Expansion rate of the universe

[saywhat]

Most articles sate that basically the further away an object is, the faster it is moving away from us therefore the universe is expanding faster which leads to dark energy to explain the increasing accelaration
But as we see distant objects as they were in the past due to the finite speed of light isn't this also equivalent to saying :
"when we look further back in time, things were accelerating apart faster then they are now" which implies the rate of expansion is slowing?
thanks.

 

[bcrowell]

Most articles sate that basically the further away an object is, the faster it is moving away from us therefore the universe is expanding faster which leads to dark energy to explain the increasing accelaration

You don't quite have this right. The proportionality of recession velocity to distance just shows that the universe is expanding. To show that the expansion is accelerating requires breaking the simple proportionality. You're using "increasing acceleration" to mean "increasing velocity." Velocity increases even if the acceleration is constant.

 

[vikramblue]

the universe had a inflationary period when it expanded very fast.then it slowed down.presently the universe is expanding with increased acceleration.
the expansion rate is about 2 to 20 times speed of light.(not sure)

Adam Riess and his team observed quite a few galaxies in this way, and figured just how fast the Universe is growing to unprecedented accuracy. His result: 74.2 ±3.6 kilometers/second/megaparsec. That means for every megaparsec (about 3 million light years) you go out, the Universe is expanding 74.2 km/sec faster. So a galaxy 10 Mpc away would be moving away from us at 742 km/sec. Adam’s measurement jibes well with other measurements, so there is reason to be confident in his results.

http://blogs.discovermagazine.com/badastronomy/2009/05/07/the-universe-is-expanding-at-742-kmsecmpc/

 

[bcrowell]

the expansion rate is about 2 to 20 times speed of light.(not sure)

The expansion rate can't be measured in units of speed. The speed of one galaxy relative to another depends on distance.

 

[sardar]

Thank you for your question. I can tell you that the expansion rate of the universe is a complex and ongoing topic of research in the field of cosmology. While it is true that the further away an object is, the faster it appears to be moving away from us, this does not necessarily mean that the universe is expanding at a faster rate. In fact, the current consensus among scientists is that the expansion of the universe is accelerating, and this acceleration is being driven by a mysterious force known as dark energy.

To address your point about the finite speed of light, it is important to understand that the light from distant objects takes time to reach us, so we are indeed seeing them as they were in the past. However, this does not mean that the rate of expansion was faster in the past. In fact, the evidence from various observations, such as the cosmic microwave background radiation and the distribution of galaxies, suggests that the rate of expansion has been fairly constant over time.

The concept of dark energy was proposed to explain the observed acceleration of the expansion of the universe. It is still not fully understood, and scientists are actively researching its nature and properties. It is possible that the rate of expansion may change in the future, but at this point, there is no evidence to suggest that it is slowing down.

In summary, while it may seem intuitive to think that the rate of expansion was faster in the past, the current evidence points to a fairly constant expansion rate with an accelerating trend. Further research and observations will continue to shed light on this fascinating topic. Thank you for your interest in cosmology.