Tag Archives: Universe

COBE – Our Place in the Universe

NASA launched the COBE satellite on 18th of November, 1989. The main purpose of the mission was the examination of the thermal spectrum and the flatness of the cosmic microwave background radiation.

Flatness is important in terms of the emergence of cosmic structures. If the background did not show any “grain”, then we could not know the origin of those material centers, which later the galaxies and galaxy clusters would develop from. COBE found those “ripples” of the cosmic background, which could start the build of these cosmic structures. This is therefore a clear success, confirming the currently most popular theory of birth of the Universe, the theory of Bing Bang.

Another confirming of the theory is also the result of the COBE mission. It turned out that the spectrum of the cosmic background radiation nearly perfectly matches the spectrum of the absolute black body radiation. That means that the Universe was in a thermal balance in that time. This of course raises more questions, in particular, in relation to the second law of thermodynamics: if the total energy was in the radiation field in thermal equilibrium with maximum entropy, than the heat death of Universe, – which was so often cited by the physicists of the 19th century, as the threat of future – will not come in the future, but already has occurred in the past.

There is a more interesting result of the COBE mission. A Doppler-effect is detectable in the frequency of cosmic background radiation. The radiation frequency shifts towards blue in one direction of space, and shifts towards red in the opposite direction. It is calculated from the amount of shifting, that the detector, which is Earth itself, moves in space with a velocity of 600 km/s.

And it raises very interesting questions. For we know – since Galilei and Einstein -, that absolute velocity has no meaning, if we speak about the speed of something, we should always point to the reference body, we mean the speed to. Now, however, here is a speed, which we measured without telling the reference point we used.

So is this an absolute velocity? In contrast with all we learned about the principle of relativity of Galilei and Einstein in the school?

The majority of the scientists reply to this, that it is compared to the speed of the background radiation, so there is no any absolute in it.

But the truth is not that simple. For what is that background radiation? This is an electromagnetic space of radiation, which fills the whole Universe. So this is not a reference point, or body, or any rigid object in the classical sense. This radiation space is absolute in the sense that it is accessible to all the observers of the Universe. All of them can measure their velocity referenced to the background, they can count the velocity referenced to each other from this, so an absolute frame of reference could be built with the help of this. In addition to, the temperature of the background decreases by the age of the Universe, so an absolute time scale is also can be constructed.

Though, there is a little problem with this absolute scale. Namely, that the local velocity of expanding could not be detected, but this could be expected from an absolute frame of reference. Now let’s take an object, which is – according to its distance and the Hubble constant – moving away from us with half speed of light because of the expansion of the Universe. If there is a true absolute frame of reference, then he can measure it referenced to the background radiation. This would result so drastic blue-, and red shift, that the cosmic background would seem radically different to him, than to us. But the background should be nearly the same for every explorer in the Universe, for if it were not, there would be a respected explorer in the Universe, and this would be a harder return of the geocentric view of world.

Let’s note that the absolute frame of reference is not the same as the respected explorer. The former is an electromagnetic background, the latter a material explorer, who would be selected as some kind of center of the expanding Universe.

The key question is that: when we can measure our velocity to the background radiation, so why are we unable to measure our speed which comes from the expansion of the Universe?

Michelson and Morley at the end of the 19th century did their famous experiment precisely because they wanted to show the movement of the Earth in relation to the hypothetical ether. The null effect led to the special theory of relativity. The COBE showed the movement of the Earth a century later, though not relatively to the ether, but to something very similar to it. If Michelson and Morley had executed the COBE measurements, would there be a theory of special relativity?

I think, not…

March 1, 2014.