no end? no beginning?
2007-01-18 07:59:44 · 5 answers · asked by doorseeker 1 in Science & Mathematics ➔ Astronomy & Space
The key to answering your question is the word "perceive". Perception is dependent upon both the sense being used (with or without instruments) and the human mind of the person gathering data.
The usual sense is sight which is dependent upon electromagnetic radiation. Even with powerful instruments (including radio telescopes) perception of the Universe seems to end the same distance from the perceiver in all directions.
When this information is transmitted to the mind, the mind assumes that the data is consistent with a spherical Universe. Thus the Universe is perceived as a sphere. In reality, it could be the shape of a banana or a donut or even a perfect cube.
2007-01-26 05:37:13 · answer #1 · answered by Richard 7 · 13⤊ 0⤋
Because our knowledge of the universe is based on light. Light travels at (approximately) 300,000 km/sec in a vacuum, (slower in any other medium), and in all directions the rest of the universe is receding from itself (so to speak) at a velocity that depends on distance (look up the Hubble Constant). Now, because light behaves (partly) as a wave, this increasing velocity lengthens the wavelength (and decreases the energy) of starlight and eventually, at a long distance away, the light reaching us has a wavelength too long and of too low energy to be perceived with any method. And that is the distance limit to which we can learn anything about the universe. Because that distance is assumed to be the same in all directions the universe, as far as we can ever tell, IS spherical.
2007-01-18 16:33:52 · answer #2 · answered by David A 5 · 0⤊ 0⤋
Just because planets and stars are so distant of us. It is impossible for us to determine but their directions, never their distances, so there are all of them in a simmetrical disposition. An the simmetrical and regular distribution appears to us as a spherical structure.
It has nothing to do with the limits of the universe, just with the huge distances.
2007-01-18 16:09:35 · answer #3 · answered by Jano 5 · 0⤊ 0⤋
Maybe check out string theory. Also, Scientists think there have been multiple expansions, and collapses, according to Quantum theories. So this expansion that we live in did have a beginning, but time existed prior to that in the last collapse.
2007-01-24 22:50:04 · answer #4 · answered by au197_0 3 · 0⤊ 0⤋
It expanded out from a point therefore one must assume that the expansion was radial.
2007-01-18 18:14:38 · answer #5 · answered by Billy Butthead 7 · 0⤊ 0⤋