Hubbles vs. Dark Energy: Debunking the Mystery of Galaxy Expansion"

In summary, the further away a galaxy is, the faster it is moving. But according to dark energy, the rate of expansion is increasing, meaning the closer, younger galaxies would be traveling faster than the farther, older ones. So it's unclear which picture is correct - Hubble's or dark energy's.
  • #1
discord73
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0
So Hubbles observations showed that the further away a galaxy is the faster it is moving meaning that older galaxies are moving away faster from us than younger, closer ones. But dark energy says that the rate of expansion is increasing,meaning the closer, younger galaxies would be traveling faster than the farther, older ones. So. Which one is correct?
 
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  • #2
The dark energy picture is more correct than hubble's simple linear expansion picture. Hubble simply didn't have the quality of data to detect the accelerating expansion, and indeed it's not until the late 90's that we finally did. I wouldn't really say Hubble was wrong though -- the situation is rather analogous to Newtonian and Einsteinian mechanics. Newton wasn't really wrong, the domain of applicability of his theory was just smaller than Einstein's.
 
  • #3
So does that mean as we look farther away from our galaxy the expansion speeds up to a certain point of time/distance the expansion starts slowing down as we look further back? Meaning Hubble was right with his data, he could see the universe expansion increasing as he looked further out, he just couldn't see far enough to see where the universe started slowing down?
 
  • #4
So Hubbles observations showed that the further away a galaxy is the faster it is moving meaning that older galaxies are moving away faster from us than younger, closer ones.
No.
1. At any given (cosmological) time, the so-called recession speed of a galaxy is exactly proportional to its distance. The proportionality factor is called H.
2. H is changing with time, getting less and less. "Accelerated expansion" means that H decrases slower than it would if all galaxies were freely floating.
3. Combine this with light travel time to get a recession speed - distance at emission chart. These are more complicated. Look athttp://www.astro.ucla.edu/~wright/cosmo_01.htm" .
 
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  • #5
Ich said:
2. H is changing with time, getting less and less. "Accelerated expansion" means that H decreases slower than it would if all galaxies were freely floating.

Okay so Hubble's Constant isn't constant then? How did Hubble miss that? is the change in H as the farther you go away so slight that he was unable to look far enough away to see a change in H?
 
  • #6
Okay so Hubble's Constant isn't constant then? How did Hubble miss that? is the change in H as the farther you go away so slight that he was unable to look far enough away to see a change in H?
You know, I gave you the link for a reason. Have a look at Hubble's data and decide for yourself.
Hint:1 Mpc~3Mly. Age of the universe ~13700 My.
 

Related to Hubbles vs. Dark Energy: Debunking the Mystery of Galaxy Expansion"

1. What is the Hubble constant and how does it relate to dark energy?

The Hubble constant is a measure of the rate at which the universe is expanding. It is named after astronomer Edwin Hubble, who first discovered this phenomenon. Dark energy is a theoretical form of energy that is thought to be responsible for the accelerated expansion of the universe. The Hubble constant is used to calculate the amount of dark energy present in the universe.

2. How was dark energy discovered?

Dark energy was first proposed in the late 1990s as an explanation for the observed accelerated expansion of the universe. This discovery was made by studying the light from distant supernovae and measuring their redshift. The results showed that the expansion of the universe is actually accelerating, rather than slowing down as previously thought. This led to the theory of dark energy as the driving force behind this acceleration.

3. What is the difference between Hubbles and dark energy?

Hubbles and dark energy are two separate concepts that are related to the expansion of the universe. Hubbles refers to the rate of expansion, while dark energy is a theoretical form of energy that is thought to be responsible for this expansion. In other words, Hubbles is a measurement while dark energy is a theoretical explanation for the measurement.

4. Is there any evidence for dark energy?

While dark energy is still a theoretical concept, there is strong evidence to support its existence. Studies of the cosmic microwave background radiation, as well as observations of the large-scale structure of the universe, have provided evidence for the existence of dark energy. Additionally, the measurements of the Hubble constant have also confirmed the need for dark energy to explain the accelerated expansion of the universe.

5. How does the understanding of dark energy impact our understanding of the universe?

The discovery and ongoing research on dark energy have greatly impacted our understanding of the universe. It has led to new theories and models about the structure and evolution of the universe, and has opened up new avenues for exploration and discovery. Understanding dark energy also has implications for the fate of the universe and how it will continue to expand in the future.

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