When it comes to cosmic survival, it’s not only the survival of the fittest but also the most coordinated.
As planets orbit around their common host star, astronomers have often wondered what keeps them from crashing into each other while in orbit.
However, they failed to determine what makes for orbital stability, and what makes planets like the ones in the Solar System survive the test of time, and gravitational pull?
A team of researchers may have found the answer, developing an artificial intelligence system aptly named SPOCK (or Stability of Planetary Orbital Configurations Klassifier) which determines which star systems will fail and which ones will live long and prosper.
The was published this week in the Proceedings of the National Academy of Sciences journal, and provides astronomers with helpful insight when trying to find worlds outside of the confines of the Solar System.
Planets are born from clouds of dust, gas and rock that encircle a young star.
For multi-planetary systems like our own Solar System, there are many things that could go wrong in terms of how they orbit around their host star.
There are many orbital configurations that are deemed unstable, and will likely spiral into quick doom as planets cross over each other’s orbits in a matter of millions of years.
, a NASA Hubble Fellowship Program Sagan Fellow in astrophysical sciences at Princeton, and lead author behind the new study, said in a that the problem was “brutally hard”:
“Separating the stable from the unstable configurations turns out to be a fascinating and brutally hard problem.”
An illustration that shows two possible orbital configurations for the Kepler-431 system, with the left-hand image showing unstable orbits of the three planets.D.
Tamayo et al./Proceedings of the National Academy of Sciences 2020
Astronomers have had to observe planetary systems for billions of years, calculating the motions of the planets around the star and determining the possible configuration for stability.
However, the team behind the new study turned to super computers to simplify this long and tedious process by combining simplified models of the planets’ interactions, and machine learning.
The process begins by simulating 10,000 orbits and calculating 10 summary metrics of the planetary system’s dynamics.
And then, in comes SPOCK.
system predicts which of these 10 features would have a stable future if it kept on going, up until the planets orbit around their common host star for about one billion times.
“We can’t categorically say ‘This system will be OK, but that one will blow up soon,'” Tamayo said.
“The goal instead is, for a given system, to rule out all the unstable possibilities that would have already collided and couldn’t exist at the present day.”
SPOCK is speedy, operating at 100,000 times faster than the traditional method of determining the orbital stability of a planetary system.
By speeding up this process, astronomers get a better understanding of what are some of the factors that lead to a system’s speedy failure.
By doing so, astronomers are able to identify the composition and properties of exoplanets, or planets that exist outside of our Solar System.
“This new method will provide a clearer window into the orbital architectures of planetary systems beyond our own,” Tamayo said.
Some exoplanets are too small to directly observe by a telescope, and it is therefore difficult to determine their orbits around their host stars.
However, this new method establishes models of stable planetary orbits that could be applied to these faint, distant worlds.