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by **Ragoo** » Wed May 06, 2009 9:57 am

Hello everybody!!!!!
I need your help. Any information about "Universe evolution".
Pressing in need.Thanks a lot!

by **Bug** » Wed May 06, 2009 10:03 am

Universe evolution

We know that, the Universe is a material world examined from the astronomical point of view.
Сosmology is a physical doctrine about the Universe as whole, including the theory of all world captured by astronomical supervision as Universe parts. In the Universe slowly there are the changes having irreversible character, for example its expansion. An observable part of the Universe usually name the Metagalaxy. The metagalaxy is made by various observable structural elements: galaxies, the stars supernew, quasars etc. the Sizes of the Metagalaxy are limited by our possibilities of supervision and now equal 1026 m. are accepted .
Clearly, that the concept of the sizes of the Universe is rather conditional: the real Universe is boundless and does not come to an end anywhere.

Part of heavenly sphere of the small size. Except for several stars all objects in a photo - far galaxies.

by **Ormin van Bung** » Fri May 08, 2009 9:52 am

Come into any search engine and set in search Universe evolution.
:?:

by **Ragoo** » Mon May 11, 2009 2:53 pm

That`s all?

by **Dr.exact** » Mon May 11, 2009 2:55 pm

Universe evolution.

The Universe does not keep all time in the same state - it evolves.
To understand it, it is possible measuring speed of movement of far galaxies. Supervision show, that far galaxies leave from us with a speed u, proportional to distance r to them. The formula u = Нr shows Hubble's well-known law. The factor of proportionality Н is called Hubble's as constant and is approximately equal 50 (km/s)/Mps. We will notice here, that the name "constant" shows in this case only on independence Н of quantity and a vector direction r.

To establish this law, it was necessary to learn to define speed of movement of galaxies and distance on which they are. The principle of definition of speed is that. Radiation of galaxies contains the spectrum lines belonging to certain chemical elements (recollect, for example, “a yellow line” natrium which you see when table salt NaCI gets to a flame of a gas-jet).

by **Dr.exact** » Mon May 11, 2009 2:56 pm

Physics laws everywhere are identical. The length of a wave of a certain line at the moment of radiation is identical on the Earth and in any farthest galaxy. If the source leaves, according to effect Doppler the based observer will accept the radiation displaced by the red end of a spectrum, in other words, length of a wave for the observer will increase.
Effect Doppler will give the chance not only to measure speed of galaxies leaving from us, but "works" and on highways. Car inspectors are armed by the special device - the "pistol" measuring speed of coming nearer or leaving motor vehicles. Unlike space objects, automobile do not radiate, and only reflect the electromagnetic impulse which is let out by "pistol".

by **Dr.exact** » Mon May 11, 2009 2:57 pm

Think, how it have an influence on quantity of Doppler effect?
And how to define distances to galaxies? This problem - one of the most important and the most difficult in cosmology.

Astronomers, studying and classifying objects rather close to us, have found among them such, luminosity and which sizes are at least approximately known. It has allowed to find distances to the similar objects which are far.
Comparing distances with displacement of spectrum lines, astronomers have established Hubble's law and have found constant Н. On the other hand, when Hubble's Н constant is already known, distance measurement can be shown to definition of speed u (or displacement z). Certainly, we do not have any bases to think, that we occupy any allocated position in the Universe. Naturally therefore, that the observer in any other galaxy too will see a picture of the escaping galaxies removed from him. Relative speed of any two galaxies is proportional to distance between them.

This statement follows from Hubble's law (check up!).

by **Lagoon** » Sat Sep 26, 2009 2:34 pm

About 11 to 15 billion years ago all of the matter and energy in the Universe was concentrated into an area the size of an atom. At this moment, matter, energy, space and time did not exist. Then suddenly, the Universe began to expand at an incredible rate and matter, energy, space and time came into being (the Big Bang). As the Universe expanded, matter began to coalesce into gas clouds, and then stars and planets. Our solar system formed about 5 billion years ago when the Universe was about 65% of its present size (Figure 5a-2). Today, the Universe continues to expand.

: Figure 5a-1: Hubble Space Telescope view of a distant cluster of galaxies near the beginning of time. (Source: AURA/STScI).

: Figure 5a-2: Our solar system began forming about 5 billion years ago as gas clouds coalesce into planets and a star. Today, the solar system contains nine commonly recognized planets and the Sun. (Source: NASA).; planets.jpg (22.82 KiB) Viewed 31 times

by **Lagoon** » Sat Sep 26, 2009 2:41 pm

by **Roiglobal** » Thu Oct 15, 2009 4:15 pm

We still do not know how the large scale structures and galaxies were formed.
But we believe during the first million years, the universe was full of photons, much more than the matter.
After a million years or so, matter dominates and the large scale structures and galaxies began to form.
The sum of mass density and the dark energy density determine the future of the universe.
The dark energy density is the energy of the vacuum, which is also called the cosmological constant.
Although we can measure it, we do not know much about it.
There is a value called the critical density.
If the sum is larger than the critical density, then the universe will eventually stop its expansion and start to collapse.
We call it a closed universe.
If it is smaller, the universe will expand forever.
It is an open universe.