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  • The Earth may not be our home forever.

  • Eventually, we may have to leave.

  • What if instead of finding a potentially habitable exoplanet

  • light-years away,

  • we stayed in our Solar System

  • and built a habitat so enormous

  • we could never overpopulate it?

  • This is WHAT IF,

  • and here's what would happen

  • if we built a ringworld in space.

  • Imagine you lived on a ring

  • with a radius of 150 million km (93 million mi)

  • encircling the Sun.

  • A gigantic artificial world

  • with its own gravity,

  • ecosystem and atmosphere.

  • Big enough for trillions of humans to call home.

  • You'd live on an enormous landmass on the inner side of the ring.

  • The outer shell would protect you and all those trillions of people

  • from the hazards of outer space.

  • Problem is, assembling such a thing -

  • suspended out in the Solar System -

  • wouldn't be easy.

  • You couldn't just pull the Earth apart

  • and have an army of robots.

  • reassemble it into a ringworld.

  • Among the many problems you'd run into,

  • your first would be finding the material.

  • The International Space Station roaming the Earth's lower orbit right now

  • weighs about 420 tons.

  • Something like a ringworld

  • would tip the scales at no less than a million tons.

  • Where would we find all this material?

  • I know some places.

  • The Kuiper Belt beyond the orbit of Neptune would do just fine.

  • This ring of icy bodies stretches out for almost 3 billion km (1.9 billion mi).

  • Some astronomers think the Kuiper Belt

  • would have enough material for this project, but...

  • it's hard to tell exactly how much we'd need

  • to construct a thing like this.

  • We might have to sacrifice all the planets,

  • moons and asteroids in the Solar System.

  • Our ringworld and the Sun would be the only things left.

  • If we could manage to gather and transport all the material available,

  • then construction would begin.

  • It would take a lot of physical labor,

  • an army of robots and maybe hundreds of generations

  • to realize that our structure was not stable enough.

  • Because the megastructure would turn out so enormous,

  • it would break any known molecular bonds.

  • We'd have to find a way to make use of one of the fundamental forces of nature -

  • the strong nuclear force.

  • Of all forces, it's the grippiest.

  • It bonds material on the scale of atomic nucleus

  • so that nothing can break it apart.

  • Or maybe we'd come up with a new super-strong material altogether.

  • But until we figure that out,

  • every interstellar body passing through our Solar System

  • would be a threat to our megastructure.

  • The next thing we'd have to worry about is gravity.

  • That part is pretty easy -

  • we'd just have to spin the ringworld at nearly 2,000,000 km/h (1,200,000 mi/h).

  • I know, that's really fast.

  • We'd have to build up the speed over time.

  • Luckily, maintaining it in the frictionless environment of space

  • wouldn't be too hard.

  • Such rotation would generate centrifugal force,

  • and that, in turn, would create an artificial gravity

  • equal to the one we have here on Earth.

  • With gravity solved, we'd bring in the atmosphere

  • and start populating the ringworld.

  • For the inhabitants of the megastructure, it would always be daytime.

  • Unless we could create a day and night cycle

  • with extra panels inside the ring.

  • But for all the epicness of the world we just created,

  • it wouldn't be stable.

  • A single asteroid strike could cause the structure to drift closer to the Sun.

  • A hole punched through the ring

  • could let all our atmosphere out.

  • And a massive solar storm?

  • Don't even get me started on that one.

  • One failure inside the ring

  • could doom the entire structure together with its inhabitants.

  • It's just too risky to build it around the Sun.

  • We might have better luck

  • with a huge ring space station in the Earth's orbit.

  • But that's a story for another WHAT IF.

The Earth may not be our home forever.

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B1 中級

宇宙にリングワールドを作ったら? (What If We Built A Ringworld In Space?)

  • 3 1
    林宜悉 に公開 2021 年 01 月 14 日
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