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- I want to make one clarification on my video on super, or actually I should say supernovae,
- because that's the plural for supernova, is that I said this supernova occurred a thousand years ago.
- That's actually not precisely right.
- The supernova was first observed 1,000 years ago.
- Or the light from that first explosion was observed by astronomers, we believe, 1,000 years ago.
- But we have to be very clear here because the Crab Nebula, and its core is roughly 6,500 light years
- away. Even this light, even this image we see right here is that nebula as it was 65 hundred years ago.
- And so the supernova itself, if you think about when it actually occurred,
- it actually must have occurred about 75 hundred years ago.
- So it must have occurred about 75 hundred years ago, years ago, and that first light,
- from that first explosion from that first energetic event reached us about a thousand years ago.
- So it took 65 hundred years to get to us, and reached us a thousand years ago.
- So first, first light 1,000 years ago, 1,000 years.
- I just wanted to make that clear, it might have been obvious to some of you all,
- but always important to think about it. When I said a thousand years ago,
- I really should have said it was first observed, the explosion was observed a thousand years ago.
- But since it's so far, the actual event must have occurred 75 hundred years ago.
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