Flying rocks could explain the formation of planets in lightning

It takes illions of years for dust and gas parts, matter, to condense into planets. This is the most common theory of how the great celestial bodies of the solar system grew up. But there has to be – as everything suggests – a faster way to emerge on the planet. Researchers from Jülich and Belfast have now outlined a possible process in a thesis paper. The Jülich Supercomputing Center (JSC) announced this on April 8, 2019.

Interstellar objects such as Oumuamua , discovered in October 2017 , an object made of metal or rock with a diameter of around 200 meters, initially mistaken for a comet, play the decisive role in her theory . Susanne Pfalzner from JSC and Michele Bannister from Queen’s University in Belfast see these objects as a kind of “nucleus” that could give a planet “jump start”.

The researchers estimate that there are quadrillion (that’s a one with 24 zeros) of Oumuamua-like objects in the Milky Way, and around 29 trillion in a cube with an edge length of one light year. These asteroids roam freely in space after being thrown from orbit around their home stars.

Planetary systems form and then throw trillions of tiny worlds out into interstellar space. The scientists compare this to “dandelions that scatter their seeds”.

The crucial point: If the objects are now captured by the protoplanetary disk, a ring-shaped area made of gas and dust, around another star, the interstellar fragments can develop impressively.

“With their gravity, the asteroids could attract matter – gas, dust, small rocks – and eventually grow into full-fledged planets. This scenario would solve the problem with the rate of planet formation, ”the JSC announces.

Theory explains the rapid growth of some planets

“According to the usual so-called accretion model, it would take up to tens of thousands of years to get even millimeter or centimeter-sized matter from microscopic dust particles,” explains Michele Bannister. “The formation of earth-like planets then takes many millions of years, and that of gas giants like Jupiter even longer.”

However, there are planets that are only a million years old.

“If planets didn’t have to slowly build up from micrometer-sized dust and gas particles, that would accelerate their formation process enormously,” says Susanne Pfalzner. “When the idea came up, it made so much sense. I hope that many other researchers will take it up and test the model. ”This mechanism would also work back on itself: Systems with more planets throw out more rocks like Oumuamua, which then create more planets in other systems: a self at work holding process. In short: planetary systems help build new planetary systems.

It is probably not the rule that an Oumuamua-like chunk becomes a real planet. “Many of these objects are probably moving too fast to be captured by protoplanetary disks,” says Pfalzner. “And of those that are caught, most of them will likely fall into the star.” Nevertheless, the astrophysicists calculated that there should be at least ten million of these interstellar objects around each star.

“So most of them are lost in the capture process. But since there are so many of these objects, there are still plenty of them left in the end, ”explains Michele Bannister. “Thousands of them are probably over a kilometer in size. A few could be the size of dwarf planets like Ceres or Pluto – or like our moon. “

Astronomers discovered Oumuamua in October 2017 – just as it was about to leave our solar system. You just had time to measure the object’s movements with telescopes.