The way things stand now, if you have mass, you can't go at light speed. E = mc2 dictates that you need a certain amount of Energy (E) for something of mass (m) to go the speed of light (c2). The problem is that mass dilation dicatetes that the faster you go, the more mass you gain. So m goes up exponentially, meaning E goes up more than exponentially and, no matter how much energy you have, you're always trying to catch up to the amount of energy you need because of your increased mass.
The reason why a photon (which is the building block of light and the carrier of electromagnetism) goes at the speed of light is because a photon has no rest mass. Its mass is 0, so the energy required to make it go the speed of light is also 0.
There are theoretical particles that go faster than light. The most well known is the tachyon and scientists theorize that it can go faster than light because it has a negative mass. Nobody knows for sure, though: we see because light bounces off things, but if something is going faster than light, than light can't bounce off it in any predictable fashion, so chances of seeing a photon that happens to bounce off it while we're watching are almost nill. If we can't see something, we can't test it. And, in science, if we can't test it, it doesn't exist. Therefore tachyons, for now, are nonexistent/theoretical particles. And scientists say, no, they probably don't exist.
Incidentally, light isn't the only thing that goes at lightspeed. Radiowaves, gamma radiation (which are both photons of different frequencies than light), and gravitons (another theoretical particle) travel at lightspeed. And, according to the Tick, lint travels faster than light.
But people do go forward in time all the time, just not how you think of it. What people think of when they mean time travel is that you skip over a period of time. But originally, in Time Machine (which, I think, is the first story involving time travel), what the Time Traveller did was fast forward time, not skip it. Look up soemthing called time dilation. The bottom line here is that, the faster you go, the faster time accelerates for everyone else. Technically if you drive at any speed, you've accelerated everyone else's time by fractions of a second. Some astronauts have actually "travelled" a few seconds into the future. The problem is that, going something like 40 mph is a minuscule fraction of the speed of light (186,000 miles per second), so the effects aren't even measurable by our computers. But one day, maybe. The bottom line here is, the faster you go through space, the slower you go through time. Check out time dilation. It's incredibly wonky. When people say "truth is stranger than fiction," they must be talking about this.
What you really want to do if you want to travel through time is get yourself a gravity well. Gravity warps the fabric of time (which is, yes, an actual measurable concept, just like any of the three spatial dimensions, but perhaps not a "thing"). Problem is you need an incredible amount of gravity. But time can be manipulated, and everything that has mass technically manipulates it since everything that has mass has a gravity field.
SlyTF1 wrote:Time itself is faster than the speed of light. If there was no time, then light wouldnt travel at any speed.
If you can equate it this way, time technically goes AT the speed of light. But that's probably a discussion for another message, since this one is probably getting into the TLDNR category.