/sci/ - Science & Math

>>4297928

>An objection that is sometimes raised against the concept of time machines in science fiction is that they ignore the motion of the Earth between the date the time machine departs and the date it returns. The idea that a traveler can go into a machine that sends him or her to 1865 and step out into the exact same spot on Earth might be said to ignore the issue that Earth is moving through space around the Sun, which is moving in the galaxy, and so on, so that advocates of this argument imagine that "realistically" the time machine should actually reappear in space far away from the Earth's position at that date. However, the theory of relativity rejects the idea of absolute time and space; in relativity there can be no universal truth about the spatial distance between events which occur at different times[82] (such as an event on Earth today and an event on Earth in 1865), and thus no objective truth about which point in space at one time is at the "same position" that the Earth was at another time. In the theory of special relativity, which deals with situations where gravity is negligible, the laws of physics work the same way in every inertial frame of reference and therefore no frame's perspective is physically better than any other frame's, and different frames disagree about whether two events at different times happened at the "same position" or "different positions". In the theory of general relativity, which incorporates the effects of gravity, all coordinate systems are on equal footing because of a feature known as "diffeomorphism invariance".[83]

Get Wikipedia'd son.

>>4286624

Oh you believe in free will.

protip: there's no ghost in the machine. When you're dehydrated, the lack of water kickstarts a cascading neurological response which releases hormones and chemicals that effect nerve pathways that make you move your body toward water and drink it. You thinking "I'm thirsty" is a result of this, not its cause. They happen at the same time.

Also:
>popsci, but still really cool

http://www.youtube.com/watch?v=N6S9OidmNZM

>and here's the meat and potatoes:

http://rifters.com/real/articles/NatureNeuroScience_Soon_et_al.pdf