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visits member for 3 years, 4 months
seen Sep 22 at 18:34

Sep
27
comment How long does it take to travel 36 light years with tolerable acceleration and deceleration?
@FlorinAndrei: It gets shorter relative to earth but for the rocket and the people inside, everything will be just fine. They have other things to worry about though, for instance, to avoid being turned into cosmic goo by near-light speed protons hitting them on the way.
Sep
27
comment Are there planets that do not rotate on their axis?
@Zassounotsukushi: Angular velocity and angular momemtum are still measured w.r.t. a frame of reference. Even intrinsic angular momentum depends on the frame of reference. Correct me if I am mistaken.
Sep
27
comment Are there planets that do not rotate on their axis?
@Zassounotsukushi: I think it is incorrect to say that rotation does not require a frame of reference. It does, otherwise, you are implicitly assuming an absolute reference frame (i.e., aether).
Sep
17
comment Are there planets that do not rotate on their axis?
I still don't understand what it means for something to "not rotate". Nor rotate relative to what frame of reference? The stars in the background are actually moving.
Sep
15
comment Why do we always see the same side of the Moon?
I made an error above. Only if we stay on the line passing thru the centres of earth and moon do we really see the same side.
Sep
15
comment Why do we always see the same side of the Moon?
Technically, we don't always see the same side of the moon. It depends on the location on earth we observe from. However, from the same point on earth, we do see the same side of the moon.
Sep
14
comment If the Earth didn't rotate, how would a Foucault pendulum work?
'Didn't rotate' relative to what frame of reference? Tidally locked with the sun is one possibility, as is the possibility that it does not rotate w.r.t the milky way centre, or maybe you mean a particular galactic cluster? Even the distant stars and galaxies are moving, so there seems to be no "universal stationary frame of reference".
Sep
13
comment What can the D-Wave quantum computer do?
@joe Fitzsimons: true. My bad. I meant NP. Though, the first part of the claim is not entirely wrong. NP complete is part of NP.
Sep
12
comment What can the D-Wave quantum computer do?
If it can solve one NP complete problem then it should be able to solve any NP complete problem, including factoring. I highly doubt it can solve an NP complete problem though.
Sep
11
awarded  Scholar
Sep
11
accepted Particle antiparticle annihilation-do they have to be of the same type?
Sep
11
awarded  Student
Sep
11
asked Particle antiparticle annihilation-do they have to be of the same type?
Sep
8
comment What is Energy made of?
How can matter be converted to trait of matter? Can a person be converted to age? It just does not make sense. Energy must be made of something. Or else mass itself is not made of anything.
Sep
7
awarded  Supporter
Sep
7
comment Confusion with infinity and time
I found this question to be interesting. It is as philosophical as "is the universe infinite".
Sep
7
asked What is Energy made of?
Aug
31
comment Are our telescopes capable of taking actual images of brown dwarfs?
If you mean "optical telescopes", the probably no. but I think infrared and larger wavelength telescopes should be able to "see" brown dwarfs.
Aug
31
comment Curvature of the Universe imaginary?
Pythogorean theorem is a theory (evident from from the word "theorem") of Euclidean space which is flat. It does not say that the real universe is Euclidean.
Aug
31
comment Galaxies seen from Earth
I would assume so. I didn't see the difference between the first and second question except the time difference. Please clarify