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?
Best Answer
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).