Recent content by azerbajdzan

Is it possible in real life, that the energies of incident and reflected photons are the same (f1=f2) if reflected photon went exactly the opposite direction to the direction of incident photon? ...it would mean that the rest mass of the body after collision have been decreased compared to rest...

So free electron (not inside atom) cannot absorb photon without emitting some other photon? Is it this you are trying to say?

I know that absorbing a photon increases the mass, but I was not sure which mass - the rest mass or relativistic mass (mass at non-zero speed)... But yes, it now makes more sense when I replace m0 with m1 on the right side of both equations. Now another example... The photon reflects exactly...

Hello, Suppose that an object of rest mass m0 travels to the right with speed v1. A photon of frequency f also travels to the right and hits the object. The photon is fully absorbed by the object and then the object travels to the right with the (unknown) speed v2 after collision. Now, the...

Thank you for your detailed explanations. I can follow all of them. I should have noticed that the definitions of all parameters, constants and columns are displayed when mouse pointer is held above the "blue question-marks". I tried to click on them and nothing happened. I use Opera as web...

Thank you for your comment. I have got some questions. What is Dnow, Dthen, Dhor? I can not see a definition of it on that page. I guess diameter of universe? If so what is meant by "then" (when then?), "hor", what is meant by "now"? There is only one "now", bu in the table there is one "now"...

So bigger or less? Your post confused me even more. This is quote from this link http://www.setterfield.org/000docs/redshift.htm : "Edwin Hubble showed in 1929 that the more distant the galaxy, the larger this "redshift"." So it is like I said according to this article.

Many prominent physicists admit that it is possible that "dark energy theories" could be wrong, although for now it is the most satisfying theory. (Like Newton's theory was/is imprecise in some situations, so in strict sense it was/is wrong in general) Example: Perihelion precession of...

I have not said that dark matter has something to do with expansion. It is dark energy that causes expansion by today's physics. I just mention dark energy and dark matter together as an examples that when people are not able to explain something then they invent some terms/ideas to support...

All current observations are for me not enough convincing to say that universe is expanding at increasing rate. And then think up some dark matter and dark energy to support this idea. More likely it is that there is no dark matter (except black holes, faint stars and similar common objects)...

I understand it... and I read many articles about it... on wikipedia and others. But this is question that I still do not understand, that is why I am asking. I understand this. But then they say, that more distant objects have bigger redshifts. More distant means more back in time. So I explain...

To me the redshift at particular time only means that universe is expanding not that it is expanding at increasing rate. The evidence of accelerating expanding would be if redshift increases with time. But it looks to me that the difference between redshift in, say, 2012 and in 2013 do not...

Universe appears to be expanding at an increasing rate. What measurements were performed to support this idea? My current understanding is that in general redshift of distant stars/galaxies is increasing with time. So to me the measurements may look like this: We choose one star...

Is it like this for the second case? (see picture)

We are interested in pressure along green axis in the first picture and along orange axis in the second picture. Air pressure is constant everywhere. For the first case: under water surface: p = patm + ro.g.h patm = 105 Pa = 105 kg.m-1.s-2 ro = 103 kg.m-3 g = 10 m.s-2 h =...