It's a fascinating concept. What a shame it can't happen in the real world.

On 7 December 2013 07:42, John Clark <> wrote:

> On Thu, Dec 5, 2013 at 8:11 PM, LizR <> wrote:
> > Ah yes I've heard that the gravity at the event horizon can be as weak
>> as you like with a suitably large hole - that you might not even realise
>> you'd crossed it
> Yes.
> > though surely you'd get some optical effects?
> If you were falling back first into a Black Hole things that were behind
> you would start to look as if they were ahead of you, and as you got very
> close to the event horizon all the light from the entire external universe
> would be coming to you from a small disk directly in front of you. When you
> actually crossed the event horizon (the point of no return) the diameter of
> that disk would shrink to zero and you'd be forever cutoff from the
> universe you knew. If the Black Hole were large enough you could still be
> alive when you crossed the event horizon, although a few seconds later
> tidal forces would rip you apart through spaghettification
> > So the Michell star is effectively like a solid version of a black
>> hole's event horizon.
> It's more than that, at the event horizon of one of Einstein's Black
> Holes, even if the gravity was only 1g, you could never escape the Black
> Hole and return to Earth no matter how powerful your rocket is; on the
> surface of Michell's dark star even if it was a billion g you could escape
> if your rocket was powerful enough (assuming a billion g didn't prove
> harmful to your health).
>   John K Clark

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