An artificial planet can be created by an advanced civilization. Even if our current technology is unable to create this, we can see the benefits of it.
By using various future technologies, it is possible to create a large cosmic object, like a planet or a large satellite. There are two methods:
Dust accretion Edit
This can be used to condense dust from a large cloud, even a protoplanetary disk. To change the orbits of many small-sized particles and space rocks, current technology offers no solution.
- One can imagine a giant trawl, collecting dust and compacting it into larger boulders, that are carried by spaceships.
- The effect of light on dust is known from comet tails. However, the energy needed to push all the dust needed for a planet is simply too much. It can be cheaper to collect and move the dust.
- Another idea is to move a larger object, like an asteroid, through a dust cloud, so that its gravity can collect all the matter.
- A more advanced technology is able to change the fabric of space and to create artificial gravity. This might prove more useful.
Asteroid belts and rings Edit
Can we create a planet from the asteroid belt? Unfortunately, the mass of all asteroids is only 4% of that of the Moon . Other stars might have a larger planetoid belt, massive enough to create a planet. Engineers will have to slowly divert the orbits of all asteroids, so that they can be set on a collision course. The impacts must not be violent because, at their low gravity, asteroids might tear apart instead of creating a larger body. The process will take tens of years, but the result will be a larger body, with enough gravity to support an atmosphere.
In case of planetary rings, the problem is more different. Rings are placed inside the Roche limit, so that a large body will break apart. So, even if somehow we collide the particles together, the newly formed object will not resist. In order to create a new moon, matter from the rings of Saturn must be pulled away from the planet.
Collisions of larger bodies Edit
In many places, there are asteroids, dwarf planets or complex moon systems. These objects might be too small to support an atmosphere on their own. However, if we somehow make them collide, we can create a larger body. For the Solar System, by slowly pushing the moons of the gas giants, we can create this (they are my own calculations):
- By colliding the four Galilean moons, we can create a body with a diameter of 7000 km.
- By colliding all moons except Titan, we can achieve a body with a diameter of 2500 km.
- By colliding all moons of Saturn (Titan included), the resulting body will have a diameter of 5500 km (not much then Titan itself).
- By colliding all moons of Uranus, we will get an object with a diameter close to 2000 km.
- By colliding the dwarf planets from Kuiper Belt, we might be able to create something at the size of Earth's moon.
The new planet Edit
Assuming a composition similar to Earth, the newly created object will be at first a fireball of molten lava. Settlers will have to wait millennia for it to cool down, except if a special technology is used for that. If the bodies involved in collision contain too much water ice (like the moons of gas giants), this water can be lost during impact (by the impact itself or by evaporation because of the resulting heat).
When temperatures will drop enough, the crust will be thin and fragile. Quakes and volcanos will be frequent. The extreme volcanism will affect the atmosphere and all ecosystems. Terraforming an extremely volcanic planet can be difficult.
The lack of matter Edit
Small sized objects are light. Sometimes, their combined mass is too small to create a large enough body. For example, the combined mass of the Asteroid Belt is only 4% the mass of Earth's Moon. The combined mass of all other moons of Saturn is only 8.5% the mass of Titan. And the combined mass of the moons of Uranus is less then the mass of Saturn's moon Rhea. The combined mass of the entire Kuiper Belt is estimated to have between 1 and 10% the mass of Earth. Because of this, in majority of cases, there might not be enough matter to create an artificial planet.