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Ignoring the impossibility of the sun suddenly collapsing, and the energy release (which would kill us): If the sun suddenly turned into a black hole, could we survive if we had sufficient energy for heat, light, etc?

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I'm quite confused by your question. Can you explain me your last sentence..? –  Waffle's Crazy Peanut Mar 3 '13 at 14:26
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I'm asking whether us orbiting around a black hole rather than the sun would make it impossible for us to survive, even if we have enough energy from oil and other sources for heating and light? –  DarkLightA Mar 3 '13 at 14:34
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@DarkLightA No, we would be happy to live around a black-hole. I gave an answer. Please refer to it. –  Cheeku Mar 3 '13 at 14:48
    
Re the "sufficient energy" bit: reading this question immediately reminded me of a classic Fritz Leiber short story "A Pail of Air" - en.wikipedia.org/wiki/A_Pail_of_Air - which is concerned with what could happen to the earth if it was ejected from the solar system (removing the warmth of the sun by replacing it with a black hole amounts to the same thing of course). –  timday Mar 25 '13 at 19:13
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2 Answers

up vote 3 down vote accepted

I assume that what you basically mean is that

Suppose there is infinite food and energy for our survival, but if the Sun turns to a Black Hole, will it pose a threat to us?

The answer is NO. We would just be orbiting it as we do now. There is no reason why should there be any effect on gravitational force on Earth from the Sun, since it is dependent on total mass and distance from Sun's center to Earth's center. None of these factors change.

If you're still confused, pay attention to the fact that there is a supermassive(about a million times the Sun) black hole at the center of our Galaxy and the whole Galaxy is orbiting it in a way, nothing really happens to it.

Always remember that black holes are not something which sucks everything around it. If that would have been the case, the universe would be far more empty. They have got a bad impression just because they don't let light escape, not because they suck everything around them.

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Alright, I'll start building my survival pack! Haha, no, but I'm wondering: if an object gets close to a black hole will it actually be sucked in, or will it just get "slingshotted" back out? –  DarkLightA Mar 3 '13 at 14:50
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No, it will be sucked in. I mean a black-hole is harmless if you're at Earth behaving like a good boy to it. But if you get close enough, you'll be ripped apart. The point is this: Although, the gravitational force at any point will remain same, the tidal forces will increase. So, while a normal Sun will just push you in at a particular distance, a black hole Sun will rip you apart. That's why black-holes have a bad reputation. –  Cheeku Mar 3 '13 at 14:56
    
Right. Does this mean it will be more likely to gain mass than the sun? –  DarkLightA Mar 3 '13 at 14:58
    
Ya..it's a black-hole after all. It'll definitely be more likely to gain mass. It "may" even gather an accretion disk, which is in theory supposed to be a beautiful sight from earth. en.wikipedia.org/wiki/Accretion_disc –  Cheeku Mar 3 '13 at 15:00
    
Huh, why though? When the gravity remains constant, won't everything that would hit the black hole also have hit the Sun? –  DarkLightA Mar 3 '13 at 15:03
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I wonder just for few day's till our resource are available for food and heat. But it will not change because it's mass is not sufficient to become a black hole

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What do you mean, pulled and crushed? The gravitational pull would remain constant. –  DarkLightA Mar 3 '13 at 14:24
    
Hi Akash. Your second phrase is quite right. But, your first phrase says few hours & then we'll be pulled. For now, I'll have to say, "Even light takes 8 mins to reach earth".. Why is gravity a late-comer..? –  Waffle's Crazy Peanut Mar 3 '13 at 14:27
    
Oh sorry yes it will remain constan just inserted effect's of a real black hole sorry. But first thing is that it will not turn into a black hole as it's size and mass is not sufficient for that event to take place. Secondly we can survive but not fo rtoo long because all our resources for heat will get depleted soon. –  Akash Mar 3 '13 at 14:31
    
Hmmm if it will turn into a black hole gravity will show it's effect in the time which it normally take but it will take a few hour to reach the earth to the black hole and get torcherd by it's gravity. But as I mentioned i did a little bit mistake in my statement –  Akash Mar 3 '13 at 14:35
    
Does a gravitational acceleration really take time to travel? –  DarkLightA Mar 3 '13 at 14:40
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