Eli5: How come the universe is always expanding?
In: 1
The simple answer is dark energy, the weird answer is that we don’t know what dark energy is, its just the explanation for the energy needed for expansion.
eg.
“The universe is expanding because dark energy”
“what’s dark energy?”
“I have no idea”
“so how do you know theres dark energy?”
“because the universe is expanding”
It’s not always expanding, it’s currently expanding. Much like if you timeline an explosion, the time closer to the boom things flew apart in an accelerating way
It used to be point like, an infinitely dense point of energy. Then it expanded. We have absolutely no clue why or how, only that it is expanding today. There is leftover radiation called the Cosmic microwave background that is sort of a baby picture of the young universe we can observe that confirms the idea it’s expanding. Even more interesting is it’s expanding faster due to “dark energy”, a placeholder name for a phenomena we have no clue about.
The answer to your question is also the answer to “what made/started the universe?”
The simple answer is dark energy, the weird answer is that we don’t know what dark energy is, its just the explanation for the energy needed for expansion.
eg.
“The universe is expanding because dark energy”
“what’s dark energy?”
“I have no idea”
“so how do you know theres dark energy?”
“because the universe is expanding”
It’s not always expanding, it’s currently expanding. Much like if you timeline an explosion, the time closer to the boom things flew apart in an accelerating way
The simple answer is dark energy, the weird answer is that we don’t know what dark energy is, its just the explanation for the energy needed for expansion.
eg.
“The universe is expanding because dark energy”
“what’s dark energy?”
“I have no idea”
“so how do you know theres dark energy?”
“because the universe is expanding”
It’s not always expanding, it’s currently expanding. Much like if you timeline an explosion, the time closer to the boom things flew apart in an accelerating way
It used to be point like, an infinitely dense point of energy. Then it expanded. We have absolutely no clue why or how, only that it is expanding today. There is leftover radiation called the Cosmic microwave background that is sort of a baby picture of the young universe we can observe that confirms the idea it’s expanding. Even more interesting is it’s expanding faster due to “dark energy”, a placeholder name for a phenomena we have no clue about.
The answer to your question is also the answer to “what made/started the universe?”
It used to be point like, an infinitely dense point of energy. Then it expanded. We have absolutely no clue why or how, only that it is expanding today. There is leftover radiation called the Cosmic microwave background that is sort of a baby picture of the young universe we can observe that confirms the idea it’s expanding. Even more interesting is it’s expanding faster due to “dark energy”, a placeholder name for a phenomena we have no clue about.
The answer to your question is also the answer to “what made/started the universe?”
We do not know. Answering that question would be a huge breakthrough in science.
We do know that since the Big Bang the universe has been expanding, though not always at the same rate. The initial expansion was incredibly rapid and lasted less than 375,000 years before expansion slowed down a lot. Then about 5-6 billion years ago expansion started accelerating again.
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