Black Holes and White Rabbits

[Cloudwatcher]

The smaller the event horizon, the more pronounced the effect, so black holes evaporate in an accelerated way, leading to a rapid explosion towards the end.

Well, that has made me feel a lot better... instead of getting swallowed into a mini-blackhole's event horizon, we are likely to be caught in the explosion of high energy particles and matter instead. I`ll sleep a lot better tonight

Me too! Unless clear skies are on the even horizon in which case I hope to get very little sleep!

[Phil73805]

But back to the imminent end of the world, when will this new particle accelerator be up and running? is it worth me booking up the holidays for next year?

November 26th 2007, you have been warned

Phil

[iantobach]

BTW Ron meant to say in last post that i bet Prof J Brown's Paul Daniel act hasn't changed a bit- would love to see magic coupled with other scientific teaching.

Imagine if Doctors taught young medical students with the aid of a large saw, box, glamorous assistant and 12 white doves. I would consider a go at medicine if i thought David Blaine was teaching first year!

Have tried teaching my med students in this way.Been pulling the most amazing things out of odd places for years now. :ky: :ky: :tongue9:

[Cloudwatcher]

BTW Ron meant to say in last post that i bet Prof J Brown's Paul Daniel act hasn't changed a bit- would love to see magic coupled with other scientific teaching.

Imagine if Doctors taught young medical students with the aid of a large saw, box, glamorous assistant and 12 white doves. I would consider a go at medicine if i thought David Blaine was teaching first year!

Have tried teaching my med students in this way.Been pulling the most amazing things out of odd places for years now. :ky: :ky: :tongue9:

Ooh err! Hope it's not as painful as it sounds......Still I'm sure your glamorous assistant is a great comfort!

[Astroman]

There are many excellent points in this thread, but just to sum up;

Black holes do not "suck" matter into them. It our Sun turned into a BH right this second, we would continue to orbit in the same fashion we have since the beginning. We'd all be dead in a matter of weeks due to the loss of heat and energy we get from the Sun, but our orbit would remain unchanged for eons untill the BH evaporated. This would happen on a time scale something like the current age of the universe.

It will be possible, theoretically, to create BH's inside the LHC, but the mass of these holes will be approximately the mass of a proton or two, at most. Themos' explanation is as clear as I've seen. The event horizon of a two proton mass BH will be measured in angstroms or smaller, and would evaporate in milliseconds or faster. The mass would return to energy in this time and be detected by the machine, as designed. This is exactly what they have in mind when they build these machines-create, detect and measure subatomic interactions and annihilations and analyze them. The LHC is more than capable of containing such events. That's the whole idea.

Einstein's Cross is an effect of gravity, but not caused by a single BH. It is the entire mass of a galaxy cluster, thousands of galaxies in a clump, that bends the images of much more distant galaxies.

A "Grand Unifying Theory" will not directly result from experiments at LHC, but it will enhance our understanding of subatomic interactions, which may in turn show if we were on the right path before, or force us to make a change of direction. I think there may be a GUT, but we're far from realizing one. We have insufficient knowledge of the very small and the very large structures and their dynamics. The LHC is working on the very small and others on the very large, so it's "in the works", so to speak.

Iantoback made me laugh out loud with his KY smilies and, um, erm expression. I'd better refrain from comments regarding glamorous assistants and the KY. :shock:

Hope this helps. Nice work, guys! Guess you didn't miss me much, even though I missed this thread before I left.

[gurney]

Einstein's Cross is an effect of gravity, but not caused by a single BH. It is the entire mass of a galaxy cluster, thousands of galaxies in a clump, that bends the images of much more distant galaxies.

Sorry for being a pedant! ... but isn't Einstein's cross caused by a single galaxy rather than thousands of galaxies? I'm not sure lensing would work with thousands of galaxies, since they'd be far too huge, and lensing only works on direct line of sight with an interveening object of high mass and density.

But again - I could happily be wrong, and usually am!

[Ajohn]

If you want to try some simple idea's about black holes and their effects there's a science fiction writer called larry niven - all pure fiction but he does research his subjects.

Have to agree about 1 massive galaxy and Einstein's cross.

Me I'm a doubting thomas. Started when I was 8 or 9 and I loaned an astronomy book from the library. The librarian warned me that the book shouldn't be on the shelves. I didn't find out why she said that for a few years. According to the book the sun was powered by coal ! From what I can gather that was the Victorian view. When I was in my early 20's I bought a university astronomy primer. Some mention of the expanding universe - seems even Hubble him self had doubts as some of the expansions that were being measured were far too high. Also some mention of the big bang but sort of inconclusive rather than fact. That was in the late 60's. Interestingly one of Hubble's best students lost his grant recently - he was studying things that didn't fit in with an expanding universe.

Since then I read many months of SKy and Telescope on the 1st trillionth of a second of the universe - had to conclude that these people are mad.

More recently comments about light, other theories and no expanding universe crop up more an more frequently in New Scientist.

Some where along the line (years ago) I came across a theory that all elements have a critical mass and a half life. That's an interesting one.

While doing the early stages of a maths degree I came across a quote to illustrate the differences between certain sciences:

A mathematician, a physicist and an astronamer where traveling along in a train past a field with a black sheep in it. The astronomer said " All sheep are black around here", the physicist said "There is a populations of black sheep round here" and then the mathematician said "There is at least one sheep here that is black one one side".

There is a bit of a moral here. Much of physics and that end of astronomy are ideas some one has postulated and then tried to prove. Black holes came about because some one had the idea "What happens if mass accumulates to such and extent that escape velocity exceeds the speed of light". Black holes have only been indirectly detected by stars orbiting unseen objects - Who knows it might be a chunk of coal.

John

[part timer]

Ajohn,

It's nice to here a fellow sceptic!! My old Lecturer (I did Physics) was and still is profoundly against the logic of blackholes and singularities in general. He was an applied mathematician and thermodynamisist and it is true that thermodynamically black holes do run into severe problems. In addition as this lecturer was very fond of mentioning, the current number of objects currently found in the universe still equals 0. This is because no one has ever been able to show that any object fulfills the basic requirements of a blackhole. The fact that there appear to be extremely massive objects in some locations does not indicate the existence of black holes. There are alternatives such as quark stars etc which do not require a singularity.

The greatest problem as far as I can see is the overzealous application of the results of mathematics. Whilst maths can be used to describe physics, any predictions made by mathematical manipulation MUST be checked for any application in Physics. (as a very simple example when you use classical mechanics to calculate the velocity of a ball you get a quadratic equation. This give two solutions for the ball, one is at certain time after you threw the ball the other is BEFORE you threw it, which is of course meaningless) The very theoretical nature of this subject means that results are difficult to check and may not actually be valid within actual physics.

In addion a singularity is generally taken to be a mathematical entity. It is really just the point where our number system is unable to proceed, this does not NECASARILY mean that a very odd spot in space will be exempt from the same laws of physics seen in the rest of the universe.

LUKE

[Ajohn]

I know what you mean Luke. I have a healthy miss trust of people who cancel out zero's and infinities and then say well it works. I've also read too many scientific and other papers at work that have no foundation in fact. My maths by the way was just an ou foundation course, m100 the one they replaced as it was much much too hard.

My initial thoughts on black holes were "well why aren't we all in one". Then some one came up with a theory that says that they evaporate. More recently some one has been applying information theory to them. Make me wonder as in many fields the most important thing is to get ones name in print.

John

[beamer3.6m]

So if a black hole evaporates where does all the stuff within them go?

[Ant]

isn't it converted and realeased as energy?

[beamer3.6m]

That makes sense.

So effectively if you fell into a blackhole you would be turned into energy and released when it evaporated.

Surely blackholes could be a great waste/rubbish tip of the future!!! Put your rubbish in and nothing comes out, great.

[algol]

hmm call me a little scaredy cat but the word SHOULD doesn't inspire trust and confidence in my mind.

it means fingers crossed guys im gonna push the button.

also brings to mind baldrick running the damn thing, "i have a cunning plan", maybe assisted by his excellent assistant father dougal " so what's all this science stuff about then ted?"

:crybaby:

[Astroman]

I stand corrected about Einstein's cross. I have this mental image of a huge lensed comoplex with several dozen galaxies in the center every time I hear the term. Sorry.

(Boy, is this an old thread...)

http://apod.nasa.gov/apod/ap011007.html

[Ajohn]

Don't know how many of you listen to radio 4 but they have been running an astronomy program. I listened to some of it on Friday evening while driving to Pembrokeshire. Seems black holes were dreamed up in the 1790s by an english man and a french man calculated the total mass in earths needed to create one. It's interesting when you remember that one of Einsteins predictions were that gravity would bend light. Seems that they may have been aware of that a long time before he came up with it. Unfortunately they didn't how good the weight estimate was. That would have been really interesting.

John