This video shows how long it takes for light to travel from Earth to Mars and back again

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It truly is mind-bending just how slow the universal speed limit is in relation to how large the universe is. At least relativity makes the trip short from the refrence point of the traveler.


I can’t drive 55!


You can almost say “I saw it coming.”


That all depends on how fast you can accelerate your spaceship. Having a high top speed is fine but if it takes you a century to get there you’ll still die of old age.


Let’s face it. Einstein is holding us back.


Plus by the time you get back the damn dirty apes are running everything.


I was kinda hoping something cool happened when the light blob made it back to earth.


Netflix is gonna suck on Mars


This video does an excellent job of illustrating the fact that my attention span is much less than 3min 02sec.

Did I miss a surprise twist at the end?


This may be more your speed :wink:


It is.

But now I can’t get the joysticks to move the Earth or the Moon. Is this game not mac compatible?


Here’s a photon’s view of its real-time journey from the Sun to around Jupiter: – with soundtrack by Steve Reich.

Turns out that the speed of light is pretty durn slow.

Also – FULL SCREEN and SOUND ON. This vid is gorgeous.


Great film. Kind of slow.

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Worst. Game. Of. Pong. EVER!


Great illustration of the scales involved. Reminiscent of Ray and Charles Eames Powers of Ten. I have a bit of a contention with this form of framing of the topic though. It’s normal in science popularization to talk about it like light is traversing space at some finite rate, not saying that’s wrong - but putting it like that is a little misleading and risks missing a more profound aspect of the thing.

The way it’s framed in this video, there is an implicit/unacknowledged insertion of an external reference frame, (you, the viewer - for whom there is sort of stable concept of the “present”). But wait! One of the consequences of what Einstein revealed with his discovery of Relativity is that at larger scales our notion of a coherent moment doesn’t work like it does at the size of things that we’re used to. What we now know is that nowhere is there an “outside reference frame”, at larger distances there is no “simultaneous”. So when we show light moving at a finite rate it’s suggesting a state that A) relativity says is not only impossible - but logically incoherent given how we know things actually behave, and B) misses an opportunity to talk about the really wild stuff that relativity shows - basically that C (light speed), is the spatially outward propagation of what we conceive of as “now” given our present location, and that that now doesn’t have meaning from some other location without consideration of their specific distance. Sames goes for statements about light from stars being “old”, as though it was always in the referenced reference frame - no it “got here” just now!

edit (for spelling and …) :
TL/DR - the light does get there instantly, it’s just that for larger distances instantly takes “a while”.


If (big if) you can accelerate at a constant 1g, you’ll reach the speed of light in roughly a year (shipboard time).

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I think your second paragraph nicely shows why it’s normal… :slight_smile:

You will get very close to the speed of light in a year. You will never reach it, and you could keep increasing tau indefinitely by getting closer and closer to it, if you had enough energy.

I think using natural units illustrates part of this. The speed of light is 1 planck distance per planck time, meaning that, for every minimum unit of time, light moves one minimum unit of distance.

True enough but it would take something like a fusion reactor to make that happen. I was thinking along the lines of a light sail, something that might be possible today, maybe.

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