Building an Artificial Planet

Building an Artificial Planet

Whether it's human activity or a giant meteor crashing into us, planet Earth is not going to last forever. Eventually, the lump of space rock that we call home will one day no longer exist. So what will we do as a species if this were to happen? The obvious plan is to reach out into the universe and build colonies elsewhere. But space travel is incredibly complex, and we're still not sure if it's even possible to reach another solar system within a reasonable amount of time.

But what if we built an entirely new planet ourselves? We see artificial planet-sized objects quite often in science fiction, from the Death Star of Star Wars to the planet-building facility in Hitchhiker's Guide to the Galaxy. And even far larger objects like a Dyson Sphere. The species shown being capable of building such creations are, of course, incredibly advanced. But what exactly would it take to actually build one?

It first depends on what you mean by the question. Are you talking about a replica of a planet like Earth, or a space station that's the size of a small moon or planet? The former would require a careful combination of elements and mass, while the latter would still require enormous engineering feats, but maybe not quite as difficult.

The most famous planet-sized space station from sci-fi is, of course, the Death Star. According to estimates, the construction of such a structure, which is 74 miles in diameter compared to the Earth's 8,000 miles, would require materials that weigh approximately one quadrillion tons. That's about a millionth of the weight of Earth.

Supplying all the material would be a mammoth task and impossible with current technologies. For example, on Earth, we produce about 1.5 billion tons of steel per year. This means it would take more than 800,000 years to produce enough for a moon-sized space station. Furthermore, it would cost about 852 quadrillion dollars. And that's not even taking into account how we would transport them into space.

But let's say we could do all that. Once it's there, the construction would actually be relatively easy. We could use robots to complete most of the work. And the lack of gravity means it wouldn't be too difficult to move all the materials into place. It would take a long time, but eventually that would be possible.

The alternative would be to mine all the materials from asteroids that are in space already. A number of companies are actually looking at the feasibility of doing this, with some tests already underway. If successful, it could vastly reduce the cost of building things in outer space. This may also be a better plan because it's not even certain that steel would be strong enough. We may need to create artificial gravity, which can be done by spinning the station. And the force this would exert could crumple steel. So some researchers think a carbon-based material harvested from asteroids would be much better suited to the job.

Now, despite the difficulties with building a moon-sized structure, creating an actual planet is a much, much bigger problem. After all, the Earth is already 4.5 billion years in the making. So how could we possibly replicate that?

Well, we wouldn't actually have to perfectly replicate the Earth to get similar conditions. For example, gravity is related to mass. So we could put the equivalent of one tenth of the Earth's mass of rock into a shape the size of our moon to get the same result.

There's so much rock and debris in space, and our planet itself was formed by enough of it collecting together. So if we could develop technology that did this for us, we'd be off to a really good start.

Following this, some have suggested we could build a fusion facility near the Sun, which could produce some of the heavier elements that are needed. These dense metals could be layered on top of each other, allowed to cool, and then they would form a stable structure.

The problem with this is that it would take tens of thousands of years to complete.

While building a planet completely from scratch is far beyond our capabilities, the idea of terraforming an already-formed planet is far more within the realms of possibility. Nuclear detonations could be used on Mars to warm the planet's atmosphere, and NASA has suggested that an artificial magnetic field could be created to deflect solar winds in the same way that a naturally-formed one would.

It's thought that this type of structure would allow Mars's atmosphere to thicken, which would warm at about 7 degrees Fahrenheit. And in turn, melt the polar ice, which could contribute to a greenhouse effect and warm the planet further.