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Spaced Out Cosmonaut
Space can expand faster then the speed of light. The Universe was expanding much faster in in the beginning. We can only see 13.7 billion light years away, that's where space starts to expand faster then the speed of light and this expansion is increasing the further you go. So you can imagine the space expansion speed at the edge of our observable universe, is just a tiny number compared to other parts of the unobservable universe, which to our comprehension is basically infinite. Space can basically expands infinity faster then the speed of light.
Cattivikkio
This is a very pertinent question and I would guess your confusion arises from the fact that you assume space cannot expand faster than light. If that was the case, yes, it would take at least one year for the universe to be two light years across.
However, as Spaced Out Cosmonaut correctly pointed out, space (as a metric) can expand much faster than light. In particular, during the Inflactionary Epoch, it expanded at a speed of about 40 orders of magnitude greater than the speed of light
However, as Spaced Out Cosmonaut correctly pointed out, space (as a metric) can expand much faster than light. In particular, during the Inflactionary Epoch, it expanded at a speed of about 40 orders of magnitude greater than the speed of light
Ana
A light-year is a measure of distance, not time; it refers to the distance light can travel through a year (9.4607 × 10^12 km or nearly 6 x 10^12 miles).
When Neil says the universe is two light-year across, it's a reference to its "size" at a certain point in time (and then he continues to write about another point in time, two minutes later).
When Neil says the universe is two light-year across, it's a reference to its "size" at a certain point in time (and then he continues to write about another point in time, two minutes later).
Eryn
They were talking about 2 minutes into the start of the universe. Like, in the beginning there was nothing, 2 minutes (later with all the stuff they were explaining was happening) it was a few light years wide. A light year is measured in the time it takes for light from the sun to reach earth in a year I believer. Something like 10 trillion km. So at 2 minutes old, the universe was trillions of km wide, but continued to expand.
Forked Radish
You're 100% right, it's a paradox. Einstein, like everyone who actually understands relativity, would call b----t on the expansion hypothesis.
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