Moving The Earth

I'm placing this thread in Skunk Works, as while the ideas are based on real physics and science, the technology to do what I'm discussing doesn't exist at this time.

With so many threads that have been started up recently about "Nibiru", and other threads talking about the sun being hotter and brighter, I was reminded of a science fiction novel that I read as a teenager, way back when.

The novel is "A World Out Of Time" by Larry Niven, published back in 1976.

In this novel, a starship pilot (let me explain that: his craft was a buzzard ram jet, not capable of FTL), returns to the solar system about a million years in the future, only to find the solar system is not like he has left it.

The two biggest things were the fact the sun had become a much larger red giant, and the Earth was in orbit around Jupiter like one of it's moons.

I've asked myself: what would the sun have to be like in order for the Earth to be in orbit around Jupiter, but keep Earth's mean tempratrue that we have now?

Can you move the Earth, and if so, how?

Can you somehow "drop Earth off" at Jupiter so that it's in orbit around it?

One of the neatest things about being alive today is our access to computers and the software we use on them. When I was a kid, a digital calculator was a really cool thing to have. Forty years later and I have a personal computer sitting here in front of me that I play games like Skyrim and New Vegas on, who's computing power most scientist would have killed for back in the 60's and 70's.

One of the programs I have is Universe Sandbox. It's a sandbox program that allows you to play with the solar system, stars, planets (even galaxies) and their orbits, mass and how they affect each other. It's all point and click, so no programing experience is required.

Again, having some of the threads that we've seen this crazy year of 2012, reminded me of Larry Niven's book, and I thought to myself: Hey! Why not use your program to see what the answers are?

So being the astronomy/astrophotgraphy/astrophysics geek that I am, I fired up Universe Sandbox and went to town with it.

Many of the results I got were astonishing, and I'm going to share them with you here.

First, here is the stats for the Earth as we are, normally going around our sun with nothing changing:



"So if Earth were in orbit around Jupiter, how hot would the sun need to be so that Earth's temps stay the same as they are now?"

This was an interesting question, and I knew right away that I was going to have a problem. I needed to somehow increase the sun's surface temp and brightness, but leave it's mass alone.

Why do I need to leave it's mass alone? You'll see what happens if you change the sun's mass. It's not a good thing.

So first we move the Earth and put it in orbit around Jupiter (we'll worry about how we do this later). With the sun being as it is now, you can see that things get very chilly on Earth. Average suface temp drops to around -146 deg C. Brrrrrrrrrrr!





After playing around, I found that if we increase the sun's surface temp to around 10,000 k and increase it's brightness to 27 times how bright it is now, the Earth's surface temps go back up to about where they are now, averaging around 15 deg C. Ahhhh! Much more temperate.



In Larry's book, a war between immortal Girls and Boys is what cause the sun to become so hot, by some how increasing it's nuclear reaction. In his book the sun was a red giant.

Our star, after I increase it's surface temp and luminousity to 10,000 k and 27 is more like a blue white star.

Is there a star like that? Why yes! Sirius is like that! It's surface temp is 9770 k and it's luminosity is 22.2 times that of the sun. When I put it in place there, the Earth's temp is warm, but it's a bit chilly, as the Earth's average temp drops to about 3 to 4 deg C, so we'd have another ice age.

Drifting a bit off topic, here's a picture showing the relative sizes of our Sun, Sirius, Wolf359, and that huge, bloated thing over 8 AU's across is Betelgeuse!



Here is what Betelgeuse would look like if we replaced the sun with it:



And get this, even if I put Betelgeuse over 170 AUs out, the surface temps on Earth scream up to 79 deg C:



Okay, back on topic.

So if I used Sirius as an example to increase the sun's surface temp and brightness, it would still leave Earth a bit cool, at about 3 deg C. But it won't stay that way for long. Sirius mass is 2.02 times that the the sun. This messes with the orbits of the planets and makes them eccentric. This bring's Jupiter in very close and Earth's temps get over 160 deg C. Here is a video of that:



So I've determined that if the sun were to increase in it's surface temp to about 10,000 k and become 27 times more bright, but keep it's mass to 1 sun, that if Earth were around Jupiter, our temps would be comfortable (and awsome looking skies as we watch Jupiter rise from the horizon that close!).

Now we need to move the Earth.

So how do we move the Earth?

You can't just build some sort of mega rocket system for it. How would you mount it? Worse, if you found a way to mount it, the thrust needed would cause mega tsunamis as the oceans sloshed around, and mega quakes as the Earth's faults are subjected to extreme amounts of thrust.

So you don't move the Earth.......you move a much larger planet!

In Larry's book, they needed to move the Earth away from the sun as it became too hot. They decided that the best way to do this was to use the gravity of another large planet. The gravity of that planet would capture the Earth so that it orbited it instead of the sun, and then move the planet out. The planet they decided to use was Uranus. They built these huge rocket motors that were able to stay up in the atmosphere of Uranus and use it's atmosphere as it's fuel.

So I decided to try this. I don't have huge rockets in Uranus atmosphere, but I do have Universe Sandbox and can put planets where I want them, change their speed and orbits.

Using Uranus was a disaster. It's 15 Earth masses so it's big enough to capture the earth, but in order to move the Earth out further, you need to increase the velocity of Uranus. Doing this would make Earth's orbit around Uranus unstable and I ended up loosing the Earth, or worse, the Earth would spiral in and impact with uranus!

So I decided to use Neptune instead. It's 18 Earth masses, so it masses more than Uranus. It captures the Earth just fine, and as I increase it's velocity, it's orbit moves away from the sun, but it's able to hold on to the Earth just fine and take it for a ride.



Have to be careful though, get Neptune too close and the Earth becomes an impact site:



So now how do we hand the Earth off to Jupiter?

We bring Neptune in so that it whips around Jupiter but it's approach velocity is about 14 km/s (while Jupiter's orbital velocity is at about 13 km/s, and time it so that the Earth's orbit around Neptune brings it within 4 million km of Jupiter.
At that point, we have to quickly increase Neptune's velocity to about 28 to 30 km/s. We need to do this within a few hours.



What happens is the Earth is left behind by Neptune, and Jupiter's stronger gravity takes over. The Earth is now in orbit around Jupiter!

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While other than being theoretically interesting, what would be the point in moving the Earth? Well in about 5 billion years the sun will expand into a red giant, leaving Earth a burnt cinder. And while I have to wonder what a human being might be like 5 billion years from now, or even have a need for Earth at all, the fact remains that in that far off distant future, theoretically, someone could move the Earth out further and further from the sun as needed, simply by using another giant planet as a tug boat.

I've read most of Larry Niven's books (except some later ones) and they were very good (IMO) - albeit outdated now following more recent discoveries.

Although I know of the story, I can't actually remember reading World out of Time though ....

Anyway, one issue with moving the Earth is that we would have to maintain it's rotation - else we'd see windstorms and tsunamis that'd make even Betelgeuse look small!

An interersting project though, to work out how it could be done


Edit: just checked on Amazon and I'm certain I never read this book for some reason. Time to order a copy!

first off.. i have to buy "A World Out Of Time". seems like a great book to get me reading again.

Launching a billion 10-tonne rockets in exactly the same direction would change the Earth's velocity by just 20 nanometres per second - peanuts compared to the planet's current speed of 30 kilometres per second.

newscientist: moving the earth

so rockets would never ever work.
hmm if i look at sci-fi , sg1 put a meteor headed for earth into hyperspace which made the meteor travel at "warp speed" through the earth in subspace so it wouldn't collide.
futurama had a giant star mover.
many deathstars with a massive towing cable.

no real way i can see us doing that though. cant play pool with planets
evacuation to another planet is the best option although we'd need many many rockets and shuttles.

How would you maintain temps while moving the earth?

Very interesting S&F

reply to post by VoidHawk


Actually our atmosphere would protect us for a time, and we could probably increase CO2 levels or something to retain heat for longer. Failing that we go underground for the duration.

Though I assume in the proposed scenario, the issue would more likely be how do we stay cool until be move to a more temperatate orbit?

here is io9's take on this idea apparently there has been more thought about this than you might imagine

reply to post by AndyMayhew


Have you read
Peter Hamilton - Pandora's star etc etc
Alastair Reynolds - Absolution Gap etc etc

If the scifi writers are anywhere near correct about our future I dont think we'll be moving the earth, we'll be creating our own worlds.

Originally posted by VoidHawk
How would you maintain temps while moving the earth?

Very interesting S&F

In the book, they had to put up some sort of huge reflector to block most of the sun's light until they could get Uranus close enough to do it's job.

I can't remember exactly the time line, but at the time it was like tens of thousands of years into the future. Who knows what technology we'd have by then?

In the book they had to keep moving the Earth further and further out, until finally the sun stablized, but put it put the green zone in Jupiter's orbit. However, when they got the Earth into orbit around Jupiter, and one or several of it's moons spiraled in, causing some sort of reaction with Jupiter and it heated up some too, making only Antarctica the only habital place on Earth. They were going to bring Uranus around again, but the extra heat from Jupiter was too much for them and their civilization fell.

All fiction, but a great read.

That's easy.

Now since we live in a multiverse where every possible outcome is conceivable it's fare to say that, that configuration all ready exists but just in another frequency.

Now how to access that, is the real question?

This is the exact same as saying why do we have 7 billion different people on the earth, for if the human race was limited to just 3 or 4 versions then our reality's would be limited as well.

Or just to go a little deeper we have billions of different life forms on earth each living in there own reality how could we live in a universe that only has one version, not a possibly.

enjoy.

The sun would only grow slowly.
so you would move earth out slow to.
but as you got close to jupitor the gravity would be all over the place.
all the moons of jupitor. so you would need to stop gravity slowly.
inertia would need to be stopt to.

and you would need a heat sheild around earth.
it would be a lot easer to put earth on the far side of jupitors orbit.

"Gravity tugs" are fun - but I can't help but think that such an effort would also cause massive tidal and tectonic shifs on earth - I have no way of knowing how much, but I dont' see why they would necessarily be any less violent than using big rockets attached by strong strings

reply to post by Aloysius the Gaul


I think if I remember right, the idea was to have Uranus make several passes to "slow" the Earth down in it's orbit and capture it "gently" (er, at least I think that was the idea).

The people in the book lived immortal lives (the never Aged, but could die from violence, etc), and I think the long periods that it would take to do this (making several orbits close to earth to gently slow it down and then capture it) was the idea.

We know tidal forces would cause hell down here, but I think it would only happen if it was sudden (Uranus or Neptune "pops" into existence right by the Earth), or if either got way too close too fast.

Still, we don't know, as we've never experienced this, so it's all theoretical. I do know that we get surprised a lot, hehehehe.

Just as I said last night, brilliant! S&F for you!

I suspect that, in five billion years, give or take a billion, we will have developed propulsion technology to move large objects, and I agree that, rather than moving the Earth directly, we would utilize another body to do it. But wouldn't something smaller, like Venus, be able to accomplish the same thing? Riskier, because it would need to be closer to Earth, but I think you could "walk" the planet out fairly well, give enough time.

Unfortunately, as I wrote in a separate thread last night, it's only delaying the inevitable, lol:

It's the End of the Universe As We Know It...

,attach a cable or snatch strap to rocket ,
attach the other end to a point on earth ,probably at one of the poles on a large bearing set up to avoid twisting of cable
Send rocket to Larger planet and attach cable to it.
winch Earth toward larger planet
Put on warm clothes and wait.

Originally posted by 12voltz
,attach a cable or snatch strap to rocket ,
attach the other end to a point on earth ,probably at one of the poles on a large bearing set up to avoid twisting of cable
Send rocket to Larger planet and attach cable to it.
winch Earth toward larger planet
Put on warm clothes and wait.

lol, points for coming up with a quick, but massively untenable concept. The planets in question are moving at different rates, so what is your "load test rating" on that cable? Cause that sucker is going to snap quicker than a 3 pound test line is gonna snap on a muskie.

reply to post by adjensen


Havent worked out the minor details yet
,but it wouldnt be much different than pulling a 4x4 out of the bush ,I imagine
scaled up of course.What was the point of moving it again?

Definitely a very interesting idea and possibilities. Great job OP on all the detail and thought processes, that program you found is really cool. I might download it myself sometime and play god with the universe haha.

Though I have one question is, what do we do about our moon? That is what controls the tide of the oceans and many other things with its gravity pull on us. I could be totally wrong but I think we would have to move it as well or at least get a replacement from Jupiter if we are way out there. We may have the right temp but without our moon we would lose our normal ebb and flow of things that happen on Earth and cause utter chaos. Other than that, I think if we have technology to move planets then we might as well just make a couple of Deathstars and have essentially movable mini-planets.

Also to the poster above me with attaching cables from Earth to another planet is definitely funny. Forget the physics and forces involved, just imagine how long that cable would be! I'm not even sure if we would have enough room on the planet to make a cable that big haha.

Well,if you had the energy to move the earth literally, it would have to be the energy of a black hole in reverse

reply to post by deathlord


The main solar system simulation doesn't have the moons around the planets, however you can put them in (I hear the next update will have the moons there automatically for the Solar System simulation). I believe it would move with us, but would have it's orbit around earth affected.

But I imagine they'd be able to "fix" it's orbit too, if you can move a large planet like Uranus or Neptune around to move the Earth, then changing the moon's orbit should be easy peasy, heh.