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A good programmer is someone who looks both ways on a one-way street

well if an atom is basically made up of protons and neutrons fused together usually you cant get much past 300 until they get too unstable to exist long enuff but a neutron star uses the sheer gravitaional force to hold them together cos they are literally just below the neutron repulsion limit (otherwise it'd be a blackhole) so there you have it my theory that a neutron star is the biggest atom possible

>:]

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Hey DKB shu'p with all that jibba jabber ya crazy foo!

ALL YOUR ELECTRONS ARE BELONG TO US

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-- incubus
As I chase the leaves like the words I never find ...

A point to ponder, if the Earth was squished done to a 25 mm diametre sphere (thats an inch for all you Americans...), then you'd get a black hole. (Thats a first order calculaion BTW)

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"All is number" - Pythagoras

quote:

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Originally posted by masher:
A point to ponder, if the Earth was squished done to a 25 mm diametre sphere (thats an inch for all you Americans...), then you'd get a black hole. (Thats a first order calculaion BTW)

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This is from Hawking's "A brief history of time"..

the physicist John Wheeler once calculated that if one took all the heavy water in all the oceans of the world, one could build a hydrogen bomb that would compress matter at the center so much that a black hole would be created. (Of course, there would be no one left to observe it!)

damn we're smooth

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"Here at Borger King, we do it our way. Your way is irrelevant."

My physics is rusty, but the idea is there.

Edit: I all messed up that mofo.

This message has been edited by askheaves on February 23, 2001 at 06:15 PM

darkknightbob made it sound like a neutron contained an electron and a proton, which it doesn't.

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Originally posted by aventari:
This is from Hawking's "A brief history of time"..

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That may be true, but it is the result of one of my calculations, which is why its first order...

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"Make things as simple as possible, but no simpler" - Einstein

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Hey DKB shu'p with all that jibba jabber ya crazy foo!

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"Make things as simple as possible, but no simpler" - Einstein

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Free neutrons undergo beta decay with a mean lifetime of about 10 minutes

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The key word here is 'free'. That is, a neutron all by itself. After about 10 mins, it will spit out an electron and transform into a proton.

.

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The density of a neutron start is about 1.2x10^14 gcm^-3 ... slightly less than the density of a neutron, which is about 4x10^14 gcm^-3 ... we can conclude that the gravitational pressure of the neutron star is balanced by the repulsive component, due to the exclusion principle, of the strong nuclear force between the neutrons.

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Tipler, P.A, 1992, Elementary Modern Physics, Worth Publishers, New York, pp. 314-315.

Also, a neutron star with the mass of our sun will have a radius of 12.7 km. As the mass increases, the radius decreases, until you get a black hole. About 1.7 - 3 solar masses is the limit for neutron stars. After this you get black holes.

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"Make things as simple as possible, but no simpler" - Einstein

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-- incubus
As I chase the leaves like the words I never find ...

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Hey DKB shu'p with all that jibba jabber ya crazy foo!

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A Physics major asks "Why does it work?"
An Engineering major asks "How does it work?"
A Buisness major asks "How much will it cost?"
A Liberal Arts major asks "Do you want fries with that?"

Sub atomic stuff is so annoying that you might aswell see a proton as a neutron and an electron together anyway, it saves time.

Anyway, lets talk about the good shit. Super massive black holes! And when they collide! could you work out the energy released by the collision please, incubus, please?
cheers

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Originally posted by incubus:
Thats called the Chandresekar limit

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That it is...

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Originally posted by LazyGit:
Yeah, but in real world (space) conditions the star would really need to be over 5 times stellar mass to have a chance of turning into a black hole.

Sub atomic stuff is so annoying that you might aswell see a proton as a neutron and an electron together anyway, it saves time.

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Depends on the conditions in which the star dies. I'm not an astrophysicist, but 1.7-3 solar masses for an upper limit for the formation of neutron stars is a large range, so I wouldn't be suprised if larger stars did form neutron stars instead of black holes, but I don't think you'd need >5 solar masses to have any chance, just >2 would be enough.

Or a neutron as a proton plus an electron maybe? Just because something decays into something else, doesn't mean that it is composed of soley of the decay products. In order for it to decay, it must be energetically favourable. This means that energy is 'lost' in the transformation, so you can't say that a neutron is a proton plus an electron.

edit: UBB greebles

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"Make things as simple as possible, but no simpler" - Einstein

This message has been edited by masher on February 26, 2001 at 03:30 AM

Very large stars explode though so they're going to throw off a lot of their mass in the supernova. The star's got to have enough mass to be able to lose a lot of it but have enough left to leave its gravitational radius large enough for it to be able to collapse through it.
cheers

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Fucknuggets flamed while you wait.< TeamWolfguard.com >

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"I ated the purple berries...they tasted like burning"

'cept me of course.

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A Physics major asks "Why does it work?"
An Engineering major asks "How does it work?"
A Buisness major asks "How much will it cost?"
A Liberal Arts major asks "Do you want fries with that?"

but since science deals really poorly with singularities, gotta wonder, are there white holes out there?

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kuru
'dancing is the vertical expression of horizontal desire.'
-robert frost

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Originally posted by kuru:
black holes are pretty interesting buggers... all that bending of space time and all. who the hell even knows what would happen if a person went into one?

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He would get really really small...

This message has been edited by Wolfguard on February 28, 2001 at 05:40 AM

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Originally posted by kuru:
but since science deals really poorly with singularities, gotta wonder, are there white holes out there?

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From what i remember. a particle of any size can come into existance from nothing at any given point at any given time. If a particle that has enough mass could start to under go gravitational collapse causing a chain reaction that would throw matter in all directions(explosion). If the conditions that caused that particle to come into existance in the first place stayed at that location it would continue to throw matter untill the conditions changed.

I think this is what is called a white hole.

now if i could remember where that came from i would be doing good. It may be from collage. All i know is it sounds smart so it cant be an original thought of mine

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Fucknuggets flamed while you wait.< TeamWolfguard.com >

singularities are caused by inconsistancies in theories and math dealing with the standard model, which as of recently has become challenged. it looks as if the string theory will finally get the credit it deserves.

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Originally posted by Wolfguard:
now if i could remember where that came from ...

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I'd put my money on Trek. Surprised some dilithium crystals didn't make an appearance.

:P

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Originally posted by CatKnight:
'cept me of course.

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Don't worry chrissy. Modesty is a virtue. You'll never catch me telling you how good I am, except when I do.

Four years of physics at uni plus another 3.5 to go (PhD) is enough to send anyone bonkers...

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"Make things as simple as possible, but no simpler" - Einstein

and no singularities are 0 size, thats the point. we can only calculate them to the point where they are very very very small, but according to the standard model they should be zero size.

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Originally posted by kuru:
black holes are pretty interesting buggers... all that bending of space time and all. who the hell even knows what would happen if a person went into one?

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The existence of a black hole is really only a theory as of yet, but the theoretical black hole is just a massive amount of gravity that sucks anything and everything into it (nearby planets, stars, even light itself). So a person would be crushed before they even got close enough to "enter" it...

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If the doors of perception were cleansed everything would appear to man as it is, infinite. - William Blake

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Originally posted by hair:
The existence of a black hole is really only a theory as of yet, but the theoretical black hole is just a massive amount of gravity that sucks anything and everything into it (nearby planets, stars, even light itself). So a person would be crushed before they even got close enough to "enter" it...

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black holes have been proven to exist. although they have not been directly observed (which would be very difficult if not impossible), we can observe their effects. if we see 1 star orbiting around something else we can't see, we can determine the mass of the unknown object by the way the regular star orbits. several objects have been found to have masses larger then the chandrasekhar limit. the best blach hole candidte is Cyg X-1.

a black hole is not just a 'massive amount of gravity', it is the core of a collapsed star whos mass is so large that light is curved so much that it just curves into itself, and can't escape (the event horizon). einstein's theory of relativity was proven by looking at the sun during an eclipse and observing a slight curvature of space right around the sun (stars right near the sun appeared to bend inwards). a black hole is the same thing but much stronger.

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What would you see if you went right up to a black hole? Above are two computer generated images highlighting how strange things would look. On the left is a normal star field containing the constellation Orion. Notice the three stars of nearly equal brightness that make up Orion's Belt. On the right is the same star field but this time with a black hole superposed in the center of the frame. The black hole has such strong gravity that light is noticeably bent towards it - causing some very unusual visual distortions. In the distorted frame, every star in the normal frame has at least two bright images - one on each side of the black hole. In fact, near the black hole, you can see the whole sky - light from every direction is bent around and comes back to you. Black holes are thought to be the densest state of matter, and there is indirect evidence for their presence in stellar binary systems and the centers of globular clusters, galaxies, and quasars.

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Singularities aren't zero size, they're just very very very very small. And if God did divide anything by zero wouldn't it just say "Error 2" in the middle of the galaxy. That's what my calculator does anyway.
cheers

quote:

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Originally posted by askheaves:
I'd put my money on Trek. Surprised some dilithium crystals didn't make an appearance.

:P

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Nope
Quantum Physics book. Found it last night :P

Still makes my head hurt.

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Fucknuggets flamed while you wait.< TeamWolfguard.com >

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Hey DKB shu'p with all that jibba jabber ya crazy foo!

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Hey DKB shu'p with all that jibba jabber ya crazy foo!

practically though, neutron stars are either accreting matter from a binary, in which case the surface would be burning white hot, or are ejecting material/light from nearby dust and such therefore beaming out radio jets like the VELA pulsar does.

Okay, not that interesting.
cheers

Ripped off hey?

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"Make things as simple as possible, but no simpler" - Einstein