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The next time you’re worried that your collecting habit is fading, you can try some self-compassion knowing that the sun is a bit of a collector too.
But, instead of hoarding comic books (guilty as charged), baseball cards, vintage trainers, or Pokemon cards, the sun has sprung up to run rogue planets – and it’s not picky. The sun is capable of capturing minor planets as well as Jupiter-sized gas giants that get too close; Our star then holds them at the edge of the solar system.
As any collector will tell you, trading is one of the main parts of any collecting hobby – and the solar system does this too.
It is able to exchange its valuable rogue planets with the planets plucked by its nearby star system, Alpha Centauri. And new research suggests that life that has left the solar system could orbit its edge for billions of years before drifting closer to the sun and causing chaos in the inner solar system.
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Scientists have suspected for some time that the solar system can capture inflowing objects, such as comets and asteroids, collecting them outside the Oort cloud, which is believed to be a spherical shell of trillions of bodies. icy outer edges of the solar system. .
The new research shows that this “capture region” extends far beyond the Oort cloud, however, which is about two light-years from Earth (about 126,000 times the distance between Earth and the sun). The work also shows that our planetary system is capable of attracting bodies much larger than comets or asteroids.
“ has found that when objects are captured into our solar system, the distance to which they can be captured is much greater than previously thought,” said Edward A. Belbruno, research author and professor of mathematics at Yeshiva University with Space.com. “ have found that there are objects that can be captured from about 3.81 light years away, which is close to another star system, the Alpha Centauri system.”
Although our solar system would not be able to capture an object with a mass around or greater than the mass of the sun, as this would interfere with the sun’s gravitational influence, it is able to collect rogue planets with masses reaching Jupiter, that is to say. a thousand times less massive than the sun.
“It’s a very interesting result,” continued Belbruno.
Adopting a cosmic orphan
Rogue planets are worlds that have been expelled from their own planetary systems. This can happen when a passing star disrupts the gravitational stability of the planetary system or simply through natural disturbances in a young star system.
The Milky Way is thought to have a large number of free-floating rogue planets. There may be as many as a quadrillion (10s followed by 14 zeros) rogue planets in our galaxy that have been kicked out of their home systems to roam the Milky Way as cosmic orphans.
While much research focuses on how rogue planets can be banished, fewer studies focus on the possibility that these celestial orphans can find new homes.
The two scientists behind this research, including former NASA expert James Green, discovered something surprising about this capture of past rogue planets. There really is two stable gravitational points, or “Lagrange points,” where ensnarement can occur, Green realized.
“You have two whole regions, little openings, where things can come into the solar system at those two Lagrange points,” Belbruno said. “One point toward Galactic Center; one point away from it.”
The mathematics professor, who has a passion for celestial mechanics, explained that when rogue planets enter the solar system at these openings, they will first begin to move very slowly around our sun, with a distance of about 3.81 light years for about 100 million. years. After this period, they will begin to spiral inward, a process that could take billions of years.
Belbruno explained that one interesting factor he and Green found about this migration is that the new addition to the solar system will orbit in a pattern known as a “fractal curve.” This is a mathematical curve with a shape that repeats the same pattern of irregularity as it increases. A famous example of this is the Mandelbrot set. “You get these really cool curves, especially as the object gets closer and closer to its capture location,” Belbruno explained.
They must catch them all!
Although the sun is not picky about the mass of the planets it holds, it has one criterion for its collectable orphan planets.
Belbruno explained that he would have to travel at a fairly slow speed of a few hundred miles an hour to capture a rogue planet. That’s incredibly fast by Earth standards, but it’s a cosmic rip off when you consider that runaway planetary mass objects have been detected at speeds higher than 1.2. million miles per hour (1.9 million kilometers per hour).
The slow velocity of these rogue planets means that there could be a reservoir of such objects orbiting the sun for billions of years (distance up to 3.81 light years).
What if a trapped rogue planet worked its way into the solar system? Well, Belbruno said that this effect would depend on the size and mass of that planet.
“We assume that the world was the size of Jupiter and came flowing into the solar system,” he said. “A Jupiter-sized object entering our solar system would cause the orbit to shift significantly in some sense. It would have immediate effects on the dynamics of the Earth’s motion around the sun, and that would certainly affect life on this planet.
“It is not inconceivable that this could be some planets of the solar system going rogue themselves.”
Of course, the rogue planet may never enter the inner solar system. As mentioned above, orbiting the sun for 3.81 light years would bring a captured rogue planet very close to Alpha Centauri, which can capture its own rogues and keep them at a distance.
That means that the two star systems could trade their trapped rogues, like kids trading baseball cards.
“Our solar system’s gravity goes out close to Alpha Centauri, so that would mean that Alpha Centauri’s capture zone goes very close to our own sun’s capture zone,” Belbruno said. “The two systems are completely overlapping in terms of gravitational effect, and this means that things going back and forth would be very, very natural.”
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The scientists’ work is currently based on mathematical modelling, with Belbruno pointing out that because rogue planets emit very little light, it would be extremely difficult to spot one beyond the Oort cloud.
One helpful factor in the search is the fact that Belbruno and Green both localize the capture centers, and these Lagrange points are a natural place to start hunting for adopted orphan planets. Such a search may be beyond the capabilities of current telescope technology, although the James Webb Space Telescope (JWST) could see the thermal emissions of such a world in infrared light.
“There could be a lot of things out there in retention patterns, sort of spiraling around the sun,” Belbruno concluded. “If they come in, they can’t get out – even if they entered the solar system 4 billion years ago. It’s certainly possible that rogue planets have already been captured.
“We just don’t know.”
A preprint of the study can be viewed on the arXiv paper repository.
