Is the Expansion Rate Truly Accelerating?

In summary, the conversation discusses the concept of the accelerating expansion rate of the universe. It is noted that the farther objects are from us, the faster they are moving away from us due to expansion. However, the conversation questions whether this acceleration is due to the rate of expansion itself increasing. It is also discussed how this may affect the time it takes for objects to move to greater distances in the future.
  • #1
thetexan
269
13
I'm studying about accelerating expansion rate.

I am reading that the rate of expansion is accelerating. Now the farther objects are from us the faster they are moving away from us due to expansion. Farther and farther, faster and faster. But that would occur even if the expansion rate is steady. Are they saying that the rate of the expansion itself it accelerating? And won't that mean that the time it takes for an object to move from say 10 billion light years to 11 billion light years from us will be longer now that say a billion years from now?

tex
 
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  • #2
"the rate of expansion is accelerating" is not comparing different distances, it is comparing different times for the same object. If we consider an object where the distance increases by c/2 today, its distance will increase slightly faster tomorrow.
thetexan said:
And won't that mean that the time it takes for an object to move from say 10 billion light years to 11 billion light years from us will be longer now that say a billion years from now?
That is yet another comparison, because there we would track different objects.
 

FAQ: Is the Expansion Rate Truly Accelerating?

What is the expansion rate of the universe?

The expansion rate of the universe is a measure of how fast the universe is expanding. It is typically measured in units of kilometers per second per megaparsec. Currently, the expansion rate is estimated to be around 70 kilometers per second per megaparsec.

How is the expansion rate of the universe calculated?

The expansion rate of the universe is calculated by measuring the distance and velocity of celestial objects, such as galaxies, and using this information to determine the rate at which the universe is expanding. This is done using various observational methods, such as redshift measurements of light from distant objects.

What factors affect the expansion rate of the universe?

The expansion rate of the universe is affected by a variety of factors, including the amount and distribution of matter and energy in the universe, the presence of dark matter and dark energy, and the curvature of space-time. These factors can influence the rate of expansion over different time scales.

Has the expansion rate of the universe always been the same?

No, the expansion rate of the universe has not always been the same. According to current theories, the expansion rate of the universe has changed over time, with the universe expanding more rapidly in its early stages and then gradually slowing down. However, recent observations suggest that the expansion rate may currently be increasing again due to the effects of dark energy.

What is the significance of the expansion rate of the universe?

The expansion rate of the universe is a crucial parameter in understanding the evolution and fate of the universe. It can provide insights into the composition and dynamics of the universe, and help us understand the processes that have shaped the universe since its birth. It also plays a role in various cosmological models and theories, such as the Big Bang theory and the concept of cosmic inflation.

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