A Cosmological Cosmos
This is more what I expected from the Cosmos series – cosmology and some astrophysics, e.g., black holes with the mass of 4,000,000 suns and what it might be like to approach the event horizon of one.
While I appreciated the point they were making, I don’t know how helpful it is to say that the, “Sun’s image is an unreal ghost because the light we see from it is 8 minutes behind and by the time we “see” it the Sun is no longer in that relative position off the horizon.
The same could be said about any image we see – what we see is a ghost of what we were looking at because the light isn't instantaneous. The only difference is that close objects like we see on earth might as well be instantaneous because that light and the object producing the image are essentially in sync for almost all intents and purposes. The moon is about 1 light-second away. So, where do we draw the line? However, I suppose if you ever thought of visiting some distant star or galaxy, even if you could get there instantly, better guess again, because it wouldn’t still be in that location or may not still exist at all. We could say that we’ll cross that bridge when we get to it.
But, I understand that GPS triangulation works by taking advantage of this phenomenon.
I noted Tyson said we couldn't see any objects further away than the light from the crab nebula 6,500 light years away if the earth was only 6,500 years old. Good point.
It’s interesting how they said that they don’t know what happened before the Big Bang but they do have some “crazy ideas” about that. That might have been a phrase I would have used, especially since I'm not an astrophysicist and tend to think the gap between what we can know about that and what science can answer is perhaps getting wider rather than being filled by science. But, I'm surprised to here Tyson put it that way. Thoughts?
Last edited Sunday, March 30, 2014