Delacorr Posted June 18, 2003 #1 Share Posted June 18, 2003 What would happen if you were traveling faster than the speed of light and were to look behind you? Would you see the light trailing behind or what? Would you be suspended in time and space? What are your thoughts? Link to comment Share on other sites More sharing options...
Homer Posted June 18, 2003 #2 Share Posted June 18, 2003 The only time I travel faster than light, is when I’m on my way to see my darlin’ When that happens, I’m only looking ahead Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #3 Share Posted June 18, 2003 Delacorr, I'm not sure anyone can give you an answer to that, the best we can do is speculate, but there is no definitive answer. If a spacecraft lets say, was travelling at a speed comparable to that of light, then time, to the astronauts on board, will be going at a different rate from time on the earth. So at a sufficient speed, whereas 50 years may pass on the earth, the astronauts in the spacecraft may have only aged 5 years. If we then crank up the speed to the speed of light ( if it's at all possible ), we can only guess at to what will happen inside the spacecraft. Time may not pass at all for the astronauts, basically meaning that no matter how long they travel for from the perspective of someone on earth, no time at all will pass for those on board. If you then exceeded the speed of light, who knows. They probably wouldn't be suspended in space, but inside the craft, time could actually be going backwards. If that's the case, they'd be younger when they got to their destination that when they left the earth, even if they'd been going for 3 million years. It's really quite bizarre when you think about it. Link to comment Share on other sites More sharing options...
Althalus Posted June 18, 2003 #4 Share Posted June 18, 2003 Ok this may seem like a thick question, but, why can we not go the speed of light, and I know about E=MC2. After all, If light can travel at that speed why can't we? If the answer is, that light has no mass, I would say that it does, otherwise we would not able to see it. Link to comment Share on other sites More sharing options...
Halo_Jones Posted June 18, 2003 #5 Share Posted June 18, 2003 Ooopppps wondered in to the Brain pain zone. Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #6 Share Posted June 18, 2003 Al, The reason we can't reach the speed of light, is because the closer we get to that speed, the greater the mass of the object becomes. Therefore the energy needed to accelerate the object to a greater speed becomes proportionally greater aswell. Eventually the mass goes to infinity - requiring an infinite amount of energy to get the speed of the object any higher. Because of this it is thought impossible to actually travel at the speed of light itself. I'm not convinced it is known for a fact whether or not light has mass. Visible light, which is part of the electromagnetic spectrum, consists of 'photons', and it is generally thought that photons do not have mass. Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #7 Share Posted June 18, 2003 But the speed of light is not infinite, so an infinite amount of energy is therefore not required. The difference between an infinite amount of energy and just a vast amount of energy is, well, infinite. So if not an infinite amount of energy, how much energy would it actually take? Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #8 Share Posted June 18, 2003 Aslan, The speed of light is not infinite as you say, but the mass of the object your trying to move at the speed of light becomes infinite as it approaches light speed. It is to further accelerate this object of infinite mass that you need the infinite energy for. Since an infinite amount of energy is not available, nothing with non-zero mass can ever reach the speed of light itself, as far as we know. Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #9 Share Posted June 18, 2003 Aha. Got it. I'm still a little fuzzy on just WHY the object would attain infinite mass. The whole concept of gaining mass with speed I understand, but INFINITE mass? I can't quite grasp how something finite can slowly become infinite, for whatever reason. Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #10 Share Posted June 18, 2003 I agree, I don't think anyone really knows why it happens either. Similarly there's no real explanation for why the faster an object is moving, the slower time passes for that object, and the shorter that object becomes. Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #11 Share Posted June 18, 2003 Similarly there's no real explanation for why the faster an object is moving, the slower time passes for that object, and the shorter that object becomes. Is that true for sound and light waves aswell? (And if that quote from SaRuMaN doesn't come out right, could someonw tell me how to quote. Another mystery of the universe.) Link to comment Share on other sites More sharing options...
FreyKade Posted June 18, 2003 #12 Share Posted June 18, 2003 its just like when you are on a rollercoaster, when you go down a slope, very fast, you feel heavier Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #13 Share Posted June 18, 2003 (edited) Aslan, Sound waves are just waves, the speed of sound waves can change depending on the medium the waves are passing through. Light 'waves' are a controversial subject, as light exhibits behaviour consistent with both waves and particles. 'Photons' are described as being 'chopped up pieces of wave', and are regarded as being what light consists of. You can't really apply time dialation and length contraction to light or sound, sound waves in particular are not even part of the electromagnetic spectrum. I suspect these phenomena are only applicable to physical objects with non-zero mass. * Edit - Sorry forgot to mention how to add quotes You need to have two quote tags on either side of the text you wish to quote. For example : [QUOTE]This is a quote[/QUOTE] Remember to add a / in the second tag to indicate that it's the end of the quote. Edited June 18, 2003 by SaRuMaN Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #14 Share Posted June 18, 2003 God, it's just bizarre (bizzare?) , isnt it. So what does sound consist of? Sound waves are just waves What does that mean, just waves? And what about other kinds of waves? What do they consist of? And I still can't grasp how something that exists in an objective sense, as sound waves demonstrably do, can have zero mass. My father was a physics teacher you know. I'm adopted. Link to comment Share on other sites More sharing options...
Saru Posted June 18, 2003 #15 Share Posted June 18, 2003 Aslan, Sound waves are basically vibrations, that can travel through a medium such as through air, or through water - but not through a vacuum. Visible light is a type of electromagnetic wave, which is a wave of oscillating electric and magnetic fields. Other electromagnetic waves include radio waves, microwaves, infra-red waves etc. Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #16 Share Posted June 18, 2003 Then surely light has mass? If a sound wave consists of nothing, and therefore had no mass, a light wave, which consists of SOMETHING, must have a mass. I am being dim? Link to comment Share on other sites More sharing options...
Homer Posted June 18, 2003 #17 Share Posted June 18, 2003 Light consists of photons, which are particles that don’t have mass Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #18 Share Posted June 18, 2003 How? Link to comment Share on other sites More sharing options...
Delacorr Posted June 18, 2003 Author #19 Share Posted June 18, 2003 Here's another one...does the speed different colors of light vary too? Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #20 Share Posted June 18, 2003 I mean, I understand that a sound wave is, basically, some kind of disturbance in the surrounding matter, therefore it has no mass, but how can you say a photon is an objective and distinct thing and yet it had no mass? Light consists of photons, which are particles that don’t have mass This is all well and good, but prove it, because I just don't see how it's logically possible. If you can't prove it then somebody explain the reasoning behind it. Link to comment Share on other sites More sharing options...
Delacorr Posted June 18, 2003 Author #21 Share Posted June 18, 2003 Aslan you have a point but as a MATTER of fact...i think Homer may know what he's talking about..(no pun intended!) Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #22 Share Posted June 18, 2003 I bow to Homers knowledge, but is there no place for childlike and guileless wonderment? No disrespect to Homer but I'd still like someone to explain to me how light has no mass. I'm not prepared to except a given statement because it's postulated (that one's for you, Kismet ) as scientific fact. I just don't understand, that's all. Link to comment Share on other sites More sharing options...
Delacorr Posted June 18, 2003 Author #23 Share Posted June 18, 2003 Aslan, Light does not have mass, at least not in the usual physics definition. To be specific, light has no rest mass— the mass that something would possess if it were brought to a stop. All the same, light is affected by gravity. The reason for this is a very important physics concept known as the equivalence principle. In a famous experiment, Galileo dropped two objects of different masses from the Leaning Tower of Pisa and saw that they fell at the same rate. He concluded that gravity affects all objects the same way, regardless of mass. Modern experiments have confirmed that the equivalence principle applies to everything, even to light. When starlight passes near the sun, it is bent by gravity, and light traveling upward from Earth's surface loses energy as gravity tries to pull it back. If that helps... Link to comment Share on other sites More sharing options...
Aslan Posted June 18, 2003 #24 Share Posted June 18, 2003 Then how can you tell me light has no mass? Does the equivalence principle apply to sound? If it's effected by gravity it must have mass. Sound waves aren't effected by gravity Link to comment Share on other sites More sharing options...
Delacorr Posted June 18, 2003 Author #25 Share Posted June 18, 2003 So then sound waves dont have mass right? Link to comment Share on other sites More sharing options...
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