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I'm reading this silly Time article: http://www.time.com/time/health/article/0,8599,2044517,00.html

And they say "Even at its best, the 20-year-old telescope never had the acuity to peer so far into space, where the rapid expansion of the universe causes light waves to shift to a deep red."

Doesn't that imply that things in the far universe are expanding more quickly? Is that true?

Isn't space expanding faster than the movement of objects within space? Do both cause redshift to be observed?

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3 Answers 3

this is just an observation of the Hubble's Law which states that the redshift is proportional to the distance of the galaxy. This empirical observation is explained by the isotropic expansion of the universe (that is, a rate of expansion in the metric scale) which implies that observationally, you will see farther objects to speed away faster, since there is more new volume of space per unit of time that separates from those points

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Is it correct to say that they just look like they're moving faster from our viewpoint? –  themirror Feb 16 '11 at 21:18
@marienbad, that is correct. –  lurscher Feb 16 '11 at 21:45

The local Hubble law is the velocity of a galaxy at a distance $d$ moves with a velocity $v~=~Hd$. So the further out you observe the faster things are moving away.

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Actually, the answer is far worse than that.

The universe was expanding more slowly in the past than it is today. Of course, the initial reaction to this discovery was "No, that can't be right. There must be something wrong with the way we're measuring it". But after some oh, 20 years of observations with different equipment and methods, we're coming up with the same result.

Which, to anyone with a basic knowledge of Newtonian physics and an inkling of the mass of the universe, just trying to contemplate the amount of force required to make that happen could make your brain explode. Even astronomy has not before come up with numbers quite astronomical enough to describe the amount of energy required to make this happen. And to top it all off, we have as of yet no way of detecting the nature of this energy, or any of its properties.

It turns out that whatever this energy is, it makes up an astounding 73% of the universe.

Unfortunately for astrophysicists, this utterly insane phenomenon is really real. More information: http://en.wikipedia.org/wiki/Dark_energy

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