can someone explain to me what a tachyon is?
345074
Tachyon is the name given to any hypothetical particle that would move faster than the speed of light.  They may exist, but we have never detected them, and if theory holds we can't.  The speed of light is an "upper limit" on the propagation speed of normal particles and particle-like things that we deal with, if you add energy to a particle it goes faster.  Tachyons on the other hand have the speed of light as a "lower limit" of propagation, and as they gain energy they travel slower.
50897
It's kida hard to explain comprehensively in 1000 characters or less, so the next best thing I can do right now is put a link to a website that explains the  diferences in layman's term in the source below.\nHope that helps you out.
1014651
It is real.  We can measure the life of a muon here on the surface of the earth, but according to calcuations, this lifetime is much shorter than what we measure.  However, these muons are created in the upper atmosphere and move at relavatistic speeds.  Time dialation explains the increase in time.  Since they are traveling very fast, then time slows down and they appear to live longer!
992429
Hi bornsmartgal\n\nThe antimatter created in the very early universe annihilated with matter created at the same time.  When a matter particle and its antimatter counterpart meet the annihilate and produce energy (eg a collision between an electron and positron produces two back to back photons).  In the early universe there was a small over abundance of matter over antimatter (one billion and one matter particles for every one billion antimatter particles).  After the annihilation this leaves matter left over (plus a billion photons for every matter particle!)\n\nThis initial over abundance of matter over antimatter is puzzling - the difference between matter and antimatter is a reversal of charge and particle physics is largely symmetrical to charge reversal. Physicists have been looking for an asymmetry in nature which will explain the over abundance, and have finally found a few such events (called charge-parity symmetry violations).  It appears nature isn't totally symmetrical after all.\n\n\nHope this helps!\nThe Chicken
612849
NO energy, matter, or information has EVER been observed to exceed the speed of light.\n\nTheoretically, there are particles known as "tachyons" ( see wikipedia ) that travel ALWAYS in excess of that of light but never AT or BELOW that speed. Although never observed, their theoretical existence has sent many physicists to look for them ( or their trails ! ) \n\nthere are many abstract entities that "travel" faster than light.  for example, the shadow of a large celestial object ( a planet say ) on another celestial object can be observed to move at great speeds.  a shadow however is not a real entity ( i.e. mass or energy ) and it cannot convey information.
325710
I can't help with Unified Theory, but here's the way a professor explained string theory to me.\n\nImagine that you have a tightrope, and that an elephant is walking on it.  To that elephant, there is only one dimension - the elephant can move forward, and it can move backwards, but it can only move along that straight line.\n\nNow picture that same tightrope, but instead of an elephant, an ant is walking along it.  Like the elephant, the ant can also move forwards and back along the tightrope.  However, the ant can also walk all the way around the tightrope (apparently ants are good at clinging to things while upside-down).  For the ant, there are two possible dimensions - the forward and back one, and the around one.\n\nString theory is basically the idea that there are more dimensions than we realize.  We as humans are the elephant of the previous example - we see only three dimensions, with a potential 4th in terms of time.  According to string theory, there are ants in the world that can access more than these three or four dimensions that we are aware of.  String theorists are currently trying to prove that this is the case.
1048247
There may be objects (tachyons) that move faster than light, up to perhaps infinite speeds.\nHowever, nothing already slower than light can accelerate to or beyond the speed of light.
323857
i think tachyons are only hypothetical and have never actually been observed. the definition of a tachyon is particle that moves faster than light. any particle with positive mass can never move at the speed of light because mass increases with velocity and would become infinite at the speed of light. photons, which make up light, have no mass so they move at the speed of light. a tachyonmust have less than zero mass; it must have imaginary mass - a mass expressed in terms of the square root of -1. i'm pretty sure that these particles have never really been observed, but you might want to look a little further.
117056
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in a physical theory. Studies of string theories have revealed that they require not just strings but also higher-dimensional objects.
1011227
Love to give you specifics, but don't know how.\n\nTheoretically, what you suggest is possible by relativistic theory. There are things called "tachyons" which are these kinds of rays which reverse time - well not "reversing" it, but definitely messing it all around.  Einstein said that nothing could accelerate to faster than speed of light without becoming infinite mass - but "...Einstein said nothing about entities already traveling at that speed or greater..." (Prote in K-Pax).  \n\nSo who knows - is it around the corner for us?  Probably not.  Is it possible?  I love this universe, so I say yes.  Keep surprising me...
489410
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in a physical theory. Studies of string theories have revealed that they require not just strings, but also higher-dimensional objects.
614330
It sounds like you are talking about an area of science known as quantum mechanics, though you might be referencing subatomic particle theory.  Yes, the math can be a bit much and the conceptualizations a bit forced.  But not knowing you I am hestitant to say no way.  Maybe you could should start out with little thermodynamics.\n\nThe first site below is one called HyperPhysics.  The link will send you straight to the grid on thermodynmics.  Try tapping the buttons, read and little and see if it makes sense.  I suggest you start with kinetics.  If HyperPhysics doesn't do it for you, try Wikipedia.  If you want to leap in head first the last reference is about string theory, tachyons and all that good stuff.  Good luck and heppy learning.
392295
http://en.wikipedia.org/wiki/String_theory\n\nI know giving a url as an answer is a cop out, but really, it is the best way to explain something as complex as the string theory. READ IT! It's pretty cool!
161235
A graviton is the name. The existance of this particle has´n´t been confirmed yet but hopefully it will be soon.
157544
Well it is a bit technical, but let me try.\n\nThe equations of special relativity include a term that looks like gamma=sqrt[1-(v/c)^2] where v is the speed of the object, and c is the speed of light. The equations for relativistic mass. The equations for relative position. The equations for time in the moving frame. And so on. \n\nSometimes gamma is in the numerator. Sometimes gamma is in the denominator. Sometimes the gamma is squared. But it is in there a lot (you can look them up on wikipedia or any number of web sites).  \n\nThese equations have been verified over and over, in particle accelerators and other experiments. They also explain the Michelson-Morley experiment that provided evidence against the exisence of the ether. \n\nNow what what happens to gamma when v gets close to c?\n\nObviously, gamma gets very small. If you are dividing by gamma in the equations, you get huge numbers. So relativistic mass goes to infinity as v gets close to c, and time slows down and the object moving gets compressed front to back.\n\nWhat happens when v is exactly c? \n\nThen, time stands still, and the object's relativistic mass is infinite and it is infinitely thin. \n\nWhat happens when v is bigger than c?\n\nThen gamma becomes imaginary, and mass becomes complex and time becomes complex and so on. Obviously, a complex mass or a complex time have no meaning in our universe. \n\nThere are postulated objects called tachyons that go faster than c, but no one has ever reliably observed one. Distant galaxies can move away from us faster than c, but that is because no information is being transferred. Just like you can move a light source and make the spot of light very far away appear to move faster than c, but no information is being transferred. Relativity only restricts the speed of information transfer to be c or less. \n\nAre the equations of special relativity true? Well they fit the evidence we have. And until we have evidence that they do not fit, we use them.
661343
- They are the basics for all electrodynamical phenomenas (well, unless you go to high energy physics or go to the next "higher" level of abstraction, which would be electroweak interaction and quantum field theory).\n\n- They describe in an elegant way the physics over a HUGE amount of magnitudes. \n\n- They show the symmetry and also the assymmetry (no magnetic monopoles) between electric and magnetic fields.\n\n- They are Lorentz-invariant, which means that they hint to the special theory of relativity.\n\n- They explain why electromagnetic waves need no medium to propagate, which was a real puzzle at that time.\n\n- As they are partial differential equations they inspired phisicists and mathematicians to develop methods to develop more and more methods to solve these type of equations, which are now usefull in all kind of modern physics even in fields like many body quantum physics or high energy physics, that Maxwell never thought of, which closes the circle to what I mentioned first.\n\nIn short: They are a brilliant part of physics. (Although students hate them since the mathematics of partial differential equations is hard to learn ;) )
380806
Well, there are believed to be a class of unverified particles that surpass the speed of light called Tachyons.  If they move toward the object that created it then perhaps it could be true.  That's about the only way I could think to prove it since actually getting any object of study to surpass the speed of light would likely cause the big collapse and pull the entire universe on to one spot right were the object reached that speed and gain infinite mass as Einstein also theorized.\n\nOn the other hand, claiming anything as entirely impossible is foolish.  Science lives in absolutes and when thy get proven wrong, there always tons of frumpy old men in lab coats ready to restate that it was a theory though they called it a fact the day before.