Can You Go the Speed of Light?

Einstein's classic thought experiment involves sitting on a train travelling at the speed of light. If you hold a mirror in front of your face, will you see your reflection in a mirror? How could light from your face reach the mirror if the mirror is travelling away from you? But it would be a pretty spooky train if you couldn't see your reflection so Einstein felt this solution wasn't realistic. On the other hand if you could see your reflection, it would mean light was travelling at the speed of light inside the train. But that meant the same light observed from outside the train would be going twice the speed of light. This again seems inconsistent. So Einstein resolved that you must see your reflection but that light must travel at the same speed inside and outside the train. The only way this is possible is if space and time are perceived differently by observers inside and outside the train.

[sprokkelmof]

I can not wrap my head around how genious some people can possibly be. Take Einstein, he lived 100 years ago, had no computer to calculate or simulate anything, and yet he comes up with and finds evidence for abstract theories that even today still hold true. Hats of to scientists.

[UndoneFakeJesu]

The neutrino thing didn't hold up. It was later confirmed to be a faulty result.

[dragonmateX]

"this is city rail, we are lucky to be moving at all" ahhh Sydney jokes

[osotanuki]

Traveling at the speed of light:
Size=0
Mass=infinity
Well, Einstein really knows how to mess with your brain

[ButoPulseGames]

"Thought is faster than light"
Derek: "...." XD

[jukappa]

I don't consider myself exceptionally smart, but I always start to reconsider when he does his interviews.

[samarium]

I just love how Einstein was like "hmmm... space and time are making it real hard to answer this one question. I guess I'll have to change our fundamental understanding of the universe and time and blow everyone's mind..."

[DarkMetsuo]

A limerick: There once was a girl named Bright, whose speed was much faster than light. She left one day in a relative way and returned on a previous night.

[garydunken]

What would it be like to travel at the speed of light?
0:21 I imagine everything would get intense... yeah, nice one dude.

[algorithm]

"Our length would become zero, our time would stop passing, and our mass would become infinite."

Our mass is already infinite here in America.

[anshusaxena]

I have always been amazed by the relation of time and relativity and how it affects our lives..notice it or not. Sir this is one of the BEST videos of your channel.

[bawshawg]

I love his man-on-the-street question segments. I'm amazed at how little people know about basic science, or how way off their perceptions are.

[deliciousbutter]

I love it when you talk to other people and they say ridiculous things

[Arpansahaofficial]

I've never come across such a beautiful and legible explanation during my college days. thanks Ve..

[noahwelikson]

Thought is faster than light: facepalm

[UltrasabersVideos]

When it comes to space travel, there is no need to go the speed of light. In the far future, we'll fold space to traverse long distances. 

[kaylor]

"Uhhh.... thought?"

Took her that long to give an answer; I guess thought isn't as quick as the speed of light lol

[TomWrightMusician]

Wonderful video, thanks! This question has been bugging me for a while!!

[ourworldrhythm]

The woman was so dumb
"Yeah the speed of thought is faster" LOL

[_____________________]

I have a question that i never found an answer for...

Why cant light travel faster than c?

Photons do not have mass, so why stop at ~299, 700km/s?