>>19375788
>>19376644
ITT someone pretends they have a physics degree.
Alright, anon. Pretend you've just left the Hooker Planet on a spaceship. From the point of view of the kids you've left behind, you're leaving at some velocity v. From your point of view, though, the *planet* is moving away from *you* at velocity -v (same speed, opposite direction). Which one of you is right? To the best of our understanding, you're both right: there's no universal anchor that defines "really at rest". This is the crux of special relativity: all inertial reference frames (not experiencing any acceleration) are equal, and they all experience the same laws of physics. (Dealing with non-inertial reference frames - ones experiencing acceleration, including gravity - is the domain of general relativity.)
Let's pretend that it's well-defined to travel at the speed of light or faster. Now, your spaceship speeds up until it settles down at exactly the speed of light, and you get bored so you conduct the following experiment: you try to measure the speed of light by aiming a laser pointer at the wall opposite your direction of travel and having a machine tell you how long it takes for the beam to appear on the wall after you turn it on. Well, you're in an inertial frame of reference, so all of the laws of physics apply to you, including the speed of light. If the wall is 3m away from you, the machine measures about a time interval of about 10^-8 seconds.