Categories: Guide to Space

# How Can We Move the Earth?

Sooner or later we’re going to want to move the Earth further away from the Sun. It turns out, there are a few techniques that might actually make this possible. Not easy, but possible.

You live here. I live here. Everybody lives here. For now.

In 500 million years the gradual heating of the Sun will burn away all life on Earth. Then we might have to move. Even if we get past the 500 million year deadline, the Sun will die as a red giant in about 5 billion years.

Let’s review our options? We could die… orrrr we could move the Earth. Just like any other mad science scheme, there’s a hundred ways to skin this cat. We could launch powerful rockets off the Earth, which would push the Earth a little bit in the opposite direction.

We could build a giant teleporter and disassemble the Earth atom by atom into a new location. We could repeatedly smash things into the Earth. Eventually knocking it off orbit, possibly also changing its axis and or rotation.

We could paint half the Earth silver, stop it rotating and let the Sun push it away. We could dig a giant hole down to the core and repeatedly detonate warheads inside the Earth forcing molten material to fly off into space, propelling us forwards like a deflating balloon.

Sure, maybe that does all sound a little crazy. We could build a gravity tug, and slowly pull the Earth away from the Sun. What’s a gravity tug? I’m so glad you asked.

You could build a solar sail with a huge mass connected to it. This gigantic weight would want to fall towards the Earth, and the Earth slowly drifts towards the weight. The solar sail is being pushed away by the Sun dragging both the weight and as a result the Earth along with it. This would take a very, very, very long time.

Here’s the best idea scientists have come up with so far. Gravity assists: Attach rockets to an asteroid, comet or Kuiper belt object and have it fall on a trajectory that takes it close to the Earth. Earth and this space rock would exchange a little momentum.

The rock slows down a bit and goes into a new orbit, and the Earth speeds up a little. That additional momentum pushes our orbit up a tiny little bit, and now we’re further away from the Sun. You’d need to do this tens of thousands or even a million times.

You might think, “Hey, that’s crazy. Where would you get all this stuff to hurl past the Earth?”. Don’t worry, the Oort cloud alone has billions of objects with a total of 30 times the mass of the Earth.

To prepare for Roastpocalypse, If we started now, we should cause a close pass with a large object every few thousand years. We bring them within 10,000 km of the surface of the Earth, which would have the likely side effect of causing severe tides and storms.

Oh, and get the math wrong and you’ll smash an asteroid into the Earth. Just so you know, these would be way bigger than the object that killed the dinosaurs. One hit from a 100km diameter object would sterilize the biosphere.

If we pushed the Earth out to about 1.5 times its current orbit, which might get a little too cozy with Mars for comfort, we’d give the Earth another 5 billion years of habitability,

Then the Sun turns into a red giant, and then dies as a white dwarf. And nothing can help us then… except perhaps some kind of planet sized star gate.

What do you think? What’s the best suggestion you’ve got to move the Earth out to a safe distance? Tell us in the comments below.

Fraser Cain

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

• dontno says:

Funny I was looking up weather we could move Venus into a nearer earth sun orbit and it's exactly the same plan.
Not 100% it's the best plan I'm hoping one day we are capable of using ships so when earths doomed evacuate to another similar planet after all we have a few million years to think about it

• mba117 says:

Why was my first comment not accepted?

• Laced says:

There are over a billion objects in the Oort Cloud with 30x the mass of the earth??

I think that was a misplaced modifier (or dangling modifier? Not sure) and what you meant was there's a billion objects amounting to a total mass of 30x earth....? Otherwise that'd mean there's a billion huge ice giant planets out there... Right?

• Laced says:

Oh, the article here has it right. I think u might've just misspoke on the videocast version. Or maybe I'm just a poor listener lol

• Zoutsteen says:

Helliconia from Brian Aldiss had a nice idea about using a wheel.

But which ever option we choose, I think it will fail due to orbital resonance.

• FarAwayLongAgo says:

My suggestion of how to move the Earth during 500 000 000 years? Everyone just needs to jump once every morning! And the Earth will move away from the Sun. Jump for life. And it's kind of healthy exercise too. Although billions of jumping humans will get hurt by doing so daily during half a billion years, but it's worth the sacrifice.

(I do understand how this doesn't work even in the most abstract theory, but it's fun to confuse those who don't)

• iO says:

What if we wait until Earth and Mars line up and then (somehow? Some sort of slingshot action) swing around each other to swop places? Perhaps an intermedia tort body to capture both planets and swing them round would work.

• iO says:

That's Intermediary.

• qraal says:

Forgive the name-dropping but David Brin suggested, at last year's "Starship Century" book launch during a lunch break, that we use the Moon as a gravity tractor and propel it via a giant solar-sail or magnetic-sail. Not a silly idea. When the Sun goes off the Main Sequence the luminosity will be about twice current levels. That's in 5.5 gigayears, but it'll remain at about that level for another 2 gigayears while cooling and the core slowly contracting. Red Giant phase won't really kick-in for about 7.5 gigayears.

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