Answer: What would happen if you could travel faster than the speed of light?

David Gross, Nobel Laureate in Physics 2004, has answered a selection of your video and text questions from YouTube and Facebook, including his explanation of how we detect neutrinos, his thoughts about the LHC and information about what books influenced his career choices.
Thanks to everyone for your participation.

[blazedgamingkr]

Actually you can travel faster than light and still not break relativity. Unfortunately we can't bend and fold space yet. But to truly answer her question, I'm going to make a few assumptions. First we will assume you do have the infinite energy required and second we will assume that you have an indestructible ship because at those speeds even small hydrogen particles that to exist in the void of space (space isn't a true vacuum because it does have particles floating in it) will be hitting your ship at the speed of light and will rip the ship apart. Now, after those assumptions, let's go to light speed. At first you will notice that your vision will start to tunnel. As you get closer to the the speed of light everything will start to shift colors due to the Doppler effect. When you do reach the speed of light, time dilation will be massive. So much so that time itself might actually stop. Which gets into your question. If you were to break the light barrier, so to speak, your physical form will become completely invisible as you are now traveling faster than the light reflecting off you. In other words it will look like you are farther back than you really are. Your "afterimage" for lack of a better term, would still only be traveling the speed of light because that's what people see. They won't really be able to "see" you traveling faster than light. Some people believe you will go backwards in time, but no one can really say for sure as your question can't really be answered until we can do it. And I apologize for his very redirected answer. As he answered with "you can't go faster than light" which is the cut and dry of it. But we will never achieve it if people just throw their hands up and say "it's not possible". How can we encourage the younger generation if we keep telling them you can't do it. I mean if you want to go super deep into it, there are a few ideas in quantum physics that could allow for an object with Mass to travel faster than light. Although it would take every particle in your body to, essentially, quantum tunnel to a different location instantaneously. It relies heavily on probability and that probability is so low that you could stand in one location for the entire age of the universe and it still not occur. But to simply answer the question with, it's not possible, is lazy. I mean, go listen to Kennedy's speech on going to the Moon. We did it not because it was easy, but because it is hard. And just because we haven't found a way to truly travel faster than light in a vacuum doesn't mean we won't. Sorry for the long winded comment but I think your answer was, well as I put earlier, lazy.

[arthurlewis]

He's never going to travel at the speed of light with that attitude.

[magesmathew]

She didn't ask if it was possible..

the question was what if you did

[galpal]

His answer reminds me of the poem that goes like this: there once was a lady named bright who could travel far faster than light. She set out one day, in a relative way, and came back that previous night.

[MartinChibanda]

If one could travel at the speed of light (in a thought experiment because we cannot travel at that speed), then very strange things would happen. One of the more exciting things is that time would appear to stand still for the traveler. For example, travelling to the nearest star system would feel like you reached there instantly while everyone back on earth would miss you for four years within your perception of that instant.

[DaBrute]

dammit she didn't ask if it was possible, but what would happen it you did

[suvomitra]

Literally this is a heartbreaking answer

[nobitanobi]

"Special relativity provides a double opportunity for time travel. If you travel at a sizable fraction of the speed of light, time for you slows with respect to the outside world. In effect, you move forward in time. And if you can travel faster than light, you will have a means to move backward in time."

An excerpt from a book I'm currently reading, How To Build a Time Machine: The Real Science of Time Travel by Brian Clegg.

[PaladinswordSaurfang]

Gravity doesn't accelerate particles faster than light. In gravitational fields, time slows down, your mass increases etc. Basically everything that happens whne you approach the speed of light happens when you are in strong gravitational fields. Furthermore, gravity can bend the path of light towards it, but it cannot speed it up.

[ruchpat]

Thank you Nobel Prize for posting this video.

[mamidalavijaya]

you gave the right answer sir.I respect you.That's what my chemistry sir has told me.

[rgavlog]

the question was WHAT WOULD HAPPEN IF YOU TRAVEL FASTER THAN THE SPEED OF LIGHT?
just answer it

[kahvue]

I liked the video solely to be able to easily come back to the comments for the real answer

[andresmit]

You did not at all answer the question my good sir.

[hansschetselaar]

Interesting but my question is now: how did particles without a mass reach the speed of light? And how did the em radiation that has no mass, only waves, reach the speed of light?

[Sereomontis]

The question was "what would happen if you could travel faster than light", not "why can't we travel faster than light".
I think practically everyone who has even a basic understanding of physics know you can't travel faster than light. I came here looking for the hypothetical theoretical scenarios about what might occur if travel at that kind of velocity were possible.

[johnmukaru]

if u traveled at the speed of light there is no time thus you wouldn't find time to stop...so eternally moving.

[wierdsmabob]

Since God is infinite he could also travel at an infinite speed since he has no body mass to make that impossible. Thus the universe could be created within an instant and the light could also be sped up to an infinite speed to make it appear instantly on earth.

[Eldon]

If something traveled as or faster than the speed of light, it would be invisible. That's why we can't see light.

[travis]

If you traveled at the speed of light, you would logically go backwards in time. Imagine somewhere far far away (about the distance light travels and then some), now at this place, there is a extraterrestrial or a human (it doesnt really matter). Now say they are looking through a massivly enhanced telescope and could see earth on ground level. What would they see? They would see past events. Now how far back would have to be determined by the distance they are from earth, because the farther back you go, the harder it is for light to travel. This is why, i believe at least, that of you moved faster, then you would be turning time back because your moving so fast that the light cant move as quick as it does. I have no idea if i made any sense, as im only a kid (14) and cant clearly put my thoughts into the correct words, but please leave your opinions (critical or not) or comments on my theorem, as this topic really intrigues me