# Matter/Energy Ratio: Help Needed on Critical Universe Ques.

• sp3685
In summary, the question asks for the ratio of matter/energy in a proposed critical universe. The possible answers are A) 10/90, B) 50/50, C) 35/65, and D) unknown. The answer is not clear as it depends on the definition of "energy" - if it includes dark energy, then the ratio would be 27:73, and if not, then the answer would be unknown. The consensus is that the universe consists of 23% dark matter, 73% dark energy, and 4% ordinary matter, but as we do not fully understand what dark matter and dark energy are, the most accurate answer would be D) unknown.
sp3685
Hello, I'm new here. This homework question is really stumping me, I can't seem to find the answer anywhere.

In the critical universe now proposed, the ratio of matter/energy is about:
A) 10/90
B) 50/50
C) 35/65
D) unknown

any help on this would be greatly appreciated, thanks!

This is a strange question. What do they mean by "energy"? Do they mean dark energy? If so, C is the closest answer. If they mean radiation energy, then none of the answers are right, so that can't be it. Technically, mass is a form of energy, so I would say that the person who came up with this question needs a physics refresher.

yeah, I originally put C as well, but i realized how confusing this question is and just figured I'd confirm with some of you guys...thanks a lot for your help though...I'll assume it's C but I'll still wait for more replies

Welcome to these Forums sp3685!
Well, it depends on what you are prepared to allow as ‘matter’ and ‘energy’ as SpaceTiger said, he beat me to it!

The general consensus is that the detailed observational verification of this ‘Lambda’CDM model is the mass of the universe consists of 23 per cent dark matter, 73 per cent dark energy and just 4 per cent ordinary matter.

So if dark energy and dark matter are allowed the answer is 27::73 – none of your ‘tick boxes’!
But, as we have no idea what DE and DM are, or even if they really exist, perhaps the answer (D) would be most accurate!

Garth

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## 1. What is the concept of matter/energy ratio?

The matter/energy ratio is a measure of the balance between matter (physical substances) and energy (the capacity to do work) in the universe. It refers to the amount of matter present in relation to the amount of energy that exists.

## 2. Why is the matter/energy ratio important in understanding the universe?

The matter/energy ratio is important because it helps us understand the structure and evolution of the universe. It is a fundamental factor in theories of cosmology and can provide insights into the origin and fate of the universe.

## 3. How is the matter/energy ratio calculated?

The matter/energy ratio is calculated by comparing the amount of visible matter (such as stars and galaxies) to the amount of dark matter (undetected matter that makes up a large portion of the universe) and dark energy (a mysterious force that is thought to be responsible for the universe's expansion).

## 4. What is the current estimate of the matter/energy ratio in the universe?

According to current estimates, the matter/energy ratio in the universe is approximately 5:1, meaning there is about five times more dark matter and dark energy than visible matter.

## 5. How does the matter/energy ratio affect the fate of the universe?

The matter/energy ratio plays a crucial role in determining the fate of the universe. If the ratio is high enough, the universe will continue to expand forever, whereas if the ratio is too low, the universe may eventually collapse in a "Big Crunch". Current observations suggest that the ratio is just right for the universe to continue expanding at a steady rate.

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