Re: Geniuses predict how the world will end, and how to avoid it

According to the infallible Fox TV, the USA has many thousands of 'preppers' (people PREPARING for 'doomsday').

They build all manner of shelters, stockpile food and water, spend heaps on alternate energy, operate elaborate 'ham' radio gear and of course .....

arm themselves to the teeth (they're Yanks) to fend off others who have NOT prepared for the imminent collapse of the world as we know it.

Re: Geniuses predict how the world will end, and how to avoid it

I don't think the survivalists will stand any better chance than the rest of us if one of the possible 'mass extinction events' occurs. A planet killer asteroid impact, one of about 5 miles in diameter would do the job nicely. A relatively near supernova, or a hypernova somewhere in our galaxy would also probably do the job as well. The gamma ray burst associated with these events would destroy a large percentage of the ozone layer with associated radiation effects and cataclysmic disruption to the ecosystem. Then of course, we've got the potential for a 'super volcano', The Yellowstone Park caldera is a possible candidate.

Any of these events has a high probability of happening well before the sun does the job.

Re: Geniuses predict how the world will end, and how to avoid it

It's nice to know some of the genius brains in the world make mistakes like the rest of us mere mortals, pity they find it so hard to admit to them.
Looking at BBC 4 the other night I was pleasantly surprised to hear several well know Astrophysicists say the three words they spend all their lives trying to avoid “I don’t know” The program was called “Who’s afraid of big Black Holes?” or something like that, and as usual it was way above my humble head, I don’t know why I watch these programs in the first place, maybe I’m just mad about anything to do with Space, but I do hate eggheads telling us that they know this and that for sure when so many of them have been proved wrong, they are even having a go at old Einstein’s theories now, well thats a good sign, he wasn’t God after all, anyway it seems when you come to what’s called a “Singularity” at the centre of a black hole you are lost according to all the laws of physics, (maybe at this point Astrophysicists might suspect that there is a God after all) that to me is very refreshing to hear, so what do you do when the laws of physics don't work anymore? Ask God?, no you ask an Astrophysicist, well this person does.
The following question is from “Ask an Astrophysicist” wouldn’t it be easier to answer “I don’t know” the questioner is still no wiser with the answer given is he? Watch out for that key word “Singularity” although I doubt if you’ll hear it very often anymore, I do know that politicians will be avoiding it like the plague, it simply means YOUR STUCK AND YOU DON’T KNOW! Why is that so hard to say?

The Question.
At the center of a black hole the singularity point has zero volume and infinite density. I know that the singularity is a point in space rather than an object with specific dimensions, but how is it possible for something to have zero volume and infinite density? ================================================== ==============

The Answer
This is indeed difficult to grasp. Actually at the center of a black hole spacetime has infinite curvature and matter is crushed to infinite density under the pull of infinite gravity. At a singularity, space and time cease to exist as we know them. The laws of physics as we know them break down at a singularity, so it's not really possible to envision something with infinite density and zero volume. You might check out the web site for further information on black holes and singularities:
http://antwrp.gsfc.nasa.gov/htmltest/rjn_bht.html.
Hope this helps,
Georgia & Koji
For "Ask an Astrophysicist