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Thread ID: 55052	2005-03-01 10:10:00	Teleportation / Time travelling...	Renmoo (66)	PC World Chat

Post ID	Timestamp	Content	User
329525	2005-03-11 03:30:00	Now I some sort of get it, e=mc2, if we can travel at the speed of light multiply speed of light, which we would never be able to do so, we would turn into energy. Energy and death both are closely related. We you die, your body decompose and release all the "nutrients". Now, that applies to if we travel at c*c. What if we manage to travel at speed of light? Will we turn into energy? One more confirmatory fact question, earth does not affect the flowing of time, does it? Apparantly it helps if you have a DeLorean (dont forget the flux capacitor). which must be able to acheive 88 mph (this saves you having to travel the speed of light). Failing that you can e-mail Dr. Who at dr?@yahoo.com and ask if you can borrow the TARDIS. Veale	Veale (536)
329526	2005-03-11 03:39:00	Apparantly it helps if you have a DeLorean (dont forget the flux capacitor). which must be able to achieve 88 mph (this saves you having to travel the speed of light). Failing that you can e-mail Dr. Who at dr?@yahoo.com and ask if you can borrow the TARDIS. Veale The DeLorean was made in Ireland,which may account for that minor idiosyncrasy.	Cicero (40)
329527	2005-03-11 07:47:00	Could the increase in mass of an object as it approaches the speed of light be related to something else . How is this increase in mass measured . It's not like you can an sit an electron on a set of scales as it wips round a accelerator and see the increase . Are we assuming that the the object is increasing in mass because it needs more energy to make it go faster, or is there a way of measuring the increase . I'm thinking this because (and I will not be at all surprised if I find that I am WAY off track but), as an object is pushed towards the speed of sound, it requires more energy to get it through the sound barrier (i can't remember the figures) than it would require to stay just below it or above it) . Once through the sound barrier, it does not need the same amount of energy to maintain it above the sound barrier as it need to get it through . To put it like the text books, supersonic air flow on an object behaves in a subsonic manner, or something like that . Could an object trying to attain light speed, have to overcome some as yet undiscovered force which, once broken through, would then permit travel at speeds in excess of light, or am I just a good science fiction writer .	craigb (4884)
329528	2005-03-11 09:04:00	>>How is this increase in mass measured. It's not like you can an sit an electron on a set of scales as it wips round a accelerator and see the increase.<< A study of the physics of the cyclotron will demonstrate how the mass of an electron being accelerated in a spiral under the influence of magnetic and electric fields increases as the speed get high, as predicted by Einsteins theory of relativity. The actual basic maths of what should happen in the absence of relativistic effects is fairly simple, then the departure of the motion of the electron from simple theory gives the effective mass change. www.physics.rutgers.edu www-nsd.lbl.gov There is no connection or similarity with sonic/super-sonic flight. The term "sound barrier" is a misnomer, a popular phrase coined in the late 1940s to describe the problems encountered at that time when a plane designed for sub-sonic flight tried to exceed the speed of sound. Remember that supersonic aerodynamic knowledge at that time was somewhat limited. Subsonic plane aerofoils have rounded leading edges, and a detached shock wave will form in front of the leading edge, and drag is high. For supersonic flight and low drag a sharp leading edge is required. There isn't a light barrier to be overcome. All knowledge to date says that the speed of light cannot be equalled or exceeded by a body having mass. All other speculations are in the realm of science fiction, ie the realm of unverifiable belief, but something most humans seem to have a need for.	Terry Porritt (14)
329529	2005-03-11 17:11:00	Now as the electrons got up to about 0.9 the speed of light, or there abouts, they started to get heavier, as predicted by Special Relativity, the energy required to accelerate them started to rise steeply. Hey Terry, thanks for your nice article on this Special Relativity. So, I guess your point is that as an object is reaching the speed of light, the energy required to move it increases sharply. What causes this scenario? From your reply, I presumed that no matter can achieve the speed of light. How about light? How did light achieve speed of light? Is there any article on how light travel at such a high speed? Cheers ;)	Renmoo (66)
329530	2005-03-11 18:56:00	Hey Terry, thanks for your nice article on this Special Relativity. So, I guess your point is that as an object is reaching the speed of light, the energy required to move it increases sharply. What causes this scenario? From your reply, I presumed that no matter can achieve the speed of light. How about light? How did light achieve speed of light? Is there any article on how light travel at such a high speed? Cheers ;) We just have to accept that light is, well, just light, and observe what it does. It does not have mass only energy and wavelength. It is an electro-magnetic radiation. The maths we use to try to describe it are not perfect. Sometimes it is convenient to say it consists of particle like packets called photons, at other times is is more convenient to say light is like a sine-wave and use wave theory to describe its behaviour. Though we say light has no mass, it does get bent in a gravitational field, also as predicted by Einstein, and this can be observed astronomically. Observations on the planet Mercury were I think the first to demonstrate bending of light passing near to the sun. Your library may well have some text books on light. I found this excellent site that talks about GPS, clocks and relativity: www.metaresearch.org	Terry Porritt (14)
329531	2005-03-11 22:52:00	Though we say light has no mass, it does get bent in a gravitational field, also as predicted by Einstein, and this can be observed astronomically . Observations on the planet Mercury were I think the first to demonstrate bending of light passing near to the sun . Just musing here Terry, because I am no physicist (hell, I can only just spell it!) but wouldn't the influence of gravity on the path of light be an electrical or electromagnetic field effect acting on the energy of the light rather than its mass? The solar sails that NASA is using (or proposing to use) to accelerate unpowered spacecraft to very high velocities also bear thinking about . Musing further, if light has no mass, then how can it impart energy to the spacecraft? If it is pure energy, what form does the energy change in the propelling light take? Of course if light had mass, since it travels at the speed of light (what else could it do anyway?) it would have to be of infinite mass, which would make it rather heavy . This suggests that the flat-earthers may be right . Maybe that infinite mass of sunlight impacting on the Earth has flattened it out into a pancake? Of course, that then begs the question: if the Earth is flat, and we are on top, what is on the underside of the Earth? Maybe the flat-earthers have overlooked this point, as I don't recall reading any learned dissertations on the subject . I guess the Creationists would say Hell, but there is plenty of that here on the top side so it would be a bit redundant . Maybe we should tilt the Earth up on its edge then start it rotating, then we could share the sun 50-50 with the other side and in time the pressure of the infinite mass of the Sun's light would press the planet into a sort of rotating ball shape . But that was where I came in :help: Cheers Billy 8-{) :D	Billy T (70)
329532	2005-03-12 00:41:00	Light and other electromagnetic radiations exert a pressure on a reflecting surface. It is easier to think of light photons as similar to small particles, which as in the kinetic theory of gases will exert a pressure on a surface due to collision and changing momentum. The threads are so long now, can't remember, but I think it was Cicero who mentioned that light photons (which have an "equivalent" mass of h.v/cxc), exert a pressure of h/λ, where h=Planks constant, v=frequency, c=velocity of light, λ=wavelength. The wave theory of light can also be used to derive radiation pressue. The equivalent mass of photons is incredibly small because of dividing by c squared, that's why light is said to have no mass. It isn't mass in the sense of the mass of electrons, neutrons or protons, ie ordinary matter, but it is enough effective mass to give rise to 'gravitational lenses' in astronomy. Light coming from behind large dense black bodies or galaxies and being bent around them (or something like that). So within the solar system it would be feasible to have large sails, on which the solar 'wind' and light will exert a small continuous pressure to gradually increase the speed of a craft. Incidently this isn't my field at all, I was into rotating machinery, bearings , fluids, precision engineering and metrology. I'm sure a recent physics graduate would say what a load of old fashioned baloney :)	Terry Porritt (14)
329533	2005-03-12 01:39:00	Fluids, precision engineering and metrology. :) In that case,why does some copper go black in the air,whilst other goes green? This can be observed at the ch ch town hall,where it is black,where as my weather cock has gone green.	Cicero (40)
329534	2005-03-12 01:39:00	The equivalent mass of photons is incredibly small because of dividing by c squared, that's why light is said to have no mass. It isn't mass in the sense of the mass of electrons, neutrons or protons, ie ordinary matter, but it is enough effective mass to give rise to 'gravitational lenses' in astronomy. Thanks Terry The words "enough effective mass" is about the point where my head implodes. :dogeye: I had less trouble reading Stephen Hawkings' books.:( I can't get past the concept that mass is mass is mass, so I shall go and have a lie down and a cold compress I think. Cheers Billy 8-{) :stare:	Billy T (70)
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