Faster than infinity
Posted by Jeff Id on September 8, 2010
Ok, so this post is not about climate at all, I’m not sure why I’m writing it except that the concepts are fun, it’s controversial amongst those who haven’t spent their lives in science, and it’s well known.
You can’t travel at the speed of light. I’m not saying that other things can’t because the structure of our universe dictates that some things MUST travel at the speed of light. But objects made of clumped energy (matter) and YOU cannot travel at the speed of light.
The concept is disastrously confusing because of the way it is worded. I’ve spent a lot of time at this blog trying to make science simpler so the public can get what is being done. When relativity is discussed in science classes, people ask things like – why not, is there a wall. I know some very smart people who have gone as far as denying the effect exists, simply on the basis that it sounds impossible. Physicists answer by equation in every class I’ve ever taken. They say, naw your mass increases so you can’t accelerate.
While that is completely true, what is missing in that answer is the perspective of the person trying to accelerate. From earth’s perspective if you are zooming away at 1 km/hr slower than the speed of light, you can accelerate faster and faster at a thousand g’s for a billion years and will never reach or cross the speed of light. From your own perspective (visual distortions ignored), Earth starts out receding at 1km/hr. Light inside the ship seems the same as always. If you measure the distance to a star and it’s going to take 5 years to get there, you can just accelerate and cut the time to 2.5. It takes no more effort to double your perceived speed than it would if you were on the surface of the Earth. Odd things happen while you’re doing it, like the distance to the star shortens instead of the expected result, but you get to keep on accelerating all you want.
Now say you want to go to Andromeda galaxy, which is about 200 million light years from here. It takes 200 million years for light to arrive – a long way. What if you wanted to go their in your lifetime, is it possible?
The answer is yes, of course it’s framed in physics that time slows, distance compresses, mass increases, but from the perspective of the spaceship, if you want to go faster, you always can. Always. You can even go so fast as to cross the entire universe in a second.
What you can’t do though, is go as fast as light.
- – wiki Lorentz factor
The Lorentz factor is used in the relativistic forms of classical physics equations. When v (velocity) = c (speed of light) the denominator (bottom) becomes zero and the equation becomes undefined. What is interesting is that as v comes closer to c, γ approaches infinity.
Remember though, math is a representation of physics, not the other way around. Mass increases? Distance shortens? and Time slows? I’ve been around for a while, in my opinion these concepts are fairly strange. It speaks more to the fact that our understanding of what is mass, distance, and time are, is limited than anything else.
I’m too lazy to look up all the details for people not interested enough to do it themselves. (grizzled blogger) but distance, mass, and time approach wild limits as you get closer to light speed. Time goes to zero (frozen in time), distance goes to zero in the direction of travel (you become more 2 dimensional), mass goes to infinity. Below you can see that as gamma approaches infinity, time approaches zero.
T’ = T(1 – (v/c)2)1/2 = T/γ,
Kinda neat, it’s also interesting to note that there is no need to go faster than the speed of light to travel to a star or even a far away galaxy in your lifetime. You can already do it with enough energy. Those who stay behind will age though, equally to the distance you travel in light years. Time travel to the future, is perfectly reasonable and has been demonstrated by experiment. It’s just not very much time travel until you cover a lot of distance and don’t expect to go back.
Oddly, nothing about the equations are undefined for going over the speed of light. They work perfectly, however crossing from below to above is a bit tricky.
So sorry for the strange post, but the point is that light is infinitely fast. It crosses the universe without a single click in time. Faster than light is faster than infinity. Where we monkeyfaces go wrong is in our understanding of time, distance, mass and by combination — velocity.
So why do you want to go faster than infinity anyway?