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I have recently read some hard science-fiction story based on an assumption that if time stops (from external observer's perspective) on the event horizon of black hole, then in an anti-matter black hole's horizon the time would pass infinitely fast (same perspective)

I thought it was impossible, but I'm not sure anymore.

What would be the effect of approaching the event horizon of an anti-matter black hole?

Is it possible that an infinity of time passes in a finite time (from our point of view) ?

Fun follow-up: if so, can a result of infinite computation be returned to our timeline?

naugtur
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  • More on "anti-matter black holes": http://physics.stackexchange.com/q/25982/2451 and http://physics.stackexchange.com/q/5615/2451 – Qmechanic Oct 12 '12 at 23:11

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A black hole may result from a gravitational collapse of either matter or antimatter, but the black hole itself is a geometrical object — a feature of the shape of space-time, not a material object. The behaviour of space-time at or near to a black hole is the same however it originates, so long as the bulk is electrically neutral; and a charged black behaves the same regardless of whether its charge is due to having absorbed e.g. more protons or more positrons.

Therefore, there is no real distinction between a "matter" black hole and an "antimatter" black hole; in particular, a black hole which happened to form due to the gravitational collapse of a large amount of antimatter would be indistinguishable from a black hole arising from a collapse of matter (or indeed from a sufficiently dense combination of matter and antimatter, arising from a dense nugget of matter and a dense nugget of antimatter brought together that only achieve the "critical density" as they approach each other).

Niel de Beaudrap
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  • "The behaviour of space-time at or near to a black hole is the same however it originates." This is false. For example, a black hole with electrical charge differs from an electrically neutral black hole. –  Oct 13 '12 at 01:22
  • Thanks for clearing this for me Niel. @BenCrowell Could You elaborate (or better - give a link)? – naugtur Oct 13 '12 at 08:33
  • @BenCrowell: right, a bit too hastily written. Edited. – Niel de Beaudrap Oct 13 '12 at 09:39
  • @naugtur: http://en.wikipedia.org/wiki/No-hair_theorem –  Oct 14 '12 at 18:54