What is the proof that it is true and meaning of EXPANSION THEORY?
2007-02-20 23:15:04 · 8 answers · asked by girly_sexy 1 in Science & Mathematics ➔ Astronomy & Space
The proof is they are still tracking the expansion and have located the 'echoes' from the big bang - the galaxies are still moving apart hence the universe is still expanding!
2007-02-20 23:20:33 · answer #1 · answered by jamand 7 · 0⤊ 0⤋
Expansion means the universe is getting bigger (expanding). Simplest way is to take a picture of the night sky, wait 40 years, take a new picture and see if the stars have moved relative to each other. This has been done (OK, nowadays you can do this instantaneously, but you get the picture - see Tenebra's answer (above)) and yes, the universe is expanding. The expansion is due to energy from the beginning of time (Big Bang). The theory goes that due to the gravitational pull of mass at the centre of the universe, this expansion will slow down. (At one point people wondered if the expansion would stop, and that the stars would start heading towards the centre of the universe again) Currently it is thought that the universe will expand eternally.
2007-02-20 23:33:14 · answer #2 · answered by mustafa 2 · 0⤊ 0⤋
1. Expansion is not a theory. It is an observation. Theories (such as the Big Bang theory and the Steady State theory) were created in order to explain the behaviour of an expanding universe. 2. The expansion rate is very SLOW over short distances. It is barely 70 km/s over a distance of one million parsecs (= 3.26 MILLION light-years). This is nothing against the gravitational attraction between two galaxies with masses of billions of "suns". Andromeda galaxy and our Galaxy belong to a Local Group, where gravity keeps them in orbit around a barycentre. Unlike a planetary system (where there is a central object making up over 90% of the mass of the system), the Local Group is made up of three spiral galaxies and a few dozen dwarf galaxies. There is no clear centre object, so that the "orbits" are weird spirals. They are not neat concentric circles (or ellipses) like in a planetary system. The spiral "orbits" cross each other all the time, and when two galaxies try to get to the crossing point at the same time...
2016-03-29 05:28:13 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The main proof is the fact that remote galaxies are moving away from us. This fact has been obtained by examining the light of those very distant objects.
This because of natural phenomenon called the Doppler effect. Remember that light is electromagnetic radiation, and is a wave. Now, when an object that emits radiation moves away, its radiations' wavelength becomes longer the further away it goes; when it approaches, the same wavelength becomes smaller. The longer wavelength of visible light is red, so when a galaxy's light shows a shift towards the red end of the spectrum, we know that it moves away. this is the so-called redshift.
If on the other hand, it moved closer, then it would exhibit a blueshift; blue is the smallest wavelength.
2007-02-20 23:30:49 · answer #4 · answered by Tenebra98 3 · 1⤊ 0⤋
There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.
You Brits should well aware of this by now!
Bruce from Canada
2007-02-24 11:40:53 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Expansion theory is simple. If you are a girl you will understand the theory very fast. ( even males do understand)
Ofcourse it is true
2007-02-20 23:32:17 · answer #6 · answered by suma 3 · 0⤊ 0⤋
Speculation, my guess is the `Red shift`. The universe is expanding.
2007-02-21 15:48:36 · answer #7 · answered by CLIVE C 3 · 0⤊ 0⤋
the galaxies are still moving apart hence the universe is still expanding!
2007-02-20 23:21:32 · answer #8 · answered by PRASSANA K 3 · 0⤊ 0⤋