Universe AgeSize with respect to DM?

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In summary, the percentage of dark matter in the universe is currently around 23% of the critical density. Its contribution to the flatness of the universe is changing over time, but it has been relatively constant in relation to baryonic matter. The exact amount of dark matter and its composition is still unknown, but it is believed to have been present in some form since the Big Bang. The ratio of dark matter to baryonic matter may have been different in the past, and it is possible that some of the dark matter could be in the form of baryonic matter such as planets. However, the exact nature of dark matter and its role in the universe is still a subject of ongoing research and debate.
  • #1
Spin_Network
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What are the prospects of Aging the Universe with respect to the Dark Matter Content of our perceived Universe?..and can we gauge the size of the Universe with respect to the percentage of Dark Matter?..ie..DM amounts to about 95%,,does this have a baring on the Universe age and size?
 
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  • #2
The total mass in dark matter should not change with time, but its density relative to the critical density will. In other words, its relative contribution to the flatness of the universe changes with time. Before the "lambda transition" where the dark energy became the dominant contribution to the flatness, dark matter's contribution had been increasing with time. Now, we think that its contribution is decreasing.

I'm not sure where your "95%" number came from. The current percentage of the critical density that's dark matter is about 23%.

Oh, and yes, the relative contributions of dark matter and dark energy do make a difference for the size and expansion rate of the universe. The relative contributions of baryonic and dark matter to the total matter budget don't impact the expansion rate or size, however.
 
  • #3
SpaceTiger said:
The total mass in dark matter should not change with time, but its density relative to the critical density will. In other words, its relative contribution to the flatness of the universe changes with time. Before the "lambda transition" where the dark energy became the dominant contribution to the flatness, dark matter's contribution had been increasing with time. Now, we think that its contribution is decreasing.

I'm not sure where your "95%" number came from. The current percentage of the critical density that's dark matter is about 23%.

Oh, and yes, the relative contributions of dark matter and dark energy do make a difference for the size and expansion rate of the universe. The relative contributions of baryonic and dark matter to the total matter budget don't impact the expansion rate or size, however.

I see, can you point me to a source that explains the Big-Bang evolved from a Proton Sized entity..and is this Proton sized 'object', Dark Matter free?

A simpler question is:Was the Dark Matter 'percentage' always the same ratio( 75% *) at the Big-Bang?..and would there be a small 'fraction' still evident within ..say a Proton today?

Thanks for the correction, I was incorrect in my original ratio.
 
  • #4
Spin_Network said:
I see, can you point me to a source that explains the Big-Bang evolved from a Proton Sized entity..and is this Proton sized 'object', Dark Matter free?

I don't think we have a strong enough grasp of physics to confidently extrapolate that far back (if it even goes that far), but whatever the dark matter is, it would be in an entirely different form at that point.


A simpler question is:Was the Dark Matter 'percentage' always the same ratio( 75% *) at the Big-Bang?

The ratio of non-baryonic matter to baryonic matter has been the same for most of the history of the universe. Whether it has always been the same is an issue for particle physicists to address (i.e. whether baryon number is always conserved). Dark matter, however, can include some baryonic matter (like planets). Thus, the ratio of dark matter to luminous matter will change with time.


..and would there be a small 'fraction' still evident within ..say a Proton today?

I'm not sure what you mean by that.
 

Related to Universe AgeSize with respect to DM?

1. How old is the universe?

The current estimated age of the universe is approximately 13.8 billion years. This age is determined through various methods such as measuring the expansion rate of the universe and the cosmic microwave background radiation.

2. What is the size of the universe?

The observable universe, which is the portion of the universe that we can see, has a diameter of about 93 billion light years. However, the actual size of the entire universe is unknown and may be infinite.

3. What is dark matter?

Dark matter is a type of matter that does not emit or interact with light, making it invisible to telescopes and other instruments. It is thought to make up about 27% of the total mass in the universe and plays a crucial role in the formation and evolution of galaxies.

4. How does dark matter affect the age and size of the universe?

Dark matter does not directly affect the age and size of the universe, but it does play a role in the expansion of the universe. Its gravitational pull helps to slow down the expansion, allowing the universe to continue to evolve and grow.

5. How do scientists study dark matter?

Scientists study dark matter through indirect methods such as observing its gravitational effects on visible matter, studying the motion of stars and galaxies, and analyzing the cosmic microwave background radiation. They also conduct experiments with particle accelerators to try and detect dark matter particles.

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