Placeholder Image

字幕表 動画を再生する

  • If you could teleport the Earth

  • to any place in the Universe,

  • what would you want to look at

  • in the night sky?

  • The bright explosion of a supernova?

  • A black hole passing over your house?

  • How about a nebula?

  • This is WHAT IF,

  • and here's what would happen

  • if we lived inside of a nebula.

  • What is a nebula anyway?

  • A nebula is a giant cloud of dust and gas

  • in interstellar space.

  • They are vast,

  • sometimes taking up hundreds of light-years of space.

  • But with all that size, they aren't massive.

  • A nebula the diameter of the Earth

  • would only have a mass of a few kilograms.

  • That's because nebulae aren't very dense.

  • And that's why, if we lived inside one,

  • it wouldn't look anything like what you might expect.

  • Some 1,344 light years away from Earth,

  • is the Orion Nebula -

  • the brightest nebula in our sky.

  • It's 24 light-years across,

  • and has a mass equivalent to 2,000 Suns.

  • If the Earth was formed inside it,

  • all you'd see in the night sky would be this.

  • Not impressed?

  • I know, I wasn't either.

  • It turns out it's not that easy to see a nebula

  • when you look at the night sky.

  • To your eye, most galaxies in the Universe

  • don't look anything like this.

  • More like this.

  • And most nebulae are invisible altogether.

  • Your eyes aren't sensitive to the kind of light a nebula produces.

  • But look at the image taken by the Hubble Space Telescope,

  • and you'll see a beautiful gas cloud.

  • That doesn't mean these beautiful images of space are fake.

  • Their colors just represent the lightwaves

  • that your eyes aren't able to detect.

  • So, if you had the Hubble Telescope,

  • would you be able to see a nebula if you lived in one?

  • Sorry to disappoint you again, but no.

  • Nebulae are pretty only when they are hundreds of light-years away.

  • They look thick and cloudy only because

  • you see the structures of light-years in thickness.

  • Once you're close to them, their light spreads out so much

  • that you can't see them.

  • You could fly your spaceship right into the nebula

  • and never even know it.

  • If the Earth were inside a nebula,

  • the only effect you'd see would be brighter Auroras.

  • Unless the solar wind blew all the nebular particles

  • far away from the planet.

  • How do we know we are not living inside a nebula right now?

  • Simple.

  • After gathering the data on our own Sun,

  • we can calculate the expected brightness of the neighboring stars.

  • If we did live inside a nebula,

  • we'd notice that our star was much brighter compared to others.

  • The nebula would be dimming the light coming in from outside of it.

  • But don't be sad.

  • We can't teleport the Earth, yet.

  • But we may be able to travel to distant exoplanets

  • that experience incredible light shows in the night sky.

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

If you could teleport the Earth


動画の操作 ここで「動画」の調整と「字幕」の表示を設定することができます

B1 中級

もし地球が星雲の中にあったら? (What If Earth Was Inside of a Nebula?)

  • 2 0
    林宜悉 に公開 2021 年 01 月 14 日