Is energy conserved in the expanding universe?

In summary, Stephan Hawking's "Into the Universe" may be seen as a way to make science more accessible rather than to educate. In the episode about the existence of God, Hawking states that space is a negative energy that equals the energy of the universe. It is unclear whether this is a literal statement or an analogy. If space is negative energy, and with the concept of inflationary cosmology, energy should continue to be created as the universe expands, resulting in a never-ending cycle of galaxies and matter. It is also worth noting that the ratios of energy in the universe (4% matter, 25% dark matter, 71% dark energy) may not have remained the same since the beginning of the universe.
  • #1
ilikescience94
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I watched Stephan Hawking's into the universe, I know it's more of a way to make science mainstream than to educate people, but in the episode about is there a god, he said that space was a negative energy and that it equaled the same amount as the energy of the universe. I haven't looked into the math or validity of this statement, because I figured I'd take Hawking's word for it. Perhaps I'm misunderstanding the concept, or Hawking used the statement as more of an analogy so that the viewers of the show could understand the concept. If that's the case then let me know, but if space is negative energy, and adds up to the energy of the universe, then because of inflationary cosmology, shouldn't energy continue to be created as the universe expands, resulting in a continuation of galaxies and matter, so that the universe never really dies, or is all the space from cosmological inflation being converted solely into dark energy? Also on a side note, have the percentages of energy in the universe (4% matter, 25% dark matter, 71% dark energy) remained in the same ratios since the universes inception, or have they changed over the years.
Thanks
 
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  • #2
It seems that you assume that energy is conserved. Energy is NOT conserved in the General Relativity (only in some particular cases). Our expanding universe is not one of these cases.

The more accurate statement would be that "energy of the whole universe" can't be correctly defined, rather that it is not "conserved". The last statement is valid for the both WHOLE universe and VISIBLE universe (these 2 concepts are incorrectly mixed in popular TV in more than 50% of cases)
 

Related to Is energy conserved in the expanding universe?

1. What is negative energy in the context of space?

Negative energy is a theoretical concept in physics that refers to energy that has a negative value. In the context of space, it is often used to explain the acceleration of the expansion of the universe.

2. How is negative energy related to dark energy?

Dark energy is a type of energy that is thought to make up about 68% of the universe and is responsible for the acceleration of the expansion of the universe. Some theories suggest that dark energy could be negative energy, but this has not been proven.

3. Can negative energy be harnessed for practical use?

At this time, there is no known way to harness or use negative energy for practical purposes. It is a theoretical concept that is still being studied and understood by scientists.

4. How does negative energy affect the fabric of space-time?

Negative energy is thought to have the ability to warp and distort the fabric of space-time, causing it to expand at an accelerated rate. This is one of the proposed explanations for the expansion of the universe.

5. Is there a difference between negative energy and anti-energy?

Negative energy and anti-energy are not the same thing. Negative energy refers to energy that has a negative value, while anti-energy (also known as antimatter) is made up of particles with properties opposite to regular matter. They are two separate concepts that are not interchangeable.

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