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  • Hey, who turned out the stars?

  • Hello?

  • Seriously, where did they go?

  • Is this the end of the Universe?

  • Are we about to get all wiped out?

  • This is WHAT IF,

  • and here's what would happen

  • if all the stars in the Universe exploded

  • at the same time.

  • For every galaxy that's visible from Earth,

  • there are nine smaller ones that we can't see,

  • even with all the technology we've developed.

  • That's 90% of all space stuff

  • in the observable universe that we're missing out on.

  • We can't even see all the stars in the Milky Way.

  • Our home galaxy is just too cluttered with gas, dust,

  • smaller stars and one supermassive black hole.

  • All that makes it impossible to tell

  • how many stars there really are out there.

  • But whatever that number is, it sure has a lot of zeros in it.

  • Watching them explode all at once

  • might mean that the Earth is about to become

  • nothing more than dust in space.

  • But there's also a scenario

  • in which we could make it out alive.

  • All stars eventually exhaust their nuclear fuel and die.

  • Some of them depart modestly,

  • first swelling to the stage of a red giant

  • and then slowly cooling down over billions of years.

  • More massive stars explode into a blinding burst of light,

  • known as a supernova.

  • As stars go supernova,

  • they spit out a superheated shockwave in all directions,

  • along with a lot of radiation.

  • Supernovas exploding 30 light-years away from Earth,

  • could send us so much radiation

  • that it would start ripping apart our ozone layer.

  • Once the ozone layer was damaged enough

  • to allow just 10% more UV rays to hit the planet's surface,

  • nearly all marine life would be wiped out.

  • With two-thirds of the ozone layer gone,

  • people living in mid-latitude cities - from London to Melbourne -

  • would start getting severe sunburns.

  • Not even SPF 1000 would save your skin from that much radiation.

  • Some stars would take it a step further.

  • They'd collapse to form black holes.

  • From Earth, this would appear as a lot of bright flashes in the sky.

  • Because of the huge distances involved,

  • the explosions would happen in slow motion.

  • You could see one star exploding for over ten years

  • as the light from it continued to travel towards Earth.

  • You wouldn't hear any explosions.

  • Sound waves need molecules to travel through.

  • Since space is a vacuum, there'd be no volume,

  • only a really cool light show.

  • Technically, it's possible.

  • Our planet's surface would be wiped out and

  • all the oceans would boil away.

  • Any survivors would be forced underground,

  • watching out for further damage from exploding stars.

  • But at least life on Earth could have a chance.

  • Am I forgetting something?

  • Right, we'd be sharing our neighborhood with one exploding star.

  • If the Sun were to go supernova,

  • all life on Earth would definitely come to an end.

  • The surface of our planet would become 15 times hotter

  • than the surface of the Sun right now.

  • That alone would vaporize Earth within a few days.

  • Lucky for us, the Sun isn't massive enough to go supernova.

  • But if it exploded, it would send matter in all directions;

  • raining down on Earth 22 hours after the explosion.

  • I'm not going to lie to you.

  • It would be all bad in the end.

  • But then, exploding stars might form new stars

  • and new planets orbiting them.

  • It would be the beginning of a new Universe,

  • possibly with new habitable worlds and new life forms.

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

Hey, who turned out the stars?

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全ての星が同時に爆発したら? (What If All Stars Exploded at the Same Time?)

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    林宜悉 に公開 2021 年 01 月 14 日
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