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<blockquote data-quote="freyar" data-source="post: 7548489" data-attributes="member: 40227">Yeah, black holes are weird like this. So you're talking about a time dilation/redshifting effect.&nbsp; If we're far away from where stuff is collapsing, as the stuff collapses just small enough to form the black hole horizon, time near the black hole slows down enough that it looks to us that the black hole actually takes an infinite amount of time to form.&nbsp; But the light gets more and more redshifted. So what we see is the stuff collapsing but never quite getting inside a black hole but still getting dimmer and dimmer. Anything else that falls in later does the same sort of thing, catching up to the originally collapsed matter.&nbsp; On the other hand, according to general relativity, anything falling in doesn't even notice it's passing a horizon (other than tidal forces) but then is suddenly inside a black hole. (There are some theories about quantum gravity that suggest passing into a black hole could be more violent, at least some of the time. This is related to Hawking radiation.)Regarding the larger inside business, how large something looks from the outside is usually something we figure based on surface area.&nbsp; From the inside, we're measuring the volume, and we're used to a particular relation between area and volume, roughly volume proportional to area to the 3/2 power. This is commonly violated in relativity, though we do need to be a little careful about how we measure/define area and volume.&nbsp; But, for a black hole, there is a sensible definition where the surface area is constant but the interior volume actually continues to grow for a long time.</blockquote>

[QUOTE="freyar, post: 7548489, member: 40227"] Yeah, black holes are weird like this. So you're talking about a time dilation/redshifting effect. If we're far away from where stuff is collapsing, as the stuff collapses just small enough to form the black hole horizon, time near the black hole slows down enough that it looks to us that the black hole actually takes an infinite amount of time to form. But the light gets more and more redshifted. So what we see is the stuff collapsing but never quite getting inside a black hole but still getting dimmer and dimmer. Anything else that falls in later does the same sort of thing, catching up to the originally collapsed matter. On the other hand, according to general relativity, anything falling in doesn't even notice it's passing a horizon (other than tidal forces) but then is suddenly inside a black hole. (There are some theories about quantum gravity that suggest passing into a black hole could be more violent, at least some of the time. This is related to Hawking radiation.) Regarding the larger inside business, how large something looks from the outside is usually something we figure based on surface area. From the inside, we're measuring the volume, and we're used to a particular relation between area and volume, roughly volume proportional to area to the 3/2 power. This is commonly violated in relativity, though we do need to be a little careful about how we measure/define area and volume. But, for a black hole, there is a sensible definition where the surface area is constant but the interior volume actually continues to grow for a long time. [/QUOTE]

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