Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 If I remember correctly according to Einstein black holes are simply made up of gravitational energy. Anything that is sucked into a black hole is converted to energy. Black holes have mass but do not contain matter and apparently are not black. Yes you can't see the black hole, and all information is lost once it's in the even horizon... Also it's the event horizon that is black, not the BH itself like you say... OK. I can comprehend that. And if I threw my old car battery in, it's mass would increase by the mass of a car battery, but it's volume would remain zero as the battery would be squished down to zero volume too....? James As far as i'm aware, yes! Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 OK. I can comprehend that. And if I threw my old car battery in, it's mass would increase by the mass of a car battery, but it's volume would remain zero as the battery would be squished down to zero volume too....? James Yes, but with a throw like that you would actually be superman Link to comment Share on other sites More sharing options...
Sheila Posted April 8, 2013 Share Posted April 8, 2013 If i'm reading this right then you're wondering why massless particles add mass to the BH? In basic terms I think that photons, although they have no mass, still have energy which is added to the BH, which increases the energy/mass of the BH (as long as the photons have more energy than the BH in the first place, which they should seeing as BH are so 'cold'!) E + mc squared so if they have energy you would have to postulate they had mass??? Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 E + mc squared so if they have energy you would have to postulate they had mass??? I thought with photons you don't use that equation? I thought their Energy was to do with the photon frequency/planks constant? (Seeing as it's to do with electromagnetic waves/quantum stuff ) Link to comment Share on other sites More sharing options...
Sheila Posted April 8, 2013 Share Posted April 8, 2013 Possibly, although whilst we're talking about photons, they do have mass they behave like particles and therefore have mass, it's just rediculously small. Actually, scratch that, Photons are said to have zero mass, but the do have momentum. However for something to have momentum it must have mass. This is an area of research that is quite a hot topic for some people. I prefer the theory that they have got some mass. it has been said that photons could have mass??? however would be very small and we have not seen The very existence of such particles is constrained by the observation of spinning black holes. With this technique, we have succeeded in constraining the mass of the photon to unprecedented levels: the mass must be one hundred billion of billions times smaller than the present constraint on the neutrino mass, which is about two electron-volts." Read more at: http://phys.org/news/2012-09-black-holes-photon-mass.html#jCp Link to comment Share on other sites More sharing options...
Sheila Posted April 8, 2013 Share Posted April 8, 2013 I thought with photons you don't use that equation? I thought their Energy was to do with the photon frequency/planks constant? (Seeing as it's to do with electromagnetic waves/quantum stuff ) whatever you use be it momentum or anything else current thinking suggest they may have mass Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 (edited) Shhhh I'm keeping with no mass! Anyway sorry for the blubber I have no idea what I'm on about because I'm Sgt. Retard when it comes to most things! Edited April 8, 2013 by Tibbz2 Link to comment Share on other sites More sharing options...
Sheila Posted April 8, 2013 Share Posted April 8, 2013 Shhhh I'm keeping with no mass! Anyway sorry for the blubber I have no idea what I'm on about because I'm Sgt. Retard when it comes to most things! so do i actually, its much easier and things work much better Sheila Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 Everything i've ever learnt/read/seen has used massless photons so until proven otherwise I'll stick with it, much easier like you say! Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 I'm sticking with an immeasurably small mass since it makes other bits of physics easier if they have. Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 I was wondering how something falling into a BH goes back in time? I know their clocks slow down the closer they get relative to other observers but how does this make them go backwards in time? I can see it does, I just can't explain it to myself (if that makes any sense!) Link to comment Share on other sites More sharing options...
Sheila Posted April 8, 2013 Share Posted April 8, 2013 I was wondering how something falling into a BH goes back in time? I know their clocks slow down the closer they get relative to other observers but how does this make them go backwards in time? I can see it does, I just can't explain it to myself (if that makes any sense!) nope.... i thought space/time ceased to exist at a singularity. Time is only relative? Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 (edited) I think I got it the wrong way round I meant travelling into the future - Edit: Actually, I have no idea. But i'm pretty sure one of them is allowed in Eintein's theories and one of them is not.... Whichever is allowed is what I meant! I just remembered it's all to do with time dilation brought on by gravity, like how the people in the ISS age slower than us on Earth etc. Just me getting mixed up again Edited April 8, 2013 by Tibbz2 Link to comment Share on other sites More sharing options...
dawson Posted April 8, 2013 Share Posted April 8, 2013 I think you are all very clever. I feel very astro-inadequate lol James Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 I think you are all very clever. I feel very astro-inadequate lol James This is the whole point of this section of the forum, so we can ask questions and have them answered / discussed Until last year I knew nothing much about astro related stuff, I had an understanding of physics though which I guess helps a lot. Stick around, we'll all learn from eachother Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 I'm certainly not that clever, I'm just interested in this stuff Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 I think I got it the wrong way round I meant travelling into the future - Edit: Actually, I have no idea. But i'm pretty sure one of them is allowed in Eintein's theories and one of them is not.... Whichever is allowed is what I meant! I just remembered it's all to do with time dilation brought on by gravity, like how the people in the ISS age slower than us on Earth etc. Just me getting mixed up again Did some reading and that's what I was on about. Basically you're kind of travelling in time slower the closer you get to the black hole, so you will age slower than someone further from the black hole. Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 Did some reading and that's what I was on about. Basically you're kind of travelling in time slower the closer you get to the black hole, so you will age slower than someone further from the black hole. Not actually true. In the lecture I linked to (I think, if not then another from the same series) the example is given of somebody flashing a torch as they get pulled into a black hole to a person outside of the event horizon. Although the person being pulled in would be constantly flashing it at say a rate of once a second, that rate would appear from the outside to have slowed by an increasing amount the further in they were pulled. Time is relative to the observer. The person being pulled in would not be aware of any slowing of time as things would be happening just as fast or slow as always to their knowledge and experiences, however to those observing from outside it would appear to have slowed in comparison to that persons surroundings. If any of that makes sense. Of course, flashing a torch at regular intervals would be the last thing on my mind if I were being pulled into a black hole..... I'm guessing one of two things would be crossing my mind: 1, hmmmmm KFC, and 2, did I leave the iron on? Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 (edited) Yes I know light being pulled back/slowed by the increasing gravitational force, but due to time dilation you actually age slower is what I have been reading? :s Am I missing something? Edit: Clocks which are far from massive bodies (or at higher gravitational potentials) run faster, and clocks close to massive bodies (or at lower gravitational potentials) run slower. So is this 'relative'? Edited April 8, 2013 by Tibbz2 Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 Relative to those outside in theory then yes. By your own experience from being in there then no, time will not seem to slow down for you. Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 (edited) Removed: Nevermind I've looked back and notice I've been asking some idiotic stuff due to my own confusion. Cleared myself up now lol Sorry Edited April 8, 2013 by Tibbz2 Link to comment Share on other sites More sharing options...
dawson Posted April 8, 2013 Share Posted April 8, 2013 People on the ISS after a stint up there will have aged less than the rest of us over the same period, but the difference is miniscule. If the difference were much greater, you would probably live for longer (in our terrestial earth years) than if you lived on earth, but i susepect the inceased cosmic radiation would increase your risk of various cancers that you'd die younger. James Link to comment Share on other sites More sharing options...
Perkil8r Posted April 8, 2013 Share Posted April 8, 2013 People on the ISS after a stint up there will have aged less than the rest of us over the same period, but the difference is miniscule. If the difference were much greater, you would probably live for longer (in our terrestial earth years) than if you lived on earth, but i susepect the inceased cosmic radiation would increase your risk of various cancers that you'd die younger. James The difference is approx 0.007 seconds over a 6 month period. Link to comment Share on other sites More sharing options...
dawson Posted April 8, 2013 Share Posted April 8, 2013 Exactly, a minuscule amount. Jd Link to comment Share on other sites More sharing options...
Tibbz2 Posted April 8, 2013 Share Posted April 8, 2013 (edited) Yes that was the effect of time dilation I was on about. Which I guess would be far greater around black holes due to the massive amounts of gravity. The thing I was querying was just me misunderstanding something else, that's why I was confused Edited April 8, 2013 by Tibbz2 Link to comment Share on other sites More sharing options...
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