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View Full Version : Death from the skies: Falling into a black hole



Loren Pechtel
2009-Mar-22, 04:14 AM
This one is more substantial than the previous one.

Page 134, next to the last paragraph.

It says that when the black hole is 7 million miles away it's gravity is as strong as the Earth's and thus people float. This makes no sense--the Earth would be falling in, not pegged to the sky.

The only force that people on the Earth would be feeling is the tide and that would only apply in a radial direction. I could believe that it's supposed to be a 1g tide at that distance but I don't think there would be anyone around to experience it--I think the squashing of the planet would have already killed everyone with vulcanism by then.

nauthiz
2009-Mar-22, 05:50 AM
It makes some sense. It could be the same kind of effect that gives rise to Roche limits (http://en.wikipedia.org/wiki/Roche_limit).

hhEb09'1
2009-Mar-22, 12:08 PM
This one is more substantial than the previous one.

Page 134, next to the last paragraph.

It says that when the black hole is 7 million miles away it's gravity is as strong as the Earth's and thus people float. This makes no sense--the Earth would be falling in, not pegged to the sky.

The only force that people on the Earth would be feeling is the tide and that would only apply in a radial direction. I could believe that it's supposed to be a 1g tide at that distance but I don't think there would be anyone around to experience it--I think the squashing of the planet would have already killed everyone with vulcanism by then.I think nauthiz is right, but the BA probably did take some liberty with this one. If people were floating, then so would be large buildings, reservoirs, oceans, chunks of mountain ranges... probably a red alert day for people with asthma and other lung conditions.

Loren Pechtel
2009-Mar-22, 03:00 PM
I think nauthiz is right, but the BA probably did take some liberty with this one. If people were floating, then so would be large buildings, reservoirs, oceans, chunks of mountain ranges... probably a red alert day for people with asthma and other lung conditions.

I don't think anyone would be alive to experience it. Long before it reached the zero-g point the differential pressure would have seriously changed the shape of the Earth as the mass attempts to redistribute to an equal-potential surface (Not that any such solution exists, the more it elongates the greater the stretching.) I see no reason to think that would have gone smoothly.

Gillianren
2009-Mar-22, 06:42 PM
I think nauthiz is right, but the BA probably did take some liberty with this one. If people were floating, then so would be large buildings, reservoirs, oceans, chunks of mountain ranges... probably a red alert day for people with asthma and other lung conditions.

Churches, churches, very small rocks?