If nothing can be faster than the speed of light, why don’t we make the speed of light faster? Hey there speedsters, Julian here for DNews. Unless you’re a certain comic book character who keeps messing up the timeline — Barry — you can’t go faster than the speed of light. It’s the top, the be all end all of speed, and nothing can go faster than it, including itself, and it’s always been that way, period. End of story. OR IS IT??? That’s what theoretical physicists at the Imperial College of London are trying to figure out. Decades ago, they proposed that the speed of light may have been faster in the early days of the universe. They weren’t able to test their prediction because instruments weren’t sensitive enough to precisely measure the cosmic microwave background radiation, a.k.a. the light leftover from the Big Bang. Now you may be wondering, why would they even think the speed of light might have been different at any point? Well, all across the universe, the cosmic background radiation seems to be about the same temperature no matter where you look, and this is puzzling.
For that to be true, photons across the universe must have interacted and settled into an equilibrium, but given the size of the universe and the speed of light, that’s just not possible. The most commonly accepted way to get around this so called “Horizon problem” is known as the Inflation Theory. This idea states that when the universe was just 10-35 seconds old –so a decimal point with 34 zeroes and then a 1 seconds–, it expanded by a factor of 1026 –which is an insanely bigly number– in a tiny fraction of a second, before chilling out and expanding at the much less ludicrous speed we see today.
That means before the universe stretched out at the speed we see today: the photons could have been in equilibrium. The Inflation Theory is so popular because it solves the Horizon Problem along with other issues the Big Bang Theory presents. But there’s another way around this problem… what if the speed of light isn’t constant? Why not have light just… move faster? That’s what these scientists are trying to figure out, and it would challenge a huge precedent. See one of Einstein’s biggest breakthroughs came with the discovery that light is always traveling at a certain speed, specifically 299,792,458 m/s. I don’t care who you are, where you’re from, what you did, as long as you measure light, that’ll be the speed. If you’re driving at 100 miles an hour and turn on your headlights, the photons coming out of them don’t go 100 miles an hour faster.
Einstein realized if the speed of light is constant, then space and time could be flexible parts of the equation and the theory of Special Relativity was born. And this constant speed thing seems to hold up no matter what we do. Some of you may have seen stories about scientists slowing down light. But they’re not. not really. When light goes through a medium like water or a pane of glass — which is probably how you’ve seen light “slowed down” the photons themselves aren’t traveling more slowly, they’re just bouncing off the atoms and taking a less direct path. It’s why when they leave the medium light travels quickly again, instead of staying at its slower speed.
This illustrates why people usually specify that there’s nothing faster than the speed of light in a vacuum. So right now, the speed of light seems pretty darn fixed. But so does the rate the universe is expanding. billion years ago, when the universe was brand new and the rules were like the wild west of physics, maybe one of those things wasn’t so steady. When our instruments are good enough we’ll test this new idea and if it’s wrong, we’ll stick with cosmic inflation. If it’s accurate, well, we’re going to have a lot of rethinking to do. If cosmic inflation theory IS true, then there could be parallel universes. To learn how and see me IN TRIPLICATE, check out this awesome 360 video we made on the topic.
So which makes more sense to you, insane inflation or an upped speed of light? You can let us know in the comments, subscribe for more and we’ll see you next time on DNews..