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 Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...The Space and Astronomy Agora Re: Hypothetical Gravity Questions Forum List | Follow Ups | Post Message | Back to Thread TopicsPosted by Bruce J. on April 17, 1997 10:40:20 UTC

: : : : Hello! I was wondering how much gravity our bodies can withstand before the effects of gravity become intolerable. The reason I ask is that it's obvious to me that the state of your body would start to deteriorate long before you even reached the event horizon of a black hole. Given that the farther you are from an object, the less the attraction there is between you and the object, what would be the safest minimum distance you could be to a black hole's event horizon without endangering your health?: : Well, the question you've posted is a little ambiguous. I assume by distance you mean standing distance(not flying away or racing toward).: : Any fighter pilot will tell you that nine G's and you lose conciousness(blackout) negative 3 G's and the same thing happens(red out): : On the other hand you might be fine with one Gee of acceleration jumping off of a twenty story building...until you hit the ground.: : Now, in terms of the sheering force of gravity as you approach the event horizon of a black hole, its reasonable to say that I have no earthly clue at what distance the effects would be detrimental, but I'm anxious to find out.: : Here's an idea. You build a scenario of some detail and I'll see if I can pick a few brains with nothing better to do.: : Here's some more ideas. Consider a person in orbit around the earth; they are essentially weightless, because the centripetal: : acceleration away from earth as they orbit is exactly balanced by the gravitational force toward the planet. Now, picture the: : same thing around a black hole. If you can accelerate yourself (slowly!) to a high enough speed to remain in a stable orbit around a black hole,: : you would experience zero gravity and therefore no physical or mental distortion. depending on your distance from the singularity;: : however, your speed might be so high that you would experience relativistic effects (although you might not notice them), and if you get too close to the: : event horizon, you might not be able to correct for small changes and get sucked in!Is it just very fast acceleration which is disorienting to the human body? Can our bodies otherwise handle travel near the speed of light if our acceleration is slow enough?

: Yes, in theory. If you had a magnificent spacecraft that could accelerate you to 99.9 percent of the speed of light, it would feel just fine to you, just as hovering near a black hole would feel OK. When you got back, your friends might be dead due to time dilation on your part, but you'd be OK and no worse for the wear. The problem with black holes is, theoretically, over very small distances the variation in gravity (acceleration and therefore force) would be so great that your feet would be pulled away from your head to the breaking point (this is true not only of living things but sofas and the Eiffel Tower as well). At the event horizon, which is the main location from which we detect all the intense X-Radiation associated with BHs, matter is strung out so quickly and heated so hot that you would become plasma or some other equally hot and dissociated mess.