Accelerating Universe,rate Of Acc Data Needed

In summary, the author is looking for data that would support the theory that the universe is accelerating. He references a paper that explains the correlation between gravitational attraction and the dark energy repulsive force. He states that the net resultant force is negative at time slightly greater than zero, grows to a positive repulsive force, and then decreases to a ever decreasing but always positive repulsive force as the universe becomes bigger.
  • #1
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I am looking for some data for the deceleration/acceleration of the universe over time/distance. I would love to have matching data with the expected deceleration force due to gravity and any other factors presently known to exist, ideally with margin of error.
I am ready to compare it with my predicted calculations...
Thanks
Ed
 
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  • #2
We don't directly measure acceleration or deceleration but have to infer it based on a model, derived from General Relativity, and observations of objects in the Universe. The most 'direct' method we currently have of tracking the expansion history is by observing the magnitude vs redshift of a particular class of Supernovae. By calculating the what the GR model predicts we would observe, we can compare the predictions with observations and work out the parameters of the model. When we do this the result is that the expansion of the Universe must be accelerating.

If you have a different model (I think that's what you are saying?) what you need to do is work out what the predictions of the model are for things that we can observe, such as the Supernovae data, and compare it to the observations. You can't however take the acceleration or deceleration implied by fitting the GR model to the observations and test your model against that. Everything always comes back to what we can actually observe.

If you want to see in more detail how this is done have a look at http://arxiv.org/abs/astro-ph/0510155" [Broken] paper. There are plenty of others out there as well, that is just one example.
 
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  • #3
Wallace, thanks for the link. I did know about the supernova redshift measurements, but not to the details given in the paper.
I am an engineer, not an astrophysist, so I am not familar with all the terminology contained within some of the references I find. In my model the repulsive dark energy force (I dislike this term) is much smaller in a young universe than the attractive gravitational force. With increasing time/distance, the dark repulsive force decreases at a slower rate than the attractive gravitational force. There is a crossing point where the repulsive force is equal to the gravitational attraction after which the accelerating force is greater than the garvitation attraction. Neither force is linear, nor is the resultant net force. As the universe becomes larger the accelerating force will decrease, but never to the point of zero acceleration.

What I have is correlation between gravitational attraction and this dark energy repulsive force relative to distance. A graph of this would look like two decreasing intersecting curves with force on the y-axis and distance on the x axis. The net resultant force would be negative(ie attractive) at time sightly > zero, grow to a posive repulsive force and then decrease to a ever decreasing but always positive repulsive force as the universe becomes bigger.
 

1. What is the accelerating universe?

The accelerating universe refers to the observation that the expansion of the universe is accelerating, meaning that the rate at which galaxies are moving away from each other is increasing over time.

2. How do we know that the universe is accelerating?

Scientists have observed the redshift of light from distant galaxies, which indicates that those galaxies are moving away from us at an increasing rate. This is confirmed by multiple independent measurements, including the cosmic microwave background radiation and Type Ia supernovae.

3. What is the rate of acceleration of the universe?

The rate of acceleration of the universe is measured by the Hubble constant, which represents the current expansion rate of the universe. It is currently estimated to be around 70 km/s per megaparsec, meaning that for every 3.3 million light-years, the universe is expanding by 70 km/s.

4. How is the rate of acceleration affected by dark energy?

Dark energy is the name given to the unknown force or energy that is causing the acceleration of the universe. It is believed to make up about 70% of the total energy in the universe, and its presence is responsible for the increasing rate of expansion.

5. What data is needed to further understand the accelerating universe?

To further understand the accelerating universe, scientists need more precise measurements of the Hubble constant and other cosmological parameters. They also need to continue studying dark energy through various methods, such as observing the growth of large-scale structures in the universe and measuring the effects of dark energy on the cosmic microwave background radiation.

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