What If We Moved Earth?

WHAT IF

12/11/2023

What will happen to us when the Sun turns into a red giant?

Transcript

00:00 Five billion years from now,

00:06 the Sun will expand and become a red giant.

00:10 And the Earth might just be in the way.

00:14 If humans were still around then,

00:16 would we leave the Earth?

00:18 Or would we move it?

00:21 This is WHAT IF,

00:23 and here's what would happen

00:24 if we moved the Earth.

00:29 What's the Sun's problem anyway?

00:31 Well, like any other star,

00:33 it has an expiration date.

00:35 The beginning of its end

00:37 will feature our Sun swelling into a red giant,

00:40 wiping out everything that happens to be orbiting it too closely,

00:44 like the Earth.

00:46 If we wanted to survive,

00:48 we'd need to take action long before the Sun started going on a rampage.

00:54 It would take a billion space shuttles

00:56 to evacuate about 7.5 billion Earthlings.

00:59 Even if we could launch 1,000 space shuttles every day,

01:03 it would take over 2,700 years

01:05 to move everyone off the doomed planet.

01:08 Maybe we could save ourselves some trouble

01:11 by moving our whole planet instead.

01:14 That's actually quite possible.

01:16 We'd only need to give the Earth one big boost in the right direction,

01:19 and keep it on course.

01:21 And there are a few ways to do that.

01:25 To move the planet out of danger,

01:27 we'd have to change its velocity by 1,200 m/s (3,000 ft/s).

01:31 That would require about 7,000 of the most powerful rockets ever built.

01:36 But this plan has one big flaw.

01:39 To escape the Sun's expanding flames,

01:41 we'd need to escape pretty far.

01:43 At least move into the orbit of Mars.

01:47 Moving something as bulky as the Earth to a safe zone there

01:50 might take us billions of years.

01:52 And for every billion years that passed,

01:55 we'd use up about a third of the Earth's mass as propellant.

01:58 That's not very efficient, is it?

02:01 To move the Earth more efficiently,

02:03 we'd have to consider electric propulsion.

02:07 Unlike the chemical one used in most rockets,

02:10 electric propulsion doesn't require a lot of mass.

02:14 We could get away with sacrificing only 2% of the Earth's mass every billion years.

02:19 You'd hardly notice the difference.

02:21 But this option would require a lot of power,

02:25 about 800 times more than what's produced here on Earth right now.

02:30 Plus, it would take some careful engineering to make this work.

02:34 Because the Earth is spinning,

02:36 a rocket placed in one location would not always point in the right direction.

02:41 We'd need to place rockets all around the Earth,

02:43 and have each of them fire only for a certain amount of time.

02:47 That would keep the Earth on course.

02:50 It would take a billion years to move the planet out of the danger zone.

02:54 Any miscalculation could mean extinction.

02:58 There is a better way,

03:00 and it involves asteroids.

03:03 Aerospace engineers use something called a gravitational slingshot

03:07 to alter a spacecraft's path without using too much propellant.

03:12 When a spacecraft approaches the Earth and then leaves its gravitational pull,

03:17 it receives some of the Earth's orbital energy.

03:20 We could use the same effect to redirect our planet.

03:24 First, we'd have to make comets or asteroids pass close to the Earth,

03:28 transferring some of their energy in the process.

03:31 Next, engineers would redirect the asteroids close to Jupiter and Saturn,

03:36 where they would pick up some of the gas giant's energy.

03:40 From there, the asteroids would bring that energy back to Earth.

03:44 We'd repeat the process over and over again until it got us to a safe orbit.

03:49 Of course, that would be quite dangerous too.

03:54 The slightest miscount might redirect a gigantic asteroid right into the planet,

03:59 and destroy all life as we know it.

04:03 Now, we wouldn't be taking the Moon on our road trip around the Solar System.

04:08 Most likely, we'd ditch our celestial partner

04:10 the moment we pushed Earth's orbit away from the Sun.

04:14 Now, the big risk here is that moving the Earth might disrupt the whole planetary system.

04:20 It could easily destabilize Mercury or Venus,

04:24 setting them on the path of destruction.

04:26 And there's no one living on those planets that can save them.

04:30 At least, not that we know about.

04:32 Maybe we'd be better off terraforming another planet to use as our new home.

04:37 But that's a story for another WHAT IF.

04:41 [ ♪ Outro ]

Category

Transcript

Recommended