Planetary scientist Matthew Clement of the Carnegie Institution’s Earth and Planetary Laboratory and colleagues claim that aliens can alert us to their presence by moving the planets around.
Experts say that an alien civilization can organize entire solar systems of planets. They can also bombard moons and planets with asteroids to change their orbits and signify their presence, planetologists say.
According to astronomer Matthew Clement, this ambitious planetary shuffling will provide an opportunity for aliens to advertise their presence to us.
In a recent article in the Monthly Notices of the Royal Astronomical Society, Clement and his colleagues suggest that a sufficiently powerful and motivated alien civilization could create entire solar systems with planets.
Planetologists believe that this could be done with an object the size of an asteroid. To do this, it will be enough to direct it to the correct course in order to influence other planets with gravitational shocks, gradually moving them to different orbits.
“This actually happens,” Clement tells Inverse. “We are fairly confident that the Solar System’s giant planets moved around significantly after they formed, as they had repeated flybys with leftover debris and with stuff like Pluto.”
Scientists believe that doing such a thing is not entirely out of the realm of science fiction. Clement says there’s already serious speculation about using gravitational nudges from another small object to steer an asteroid into a closer orbit for mining.
And already now we are using the same principle to launch spacecraft into more distant orbits (or send them flying outside the solar system).
“It would take millions of years to have one asteroid, or a number of asteroids move a planet-sized thing that [necessary] amount of distance,” says Clement. That’s an order of magnitude longer than our species has even existed.
“But if you’re a more advanced civilization, maybe you could think on million-year timescales.”
A technologically advanced alien culture might find a way to apply gravity to an entire planet to change its orbit.
While it’s hard for us to imagine how to do that, Clement says that in terms of clean energy needs, any civilization tech-savvy enough to harness most or all of their star’s energy could do so in just over two (Earth) years.
“It is worth considering that any civilization can only broadcast itself for a short period of time,” says Clement.
Some technologies may outlive their creators – for example, our radio transmissions will propagate into space long after we’re gone, and Lageos satellites (a pair of laser reflectors in very stable orbits 5,900 kilometers above Earth) are likely to stay in orbit longer than The earth will remain habitable.