| Subject | Date Asked |
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| Electragnetic fields | 10/23/2009 |
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) ...
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| Tokamak | 10/21/2009 |
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 ...
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| Science Fair | 10/6/2009 |
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 ...
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| eddington limit | 9/5/2009 |
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 ...
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| Gravity, escape velocity | 7/21/2009 |
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 ...
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| Gravity, escape velocity | 7/21/2009 |
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 ...
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| solar flares | 7/19/2009 |
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 ...
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| Einstein | 7/19/2009 |
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: ...
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| The supposed "Alignment" of 2012 | 7/1/2009 |
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 ...
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| Big Bang | 6/16/2009 |
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 ...
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| measure of movement in space | 6/10/2009 |
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 ...
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| dark matter | 6/9/2009 |
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 ...
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| Cat's Eye Nebula | 5/22/2009 |
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 ...
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| Optics | 5/19/2009 |
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 ...
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| Atom formation | 5/13/2009 |
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 ...
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| Nanotechnology | 5/9/2009 |
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 ...
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| The first second of the big bang | 5/6/2009 |
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 ...
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| Nanotechnology | 5/5/2009 |
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 ...
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| astrophysics | 4/29/2009 |
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. ...
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| astrophysics | 4/29/2009 |
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 ...
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| A HYPOTHETICAL QUESTION | 4/28/2009 |
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 ...
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| Energy in physics | 4/23/2009 |
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 ...
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| relativity | 4/19/2009 |
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 ...
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| relativity | 4/17/2009 |
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. ...
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| special relativity | 4/16/2009 |
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 ...
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| Relativity | 4/2/2009 |
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 ...
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| work | 3/19/2009 |
Q: why when we calculated the work we multiplied force * distance not F/D i.e division what is the ...
A: It's just the definition of work. It's actually a specific definition for a constant force in a ...
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| Solar System Model | 3/18/2009 |
Q: I'm interested in creating a mathematical model of the solar system via a computer program. But I'd ...
A: I don't mean to rain on your parade here, but I'm not the bearer of good news for this hobby of ...
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| about the relation between plannets and stars | 3/10/2009 |
Q: sir..why mostly all the plannets in solar system revolve eleptically around the sun but not ...
A: To move in a perfectly circular orbit a planet would have to form with exactly the right velocity ...
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| How are neutrinos detectected if they are ghost? | 3/9/2009 |
Q: I recently watched a supernova documentary and it was stated that during the collapse of stars to ...
A: On average, yes, they do. But the sheer number is staggering (trillions pass through your body each ...
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| Big band and Space-time | 2/18/2009 |
Q: I've just read the question asked about the Big bang and it being the same in all directions. ...
A: No, the Earth is not the center of the universe. Since the Big Bang defines all of space, it will ...
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| looking 14 billion years towards the big bang | 2/10/2009 |
Q: I've been interested in the universe and the way it works since i was a boy (now 37!). There is ...
A: The big bang did happen in every direction you look. All the matter you see was inside it, no ...
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| (Extremely) Theoretical Physics | 12/19/2008 |
Q: I'm not sure if you'll be able to answer this, if not could you please point me to someone that ...
A: It's not extremely theoretical. Like the photon, the graviton would be its own antiparticle, ...
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| Regarding Iron | 12/2/2008 |
Q: I read that Iron is an extra-terrestial element. Is that true? Are there other elements in earth ...
A: A very few of the lightest elements were created during the big bang, but all of the heavier ones ...
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| Infinity | 12/1/2008 |
Q: All my life I have read or heard that space/time is infinite. Since I can't fathom the idea, I just ...
A: This is an unanswered question in science, depending greatly on the curvature of spacetime itself ...
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| Relativity | 11/23/2008 |
Q: How does Einstein's theory of relativity apply in space?
A: You'll need to be more specific. How does it not apply in space? Relativity applies to the ...
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| light | 11/21/2008 |
Q: sir plz tell me that which gasses are filled in flourescent tube light.also give the energy level ...
A: It's generally mercury. Look below for a table, as far as a diagram you'll have to find a proper ...
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| please help me | 10/28/2008 |
Q: Mr. nelson, Can you please give me the answer to this question if I got it wrong and could you ...
A: Perhaps the question is poorly posed. Did they mean arc ACB instead of ABC? If it asked arc ACB I ...
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| Hawking's Concession | 9/26/2008 |
Q: As a layman, Stephen Hawking's concession regarding the black hole information loss problem was ...
A: Alternate universes are purely speculative. There's no experimental evidence to support them and ...
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| MS | 9/25/2008 |
Q: Sir, I have done my B-tech in mining eng. and i have a great interest in astrophysics.I would like ...
A: Astrophysics is an easy subject to read a lot of popular literature about but a very, very difficult ...
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| Logical Answer | 9/4/2008 |
Q: While doing a physics problem dealing with the centripetal acceleration of a pulsar, I calculated ...
A: Well, the minimum pulsar radius is about 10 km (circumference about 31 km) and the maximum pulse ...
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| photon energy of a blackbody spectrum | 8/27/2008 |
Q: The approximate mean photon energy of a blackbody spectrum which is emitted by an object at a ...
A: There are two different things here. The average energy of a blackbody photon is 2.7 kT where T is ...
|
| speed of light | 7/31/2008 |
Q: I was wondering, did Einstein say NOTHING could go faster than the speed of light (particles etc. ...
A: Neither. Relativity determines that nothing with mass can accelerate to the speed of light because ...
|
| magnetic poles | 7/16/2008 |
Q: How can you find out which is the north-seeking and the south-seeking pole of a magnet? I know that ...
A: Yes and no. In that you don't need an external magnetic field to move the magnet, you can use the ...
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| termo | 7/10/2008 |
Q: The differance in the temperature of the metales leads to the differance in electerical charge. can ...
A: Yes we can, and some devices and spacecraft are powered this way already. However, the efficiency ...
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| White holes -- my favorite astronomical object | 7/3/2008 |
Q: What about white holes makes their existence impossible? A white hole is the opposite of a black ...
A: White holes are a mathematical solution to Einstein's field equations involving no matter, hence ...
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| White holes -- my favorite astronomical object | 7/2/2008 |
Q: What about white holes makes their existence impossible? A white hole is the opposite of a black ...
A: It's nice to give it a name that sounds opposite, and ask why it can't exist, but you have to come ...
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| egg drop w/ restrictions | 6/20/2008 |
Q: I am a high school librarian taking a design course at a local college. Our final assignment is to ...
A: Energy must be dissipatedBy crumbling toothpicks. It doesn't matter how smashed your design looks ...
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| Gravity, escape velocity | 6/5/2008 |
Q: Steve! I promise my question won't be as esoteric as "quantum gravity", haha. I've been reading a ...
A: When I said it would fall and burn up, I didn't assume you meant an impossible rocket that could ...
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| Gravity, escape velocity | 6/4/2008 |
Q: Steve! I promise my question won't be as esoteric as "quantum gravity", haha. I've been reading a ...
A: You don't seem to have calculated the scale of the distance you're talking about. Use this handy ...
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| "escape velocity" | 6/3/2008 |
Q: Steve! I promise my question won't be as esoteric as "quantum gravity", haha. I've been reading a ...
A: If you design an F-16 to fly without the need for oxygen, it would be a rocket. Technically, you ...
|
| Gravity | 5/13/2008 |
Q: What is the smallest scale at which the force of gravity has been measured or detected, in terms of ...
A: That is basically what I mean, yes. Also, the lack of observation of the graviton is indeed one ...
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| Gravity | 5/13/2008 |
Q: What is the smallest scale at which the force of gravity has been measured or detected, in terms of ...
A: Wow...the scope of the questions.... The smallest scale at which the force of gravity has been ...
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| the sun | 4/17/2008 |
Q: A fireman friend asked me this question yesterday and it has been driving me mad, so hopefully you ...
A: The sun doesn't burn oxygen like a flame to create energy with a chemical reaction like an ...
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| time dilation at relitvistic speeds (badly spelt) | 2/9/2008 |
Q: i had an argument with my physics teacher when doing a level physics in the 90's i failed and gave ...
A: Basically, as you accelerate to high speeds you change your inertial reference frame and thereby ...
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| galactic movement | 2/9/2008 |
Q: just a silly question from a man whose interested.. if the universe is expanding and the galaxies ...
A: Galaxies are still subject to local gravitation within their cluster and do move in different ...
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| jupiter's mass | 2/7/2008 |
Q: My question is considering Jupiter size and though it's distance from the sun it has been shown that ...
A: Not likely, compared to the massive forces inside the Sun and the effect of its own magnetic fields ...
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| Star supernova | 1/28/2008 |
Q: A star that suddenly explodes is called a supernova. Looking at the events of supernovas in the past ...
A: It's possible, supernovae that we see from very far away are transmitting light billions of years ...
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| Possible Earth re-entry | 1/18/2008 |
Q: Would it be possible to slowly lower a very long cable down to earth from the Thermosphere? Would it ...
A: Short answer: you're talking about a space elevator, which is technically possible, but the ...
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| atomics particles | 1/16/2008 |
Q: What are the diffrences of a neutron and an antineutron ?
A: And anti-neutron is made of anti-quarks instead of quarks. It has an opposite magnetic moment. ...
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| Vacuum in Space | 1/4/2008 |
Q: What is the extent of the vacuum in space, to what degree has it generally been measured? I ...
A: The vacuum of space varies greatly. It goes down to about 4 particles per cubic meter in ...
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| Planet X | 12/30/2007 |
Q: I read where NASA discovered Planet X in Dec. 1983 with the IRAS telescope. The story was published ...
A: This is too easy: No cover-up. Why? I know you can figure this out for yourself, but for ...
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| Comet Holmes | 12/20/2007 |
Q: It seems that many are questioning the brightening of Comet Holmes. I find it hard to figure how the ...
A: According to astronomer estimates, it only lost about 1% of its mass: ...
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