5/22/2009 | Steve Nelson |
Q: I recently saw an amazing photo of the Cat's Eye Nebula and read that it is considered to be one of ...
A: First, keep in mind that I'm not an astronomer. The physics of what's going on inside is part of my ...
|
| Optics | 5/19/2009 | Steve Nelson |
Q: 1-Why is light bent by a gravitational field?And how? 2-What is the theoretical backing behind the ...
A: Light isn't actually bent, light travels in a straight line. It's space that's bent, meaning a ...
|
| Atom formation | 5/13/2009 | Philip A. Stahl |
Q: I was browsing through the WMAP website and found this time line of our universe. ...
A: You are correct that the universe had to cool down, a lot actually, in order for atoms to be able to ...
|
| Atom formation | 5/13/2009 | Steve Nelson |
Q: I was browsing through the WMAP website and found this time line of our universe. ...
A: Well, you have a small misunderstanding. The "Dark Ages" didn't mean that the universe was empty of ...
|
| Solar plasma instabilities | 5/10/2009 | Philip A. Stahl |
Q: I am interested in the sort of plasma instabilities that occur in solar conditions (say before solar ...
A: Yes, there are a number of instabilities associated with solar plasma, mostly defined in terms of ...
|
| Nanotechnology | 5/9/2009 | Steve Nelson |
Q: What do you think/know about nanotechnology? what does it mean to you? Also, What is your ...
A: The specific things you're asking about aren't really nanotechnology that a physicist would know ...
|
| The first second of the big bang | 5/6/2009 | Steve Nelson |
Q: I watched a documentary recently which explained the reason why we see background radiation ...
A: Be careful with the word "fact." It's misleading, and generally misused when dealing with physics ...
|
| Nanotechnology | 5/5/2009 | Steve Nelson |
Q: What do you think/know about nanotechnology? what does it mean to you? Also, What is your ...
A: I know a good bit about nanotechnology, it's an incredibly general term. It usually refers to ...
|
| astrophysics | 4/29/2009 | Steve Nelson |
Q: I have a question about projectile motion in outer space. Since space is virtually a perfect ...
A: Yes, because of the orbital motion, they would radiate away ridiculously tiny amounts of energy. ...
|
| astrophysics | 4/29/2009 | Steve Nelson |
Q: I have a question about projectile motion in outer space. Since space is virtually a perfect ...
A: No, once you set it and its gravitational field in motion you're done accelerating the object and ...
|
| A HYPOTHETICAL QUESTION | 4/28/2009 | Steve Nelson |
Q: Q 1: How the universe would like from the point of view of a photon? Q 2: Special theory of ...
A: 1) It's moving at the speed of light, so the universe would be totally static as it would appear ...
|
| Energy in physics | 4/23/2009 | Steve Nelson |
Q: I was wondering if you could clarify something for me. I know that in physics energy means the ...
A: The problem here is that you've latched onto a somewhat simplistic definition of energy. Energy is ...
|
| relativity | 4/19/2009 | Steve Nelson |
Q: Steve, As I understand, brane theory includes an explanation for the big bang and "time" before. If ...
A: A cesium clock measures time by the oscillation of quantum states of a cesium atom interacting with ...
|
| relativity | 4/17/2009 | Steve Nelson |
Q: Steve, As I understand, brane theory includes an explanation for the big bang and "time" before. If ...
A: There are many theories which are currently untestable which will lead us to surprises in science. ...
|
| special relativity | 4/16/2009 | Steve Nelson |
Q: I have a few questions on special relativity. Are you able to answer questions regarding this topic? ...
A: This question could use some rephrasing. Outside his "time frame?" What does that mean? It's not ...
|
| Hall term-Hall MHD | 4/6/2009 | Philip A. Stahl |
Q: Can you elaborate on the meaning and significance of the "Hall term"? Also when is it important and ...
A: The "Hall term" arises in one electro-dynamic formulation of Ohm's law often used in solar work, and ...
|
| Relativity | 4/2/2009 | Steve Nelson |
Q: Respected sir I am Mukul of class 11, please explain in as short as possible How does general ...
A: Relativity says that the presence of matter warps the geometry of space itself. That destroys ...
|
| Theory of relativity | 4/2/2009 | Philip A. Stahl |
Q: Relativity says that an observer can be moving in any way and but it will always observe the same ...
A: Theories, once created or proposed - and which stand the test of time, don't get registered in ...
|
| Theory of relativity | 3/31/2009 | Philip A. Stahl |
Q: Relativity says that an observer can be moving in any way and but it will always observe the same ...
A: The "relative velocity formula" is actually an equation for the addition of velocities in a ...
|
| Theory of relativity | 3/30/2009 | Philip A. Stahl |
Q: Relativity says that an observer can be moving in any way and but it will always observe the same ...
A: Yes, and you can work it out using the relative velocity formula: thus, u = (v1 + v2) / [1 + ...
|
