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  • Hey Vsauce I'm Jake and if Star Wars were to have happened in our universe and truly

  • occurred a long time ago in a galaxy far, far away ... light from the actions in Star Wars

  • could be hitting Earth right now, or will some day. So if we pointed a telescope at

  • the right far away galaxy .... could we see Star Wars? Even if we choose the nearest spiral

  • galaxy to us, Andromeda, the requirements and results for resolving individual planets,

  • people or ewoks turns out ... to be almost as disappointing as the Phantom Menace.

  • To make out the flag on our moon from earth we would need a telescope that's 260meters.

  • If we wanted a clearer picture, one that would show us the stripes, if they were still

  • there, we would have to bump the size up to 6,850.

  • The biggest optical telescopes on Earth have mirrors around 10meters and the largest one

  • planned, the aptly named European Extremely Large Telescope, will be completed in 2022

  • and have a 39 meter mirror. Still a good deal smaller than you would need to see the flag

  • on the moon.

  • When you try and see small objects that are good distances away, especially when they

  • have less light, it becomes much more difficult to resolve. For example, here is the best

  • photo we have of Pluto, and this is a celestial body in our own solar system and relatively

  • close at 4.2 billion km.

  • So the reason we can take an amazing image of Andromeda, 2.5million light years away,

  • is because we are looking at an object that is an estimated 260,000 light years across

  • and contains a trillion stars. It has to do with the relative size to distance where Andromeda

  • would be .1 or 200,000 times greater than Pluto's.

  • If we wanted to be able to see a planet or satellite in a completely different galaxy

  • like Andromeda, you would need a pretty substantial telescope. To be able to get a glimpse at

  • the forest moon of Endor, more than double the size of Pluto we would only need a telescope

  • that was 6...wait for it... million 500 thousand kilometers in diameter. About the size of

  • 4.5 of our suns.

  • But we want to actually see what is happening on the planet. I mean, I want to look at an

  • Ewok with my own eye because they are adorable. To produce a fairly detailed image we would

  • need something gigantic, something 1.7 light years large. This telescope would surpasse

  • Voyager 1's current 18 billion km distance and would be larger than our solar system.

  • But here is when we run into a slight problem. Bad Astronomy has a great piece about pointing

  • Hubble at Earth and trying to get a photo. The resulting image would be blurry because

  • of how quickly it is orbiting. He likens it to "trying to take a picture from a moving

  • car: nearby objects will streak by, but far away objects appear to be moving slowly."

  • So even though Andromeda is spatially far away, it is magnified to such a degree that

  • we'd probably get a very blurry Ewok. The incredibly long exposure time the telescope

  • would need to collect enough photons to form an image wouldn't help either and whatever

  • image we were able to produce would have a blue hue since Andromeda is moving so quickly

  • towards Earth, at a rate of 300km a second, that the light is blueshifted.

  • Even light coming from people near you has to travel a distance. Since lightspeed is

  • finite, at arms length you're actually seeing a person 3 nanoseconds younger than they really

  • are. There is a constant flow of new, old light being spread out across the Universe

  • so who knows what we might be able to see next, maybe a galaxy far, far away.

  • And as always, thanks for watching.

Hey Vsauce I'm Jake and if Star Wars were to have happened in our universe and truly

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B1 中級

我們能看到《星球大戰》嗎? (Could We See Star Wars?)

  • 62 7
    Bing-Je 發佈於 2021 年 01 月 14 日
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