Nucleosynthesis 2 10 9 K. . 4 10 8 K. Electromagnetic decoupling 3000 K. Forming of the galaxies. Birth of the Sun. Today 2.73 K. Visible. Gamma Rays. X-Rays. Ultraviolet. Infrared. Microwaves. Radio, TV. . 1s. 100s. 1000s. 10 6 y. 10 9 y. 10 10 y. .
Forming of the galaxies
of the Sun
Evolution of the temperature of the Universe
Electromagnetic Wavelength (metres)
O n t h e T r a c k o f M o d e r n P h y s i c s
In the beginnig ...
“If the world has begun with a single quantum, the notions of space and time would altogether fail to have any meaning at the beginning; they would only begin to have a sensible meaning when the original quantum had been divided into a sufficient number of quanta. If this suggestion is correct, the beginning of the world happened a little before the beginning of space and time.” Georges Lemaître
The Belgian priest Georges Lemaître was the first to propose, in 1927, that the Universe began with the explosion of a primeval atom. His proposal came after observing the red shift in distant galaxies. Two years later, Edwin Hubble made systematic measurements of the red shift. He found that distant galaxies in every direction are going away from us with speeds proportional to their distance.
Our Universe started somewhat 14.5 billion years ago. It took less than one millionth of a second to make disappear heavy quarks, one hundredth of a second to make protons and three minutes to make hydrogen and helium but 300,000 years to decouple the light from the matter.
“This is the most beautiful and satisfactory
explanation of creation to which I have ever
listened.” Albert Einstein
If You observe a picture like this on Your TV, do not
change the channel. This can be a hidden massage from
distant civilizations, and for sure 1/3 of this noise comes
from the Big Bang fossil radiation.
The fossil radiation
When the temperature of the primordial plasma was low enough to allow electrons stick to nuclei, the Universe become transparent for light and the radiation decoupled started to wander around the Space. In the adiabatic expansion this radiation cooled down. Now its temperature is 2.73 K, corresponding to microwaves. In 1964, Penzias and Wilson, two engineers of Bell Telephones, working on communication with a satellite, observes a strange noise. They got Nobel prize for it in 1978.
The light that is reaching us has been stretched out as the universe has stretched, so light that was once visible now is reaching us in the form of microwaves.
COBE in 1990 and WMAP in 2003 showed not only that Universe started
as a ball of wriggly plasma but also that it is flat to the most remote corner.
A microwave map of the whole sky made the Cosmic Background Explorer (COBE) Differential Microwave Radiometer (DMR).
What is the geometry of the Universe?
The density of matter inside the Universe determines its geometry: for a high density we will obtain a closed universe with a positive curvature, but with a density lower than the critical density, we will obtain an open universe.
Time evolution of the Universe for different mass density parameter 0 which measures the ratio between the density of the studied universe and a particular density, called the critical density c. (about 610-27 kg/m3 ).
Closed Universe looks like
the surface of a sphere
Some scientist say that time-space is closed, and folded inside like the Swiss cheese. But recent observations show that it is flat, or better, cubic.
Moreover, the Universe accelerates its expansion and we do not know why!
Open Universe looks
like a horse saddle
Georges Lemaître (1894-1966) from 1935
was a canon of the cathedral in Malinas.
Mikołaj Kopernik (1473-1543) from 1510
was a canon of the cathedral in Frombork.