Radical Edward

there is nothing that mathematically suggests that you can't travel at, or faster than the speed of sound though. It is just any old speed, which depends on the properties of the medium. the speed of light in a vacuum isn't.

I am not entirely sure of your train of though, but I will see what I can say. In essence, I believe you are wrong Whatever velocity you are travelling (relative to something else) light always travels at c, regardless. if you look at light coming from the sun, you will see it travelling at c. If I fly towards the sun at 0.9999999c , I will see the light coming towards me at c, so the upper limit on velocity is always c. Hence the upper limit on velocity is always c. essentially, the only thing you can use as a momentum reference, is yourself (although you could arguably project your reference point onto another object if you were doing some mathematical calculations) and the object you are measuring. nothing else matters.

they aren't all high energy particles, just some of them are. as faf said, they are just normal particle/antiparticle pairs that spontaneously come about as a result of fluctuations in the vacuum energy. fluctuations in the same vacuum energy are also responsible for so called spontaneous emission.

that's more like it.

if you can't do it, just tell the teacher that the physics of the example is completely incorrect. the wind would only apply a force in some direction which the plane would then have to overcome, directionally of course, in addition to the force required to say, maintain it's altitude and velocity. Furthermore with an additional wind speed towards the plane (or with some vector towards the plane) it would generate extra lift, picking the plane up to a higher altitude where the force yould be less. of course this is being entirely pedentic other people are giving useful answers though

oh it is a very simple paradox, and there isn'T really anything to prove the opposite, just an analysis of the error in the paradox really.

nein nein, du sprachts gutes englisch It is my German that is bad! what you are describing there, is Zeno's paradox, in which each time you get closer and closer but never reach your goal... If you fire an arrow at a turtle, each time the arrow gets to where the turtle was, it has moved on a bit, in incrementally smaller and smaller amounts, by this analysis, the arrow never hits the turtle. What you have to remember though is that each time you do this, the time increment you are measuring over is also getting smaller and smaller. so of course it will never get there. however if you measure the time in equal but finite increments each time, then you will be eating turtle soup. All I meant by the planck length/time is that those are the smallest meaningful units of time regarding Quantum mechanics, as I said, there may be a more elegant solution that explains the functioning and properties of spece more clearly to us. I am not saying that space and time are "pixellated" or anything like that

P is power in watts.

that is why mensa is mensa, because they would think of these sorts of things if the solution was easy, it wouldn't be mensa!

why not? if you were an impartial alien entity looking at the Earth a couple of million years ago, you would may well have thought that nothing on that planet would ever be capable of feelings, love, music and arts.

The Lorentz transforms are in the Relativity announcements if anyone wants them.

bah, no fluid dynamics

yeap, I thought that is what you were getting at. It just depends on the energy of the particle. Ignoring QM (since QM and black holes don't mix) a particle can escape from a distance arbitrarily close, but not on, the event horizon if it has enough energy. However, so the theory goes (Hawking I believe), black holes emit like black bodies, so they will have a characteristic black body type spectrum of emission.

well in our (sensible) eyes he has been proved wrong, but being alive a month from now with no planet showing up will prove him even more wrong. the problem is with cracks like him, is that when whatever event they are taking about doesn't come to pass, they just disappear and are never heard of again. I saw a TV interview with a guy who claimed the world was going to end in the 2000 eclipse, and so the hosts invited him to come back the day after if the world was still there. he said he would, but he never showed.

that is because the experiment was done on a human being. I will hunt it down if I have time later.

I haven't followed the exam situation much in the UK lately, but I do agree that there is too much emphasis on testing. I can understand why the government did it though - there were too many underperforming and failing schools damaging the future of children, and this really needed to be adressed. About the only way the government could really monitor the situation was through exams. The exams though will never ever count for anything, so from the student's point of view, they are a waste of time. Perhaps the government should only examine schools intermittently and randomly, with the frequency determined by how good the school has been behaving in the recent past. tests pre-gcse should not be worked towards, they should merely be a measure of how good the school is as a whole. Incidentally I thought the old A level system was a pile of cack too, because it forced too much specialisation at too young an age. I think the IB system is alot better, and should take 3 years rather than 2, with some specialisation in the final year.

as someone said "an outbreak is less terrifying than a coverup" My Girlfriend is chinese, and understandably, she is really worried about her family over there. With China itself, I think it is very difficult to disentangle the rate of spreading with the rate at which they let out cases which they forgot to talk about... furthermore, many of the chinese people aren't taking it seriously enough because of the Government cover up. Potentially though, it could become a very serious disease indeed, and I really hope that the authorities act quicky and decisively now, to stamp it out.

considering the types of drugs that are banned, I see no problem with it tbh. heroin, crack cocaine, (both very addictive, and often lethal - not something you really find in cigarettes) LSD, Ecstacy and so on. Cannabis is about the only grey area that I can think of. Beer kills lots of people, but then you really do have to drink it in excess for a long time. and the prohibition argument is largely irrelevant here. the reason that caused so many problems are somewhat different.

or rather it just means that the criminals are more likely to be armed. I like it in the UK where it is highly improbable that any potantial burglar will have a gun, and hence won't be able to kill me.

yes they should. and if you miss, then you're not good enough and should train more, not fire an automatic at bambi. Tim Henman isn't allowed to *win* wimbledon by getting an automatic tennis ball launcher firing 500rpm at his opponent.

I suggest the Emperor's nes mind and followup, Shadows of the Mind, to look at this topic. I keep suggesting it

I'm all for it, I say we give him a months grace, and maybe restrict him to pseudoscience, at which point we are either all a) dead or b) he is proved completely wrong.

As I said, it is, quantum mechanically, the smallest meaningful unit of time(length). in half a planck time(length) QM no longer applies. It may be that a more elegant and complete theory describes units of time and length shorter than this. I coudn't follow what you were saying about static time or whetever.

I can sum it up in 2: too idealistic.

the rationale behind a black hole is actually quite sensible, and what follows is a laymans guide, ignoring all the complexities. (as I don't have the time to type it all out, and my memory is a bit rusty) remember that most of everything is actually empty space. nearly all of atoms are empty, and so are the nuclei.... what holds it all int the 'shape that it is" ? a combination of Electromagnetic force and Gravity. Essentially, if you have a load of stuff like the earth, it is held up by electromagnetic forces (against gravity, which is trying to pull everything together). Gravity is a mere perturbation on the EM force over a short scale.... what happens when you have enough gravity for the EM force to be a perturbation on the gravitational field though? then the object collapses to a neutron star, with all the electrons combining with the protons to become neutrons, then the strong force comes into play. over short distances, gravity again is a mere perturbation (even on really big things like neutron stars)... until you pile up enough mass for the strong force to be a perturbaton. so the object collapses again.... but what is there to stop it from collapsing anymore now though? nothing, so it collapses to a singularity.