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  • There are still lots of things about space

  • that we may never be able to answer,

  • like is time travel possible?

  • Or are aliens living somewhere else in the Milky Way?

  • But there is one thing I believe about space:

  • Space is trying to kill me.

  • Space isn't out to get me personally.

  • It's also trying to kill you and everybody else.

  • Think about it.

  • Space doesn't naturally have what we need to survive

  • when we travel there:

  • no air,

  • it's too hot

  • or too cold,

  • no ozone to protect us from those nasty UV rays, either.

  • This all sounds bad,

  • but what can space really do to me

  • if I stay on Earth?

  • What we need to understand is that objects in space

  • can cause people to think their days are numbered,

  • even when there are events on Earth

  • that can hurt or kill us

  • before something from space does.

  • So, what are the odds that one of these objects

  • will really affect Earth

  • and you

  • and me

  • in our lifetime?

  • Well, we can take what we know about the universe

  • to try and figure that out.

  • You might have heard stories

  • about asteroids hitting the Earth.

  • That would be pretty bad.

  • Scientists think asteroids might have killed off

  • most of the dinosaurs.

  • Sounds like something we should worry about, right?

  • Well, astronomers can now watch asteroids in space

  • and see them coming using complex computer models

  • to predict the deadly rock's path.

  • For a while, the reported odds

  • that asteroid Apophis would strike Earth in 2036

  • were once 1 in 625.

  • But, after updating their data,

  • astronomers now say the chances are extremely low.

  • Okay, what about the sun?

  • Hollywood movies like to pick on our sun

  • by showing Earth destroyed by solar flares

  • or the sun dying out,

  • which would cause Earth to freeze.

  • Astronomers predict our sun contains enough gas

  • to make energy for another 3 to 5 billion years.

  • So, in 3 to 5 billion years,

  • if people still exist on Earth,

  • they'll have to deal with that.

  • But today, well, we're safe.

  • Sometimes the sun does shoot flares at Earth,

  • but the magnetic fields surrounding our planet

  • blocks most of that radiation.

  • The radiation that does get through

  • creates things like the Aurora Borealis.

  • Gigantic solar flares can mess with our satellites

  • and electrical equipment,

  • but the chances of it killing you are pretty slim.

  • Okay, what about that supermassive black hole

  • in the middle of our galaxy?

  • What happens to Earth,

  • and us,

  • when it pulls us in?

  • After all, it is supermassive.

  • Nope, not going to happen.

  • That's one big object that can't bother us.

  • How can we be so sure?

  • Our solar system is on the edge of the Milky Way

  • while the nearest supermassive black hole

  • is about 26,000 light years from Earth.

  • That means we aren't on that black hole's menu.

  • So, you still think space objects are trying to kill you

  • even after what I've told you so far?

  • I think I've even convinced myself

  • that odds are really good

  • that space and the objects up there

  • won't kill me after all.

  • But I'll probably keep looking up

  • just to make sure nothing is headed my way.

There are still lots of things about space

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B1 TED-Ed space earth supermassive sun black hole

【TED-Ed】Is space trying to kill us? - Ron Shaneyfelt

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    VoiceTube posted on 2013/07/05
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