Freefall into a Black hole
Recovered historical discussion from Freefall into a Black hole.
Lets take a universe that just exists of our sun, earth and a black hole ( assume stability or whatever ) and some random standard candles so that we can measure distances.
As the sun and earth freefall into the black hole ... what is the visible universe for an observer on the earth? What is event horizon?
I have some pre-conceived idea of the answers but want to hear the opinions of the board.
Archived source: https://web.archive.org/web/20101204091005/http://www.spacetimeandtheuniverse.com/general-physics/4633-freefall-into-black-hole.html
Replies
Wayne Bruinekool
Is this a trick question?
What is "freefall"?
If there is only the sun,earth and hole, you would not see a dust cloud or nebula.
Without space dust or anything to interact with the hole you would not see an event horizon.
If however we allow space dust, given enough dust and normal relativistic motion through space-time, you would see the Milky Way.
Without it the earth and sun would orbit the hole unencumbered by interfering gravities until the orbit decayed, which would, to an observer on earth, appear to take forever or, at the very least, longer then his lifespan.
Tom
Well the point of isolating the system was intended to be part of the question. For the local freefaller he has his own personal event horizon.