Scientists have used the “perfect harmony” of a distant planetary system to understand more about its past.
The best known is the star TRAPPIST-1, which NASA has called the “holy grail” solar system that looks remarkably like Earth. Since that discovery was first announced in 2017, astronomers have learned more about the system, including whether it contains more planets and may be home to life.
However, scientists are still discovering more about those worlds, despite their vast differences from Earth. In new research, astronomers have used the “near-perfect coherence” of the seven planets’ orbits in the TRAPPIST-1 system to better understand their past.
The harmony shows the astonishing cleanliness of the orbits of the different planets in the system. They are arranged in precise proportions, much like an arrangement of harmonious musical notes: for every eight years on one planet, five years pass with the next one, and they continue in such precise relationships.
The new research allows scientists to better understand the impact history of those planets, or what accidents they must have gone through when they were in their infancy. Doing so could help to better characterize whether planets might contain the water and other materials needed to start life.
“After rocky planets form, things bump into them,” astrophysicist Sean Raymond of the University of Bordeaux said in a statement. “It’s called bombardment, or late accretion, and we care about it to some degree, because these impacts can be a significant source of water and life-promoting volatile elements.”
Studying those impacts is quite difficult on Earth, and must be done by measuring particular elements and comparing them with the makeup of meteorites. This is apparently impossible to do in a system like TRAPPIST-1, which is 40 light-years away – and so scientists had to rely on more complex methods.
“We’ll never get the rock from them,” Raymond said. “We’re never going to see craters on them. So what can we do? This is where TRAPPIST-1’s special orbital configuration comes in. It’s kind of a lever we can pull to put a limit on it.” Huh. “
The researchers were able to estimate how much bombardment the planets must have gone through before breaking out of that clean and resonant harmony. It helps establish what could have happened to those planets.
“We can’t say how much stuff hit any of these planets, but because of this particular resonance configuration, we can put an upper limit on that,” Raymond said. “We can say, ‘It couldn’t have been more than this.’ And it turns out that that upper limit is actually quite small.
“We learned that after these planets formed, they weren’t bombarded with very small amounts of the stuff,” he said. “That’s great. It’s interesting information when we’re thinking about other aspects of the planets in the system.”
The findings help scientists tell the story of the TRAPPIST-1 planets. They would have formed sooner and faster – about ten times brighter than Earth – but not bombarded by much, which helps to understand what might be happening inside those worlds and how its atmosphere might have formed.
But scientists note that there is much more to learn about the system. Future examination by projects such as the upcoming James Webb Space Telescope could help get rid of some of the unknowns in the new research.
Credit: www.independent.co.uk /