LHC@home

I bet they could. (neutrinios escape a black hole, that is)


http://www.telegraph.co.uk/connected/main.jhtml?xml=/connected/2005/03/30/ecfmice30.xml&sSheet=/connected/2005/03/30/ixconnrite.html

I'm not saying that I can 'prove it' using physics, hand gestures or a combination of physics and handwaving. But, if they have 'no mass' then the black hole gravity shouldn't really affect them.

So, experimentally, a neutrino is a theoretical particle which makes heavy water give of a flash of light. Neutrinos might have an issue of going throught the ground up atomic/subatomic matter inside a black hole, but I suspect that the 'no mass' aspect of neutrinos makes them great at escaping the gravity from a black hole.

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I'm not the LHC Alex. Just a number cruncher like everyone else here.

In Einstein's general theory of relativity a mass deforms the space around it and any particle moving through that space will be affected by this deformation no matter if the particle has mass or not. The theory was confirmed when it was discovered that the sun actually deflects light even though light has no mass.
If black holes did not affect massless particles, they could not exist.
A black hole is a region where light cannot escape, and light consists of massless photons.

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Chrulle
Research Assistant & Ex-LHC@home developer
Niels Bohr Institute

Hehe!

Welcome back, Chrulle!

Your reputation precedes you!

Mike W

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Gaspode the UnDressed
http://www.littlevale.co.uk

> Welcome back, Chrulle!

Thanks!

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Chrulle
Research Assistant & Ex-LHC@home developer
Niels Bohr Institute

> In Einstein's general theory of relativity a mass deforms the space around it
> and any particle moving through that space will be affected by this
> deformation no matter if the particle has mass or not. The theory was
> confirmed when it was discovered that the sun actually deflects light even
> though light has no mass.
> If black holes did not affect massless particles, they could not exist.
> A black hole is a region where light cannot escape, and light consists of
> massless photons.
>
>
>

I'm no physics person (don't flame me) but:

Isn't it that near a black hole space deforms. At the center of a blackhole there is a singularity. The answer therfore can be that light and neutrinos travel through deformed space delaying them for infinate (or finite) time.

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> I'm no physics person (don't flame me) but:
>
> Isn't it that near a black hole space deforms. At the center of a blackhole
> there is a singularity. The answer therfore can be that light and neutrinos
> travel through deformed space delaying them for infinate (or finite) time.
>

Or you could do the "No, Wait, Photons are particles too!" trick and explain it in terms of an object leaving a gravity well where that object travels at the speed of light.
It's escape velocity isn't high enough, so it falls back into the gravity well.

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I'm not the LHC Alex. Just a number cruncher like everyone else here.

> I bet they could. (neutrinios escape a black hole, that is)
...
> I'm not saying that I can 'prove it' using physics, hand gestures or a
> combination of physics and handwaving. But, if they have 'no mass' then the
> black hole gravity shouldn't really affect them.
>
> So, experimentally, a neutrino is a theoretical particle which makes heavy
> water give of a flash of light. Neutrinos might have an issue of going
> throught the ground up atomic/subatomic matter inside a black hole, but I
> suspect that the 'no mass' aspect of neutrinos makes them great at escaping
> the gravity from a black hole.
>

If I understood your question correctly, the answer is very simple - neutrinos do not have zero rest mass. They have very small one [depending on the type of neutrino - electron neutrino, muon neutrino and tau neutrino], however, not zero. This is the well known result of the recent experiments, e.g., SuperKamiokande in Japan and others.

Nevertheless, even if they have zero mass, your question is a nonsense. It is because every particle has nonzero rest mass OR at least nonzero kinetic energy. Thus, due to the theory of relativity which states that mass is equivalent to energy (i.e, mass is only something like "very pressured" energy), EVERY particle has to have nonzero mass/energy, therefore, it HAS to be affected by a black hole gravitation.

Please realize that mass is really the same as energy and vice versa. If particles with zero rest mass (like photon) would be stopped, they disappear, better said, particles with zero rest mass cannot be stopped and has to travel at the speed of light. Being stopped is the same as being nonexisting, by principles of physics and nature.

KiiroiZen / Kotulic Bunta

Member of the BOINC.SK team.

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> A black hole is a region where light cannot escape, and light consists of
> massless photons.

I thought photons have no rest mass, but they do have mass while they are moving ... Think about a ray of light that's close to the sun at an total solar eclipse ... the ray will bend! And that because of the gravitation of the sun which interacts with the mass of the photons.

Think about the no-hair-theorem of black holes. It says black holes just have a mass, charge and angular momentum.
-> if neutrinos have no mass and no charge, in my opinion they wouldnt interact with it. But as KiiroiZen / Kotulic Bunta said, they have a kinetic energy and then general theory of relativiy says that this energy equals a (small) mass m=E/c² as you know.

Just a laymens opinion ;) my physics study hasn't just begun ^^

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the only think i know about a black hole is that there mass is so huge light cant excape like if you threw some thing in the air it has to travel so fast for it to escape earths gravity and a black hole's mass is so big that something moving at the speed of light could not get out of it.

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But if a neutrino has no mass, it can then travel at a higher speed than light....

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A neutrino can not escape a black hole, nor can any other massless particle. The mass of a particle has very little effect its abillity to escape from a black hole.
Out to certain distance from the centre of a black hole the curvature of space-time is such that it is only possible to move in towards the centre of the hole. The distance where this begins to be the case is where the so called even horison lies. Anything that comes inside the even horison is trapped.

The mass, or energy, of a particle only comes into play as long as the particle is outside the even horison. Howver as long as the paricle is outside the horison it can move away from the black hole if it has sufficient velocity. All massles particles moved at rhe speed of light , and all particles with mass move at speeds striclty less than the speed of light.

What restricts the massless particles to do not travel faster than light?
Black holes attributes are mass, charge and angular momentum ... so when a particle is massless and has no charge, what restricts its movement?

Please educate me :-)

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<blockquote>>

...Please realize that mass is really the same as energy and vice versa. If particles with zero rest mass (like photon) would be stopped, they disappear, better said, particles with zero rest mass cannot be stopped and has to travel at the speed of light. Being stopped is the same as being nonexisting, by principles of physics and nature.

KiiroiZen / Kotulic Bunta

Member of the BOINC.SK team. </blockquote>

And to think that a few days ago I read about scientists being able to stop a photon, using crystals and control lasers, and then start them up again by reapplying control beams.

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I'm not the LHC Alex. Just a number cruncher like everyone else here.

<blockquote>What restricts the massless particles to do not travel faster than light?
Black holes attributes are mass, charge and angular momentum ... so when a particle is massless and has no charge, what restricts its movement?

Please educate me :-)</blockquote>

One could guess string theory could explain that.. where a particle is really just a wiggle of a string, you can't move the particle faster than you can move the wiggle wave down the string, which would be the speed of wiggle.
I think I'll trademark the phrase 'Speed Of Wiggle'.

The current state of the universe is:
String Theory - Unproven. Not Disproven. The theory itself is in a quantum state of existing and not existing and the Heisenberg Uncertainty principle will apply until it's actually measured. And even then we won't know for sure.
Neutrinos - have mass, as measured by Japanese experiments, but the Standard Model (according to the article) says it has no mass.
Standard Model - the article from my first post in this thread said that the Standard Model of physics assumed massless neutrinos.. so I guess that puts the Standard Model into question... or better yet.. a quantum state of existing or not existing.
Gravity - debate still on if gravity is a wave, or the action of messenger particles called gravitrons or something else.
Light - can be stopped, and restarted. (using crystals and control beams).
Theory of Everything - We don't have a theory of everything, because we don't know what 'everything' is... ie.. is 'everything' waves or particles or strings.

;)

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I'm not the LHC Alex. Just a number cruncher like everyone else here.

>What restricts the massless particles to do not travel faster than light?
>Black holes attributes are mass, charge and angular momentum ... so when a >particle is massless and has no charge, what restricts its movement?

This restriction is not because of the presence of tha black hole. Special relativity tells us that anything with mass must travel slowe than the speed of light, and that massless particles can travel atmost at the speed of light.

The restriction is general relativity.

In Newtonian mechanics gravity is a force acting between objects with mass. In general relativity a mass will also interact with the space-time around it, thereby changing the geometry of space. Any particle will (if you remember Newtons laws) move in a straight line if no forces act upon it. A straight line is defined as the shortest path between two points. The effect of a singularity or black hole is to deform space so much that a straight line is a circle around the black hole. This means that even massless particles, like neutrinos or photons, cannot escape the black hole.

Back to the neutrino: Modern research suggests that neutrinos do have restmass just very very little. On the order of a couple eV (electronVolts) or about a 100'000th of an electron mass. This is also necessary to allow flavour changing neutrinos. Which can explain we are seeing much fewer neutrinos from he sun than we expected.

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Chrulle
Research Assistant &amp; Ex-LHC@home developer
Niels Bohr Institute

Thanks to my private teachers :)
But I'm not sure whether my question is fully answered.

From the question we have: "If Neutrinos have no mass, can they escape a black hole?" and we assume that it cannot it would be interesting what properties a (fictive)particle must have to escape. Or is it fully excluded?

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It is fully excluded. That a particle can not escape from the inside of the event horison is not really a property of the particle. The reson it can not escape is that the "shape" of space-time is such that it is only possible to move in towards the centre of the black hole.

It is not easy to picture this pehonomenon since it does not have any very good analogues in everyday life. You might compare it to the difference between staying on a large field and being inside a tunnel. On the field you can move freely in every direction. If someone moves you into the tunnel you are suddely only free to move forward and backward. Not a perfect comparison, but at least something.

A nice popular science paper about some of the other unintuitive geometric effect near a black hole is the paper by Marek Abramowicz
<a>here


All this assumes that the particle in question has less energy than the black hole itself. If the particle is a massive object wtih energy comparable to the black hole things get a lot more tricky. In this case the particle itself begins to have a noticeable influence on the space-time curvature as well.

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Something wrong with my hyperlink aparently. It is in Scientific American, March 1993.

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<blockquote>Something wrong with my hyperlink aparently. It is in Scientific American, March 1993. </blockquote>

Abstract
<blockquote>
Black Holes and the Centrifugal Force Paradox; March 1993; by Abramowicz; 6 page(s)

If you have ever traveled in a car, bus or train as it sped around a bend, you have experienced the centrifugal force: the outward push, away from the center of the curve that grows stronger as the vehicle's speed increases. You can therefore imagine how surprised my colleague A. R. Prasanna of the Physical Research Laboratory in Ahmedabad, India, and I were when we realized recently that Einstein's general theory of relativity predicts that in certain circumstances the centrifugal force may be directed toward, not away from, the center of a circular motion. We demonstrated that if an astronaut manages to steer a spacecraft sufficiently close to some extremely massive and compact object, such as a black hole, the astronaut would feel a centrifugal force pushing inward, not outward. Contrary to everyday experience, an increase in the orbital speed of the rocket strengthens the inward push of the centrifugal force.

According to our calculations, in the region close to a black hole not only does the centrifugal force reverse direction but all dynamic effects that depend on the sense of inward and outward are also reversed. This realization is important for understanding some aspects of the physics of black holes, which are believed to be a crucial part of the mysterious central engines that power the brightest galaxies in the cosmos. Investigations of the centrifugal force paradox have provided some tantalizing insights into the behavior of these galactic energy sources.</blockquote>

Very interesting ...

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