Special Relativity misconceptions
This is a work in progress.
DISCLAIMER: No mathematical proof or cited sources are given here, mostly because a) mathematical proofs are too advanced for the audience and b) finding articles that talk about 100 year old well-established physics is nigh impossible.
If you hold any of the following misconceptions, I strongly recommend finding an undergrad physics textbook and reading it, or just do us a favour and don't spread your wrong ideas.
Here's my list of what I think are the most prevalent and/or annoying public misconceptions about special relativity.
Most of these are, of course, the result of dumbed-down pop science programs on tv and the failure of our education system.
4) Scientists used to say that there was a "sound barrier" that could never be exceeded, but they were obviously wrong about that. Maybe they're wrong about the "light barrier".
Bullets exceeded the sound barrier in the 19th century. No actual scientist has ever, in the history of Enlightenment, ever said that nothing can go faster than sound.
Furthermore, Einstein didn't say the speed of light was a "barrier". He said it was the same for all observers. Everything else in SR follows from that postulate (among a couple of others). More on this later.
3) Accelerating to the speed of light makes your mass infinite.
Not mass. Momentum. Momentum approaches infinity from the perspective of a stationary observer.
Why not mass? Because in SR, mass is an invariant. An invariant is a quantity that never changes for any observer. The best known invariant is the speed of light, c.
3b) Accelerating to the speed of light requires infinite energy.
Nope. From the perspective of the stationary observer, your expended energy appears to increase asymptotically. However, ship-board energy consumption is linear.
2) E=mc^2 --> atomic bombs.
No. In reality, nuclear chemistry --> atomic bombs. Although it was Einstein that persuaded President FDR to create a nuclear program, and although in his letter to the president he probably did reference the equation E=mc^2, it was only meant as a sort of ex-post-facto explanation for how so much energy can come from such a small bomb. In fact, E=mc^2 would not be at all helpful for anyone trying to build a bomb.
1) You can't go faster than the speed of light.
Actually, you can. There are just a few provisos.
First, no one will ever observe you going faster than light. To all observers, even the
stationary ones, you will only appear to be going, at best, slightly less than c.
Second, for the person actually in the spaceship, they must be content to measure their speed by counting landmarks as they pass by, like stars. If you see 3 stars go by in a year of travel, and you know that stars are (sans length contraction) about 5 light years apart, then you're EFFECTIVELY* going 15c.
*I say effectively because you're not actually surpassing c, technically speaking. But if you're willing to ignore time dilation, there isn't a difference as far as you're concerned.
Third, time dilation. If you go home, everyone you ever knew is long since dead. Of course, if your goal was to travel into the distant future, then this is a plus!
Fourth, more time dilation. Whatever destination you're trying to reach will ALSO appear to pass into the future as you approach it. So, for example, if you want to go to Alpha Centauri because in your super powerful telescope you see a naked Navi waving at you, too bad. By the time you arrive, she will have moved on.
But, all that being said, suppose you have a ship that can accelerate at 1g (relative to
itself) for many years at a time. At 1g acceleration, you can go anywhere in the universe in a single human lifetime, shipboard.
