I’ve been thinking about gravity and time. I get that percieved time changes depending on which planet you’re on, more gravity= faster time is. I also understand that the person on that planet will not notice any difference.
For an example, ben teleports to a super big planet, and hangs out there for 5 hours, teleports back to earth and boom, its been 5 months in earth time.
But, if we somehome could, with a telescope, see ben on that big planet, would we percieve him as going slomo, or almost not moving?
In: 136
So it’s actually the reverse, more gravity slows the passage of time relative to an outside observer. This real life phenomenon is actually what inspired part of the movie Interstellar, where astronauts visited Miller’s planet which orbited just beyond the event horizon of a supermassive blackhole. The gravity of the black hole is immense and so this translated into a time difference of 7 Earth years for every 1 hour on Miller’s planet. The astronauts ended up stranded on Miller’s planet for several hours (from their perspective) but when they returned to their mothership over 20 years of Earth time had passed. The crazy part is that this phenomenon is actually a real, experimentally verified thing. Theoretically if such a planet did exist you could take a trip there and return younger then your own children.
To the outside observer time would be ticking considerably slower for the astronauts (or Ben in your example). They would appear to be moving very slowly and would appear dark red (if they’re even visible at all). This is because of a phenomenon know as [gravitational redshift](https://en.m.wikipedia.org/wiki/Gravitational_redshift). Light is a wave, and the color you see corresponds to it’s wavelength when it reaches your eye – with red being low frequency (long wavelengths stretched apart) and blue being high frequency (tiny wavelengths squished together). Because of time dilation the time you receive each wave of light from the astronauts is longer, which effectively stretches the wavelength like an accordion and turns it red from your perspective.
Another way to think about gravitational redshift is to imagine someone clapping their hands. The slower they clap their hands (lower frequency) the redder the light and the faster they clap their hands (higher frequency) the bluer the light. If the astronauts clap their hands once per second (as they measure it) then because of gravitational time dilation the outside observer sees the time it takes to finish one clap taking considerably longer, so the astronauts light appears more red to the outside observer.
Latest Answers