Slashdot Mirror
Asteroid From Another Star System Found Orbiting Wrong Way Near Jupiter (theguardian.com)
Astronomers have spotted an asteroid orbiting our sun in the opposite (retrograde) direction to the planets. The 2-mile-wide asteroid, known as 2015 BZ509, is the first "interstellar immigrant" from beyond our solar system to remain, according to the study published in the journal Monthly Notices of the Royal Astronomical Society. The Guardian reports: Further work on the asteroid revealed it takes the same length of time to orbit the sun as the planet Jupiter at a similar average distance, although in the opposite direction and with a different shaped path, suggesting the two have gravitational interactions. But unpicking quite where the asteroid came from was challenging. Asteroids that orbit the sun on paths that take them between the giant planets -- Jupiter, Saturn, Uranus and Neptune -- are known as centaurs, and it is thought that many might come from distant bands of material within the solar system such as the scattered disk or the Oort cloud. Several, like BZ509, are known to have retrograde paths, although how they ended up on such orbits is unclear.
But there was a clue there was something unusual about BZ509: while previous studies suggested retrograde centaurs stay gravitationally "tied" to planets for 10,000 years at most, recent work had suggested this asteroid's orbit had been linked to Jupiter for far longer, probably as a result of the planet's mass and the way both take the same time to orbit the sun. The discovery provides vital clues as to the asteroid's origins. [Dr Fathi Namouni from the Observatory de la Cote d'Azur said] that the model suggests the most likely explanation is that the asteroid was captured by Jupiter as it hurtled through the solar system from interstellar space. "It means it is an alien to the solar system," he said.
But there was a clue there was something unusual about BZ509: while previous studies suggested retrograde centaurs stay gravitationally "tied" to planets for 10,000 years at most, recent work had suggested this asteroid's orbit had been linked to Jupiter for far longer, probably as a result of the planet's mass and the way both take the same time to orbit the sun. The discovery provides vital clues as to the asteroid's origins. [Dr Fathi Namouni from the Observatory de la Cote d'Azur said] that the model suggests the most likely explanation is that the asteroid was captured by Jupiter as it hurtled through the solar system from interstellar space. "It means it is an alien to the solar system," he said.
oooW
Actually, they have do idea if it is the first extra-solar visitor or not. It is simply the first one they have noticed, and that was only because of its peculiar orbit. There could be a hundred others that either orbited with the planets, or that crashed into a planet or the sun. We'll never know.
If you think I voted for Trump because of this post, you're wrong. I voted for Dr. Jill Stein of the Green Party. Again.
Now we know how our Octopodian Overlords got here.
The only remaining loose end to this mystery is whether they consider Pluto a planet.
Sheesh, evil *and* a jerk. -- Jade
Are you sure it isn't just a British asteroid?
Nae king! Nae laird! Nae yurrupiean pressedent! We willna be fooled again!
In any space game this unusual object would certainly be an important artifact.
In reality it would still be quite interesting to analyse its composition.
This is speculation, but in principle we can get retrograde orbits if an asteroid -- even one on a "normal" orbit direction -- passes in front of a planet (relative to its path in orbit) and gets slingshot back around exiting at a ~200-300 degree angle. Whether this is possible in practice depends on the relative asteroid speed and mass of planet.
"interstellar immigrant" ? They can be stopped!
-Unresolved symbol? Byte me!
.fff
Lets build a Dysonsphere along the Oort Cloud and have the Alpha Centorians pay for it.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
It can just as well be, that it merely got turned around by getting too near to Jupiter and swinging around.
It is a well-known hypothesis that Jupiter protects the inner planets from asteroids coming from the outer solar system.
I see no conclusions being "jumped to".
A Differential hypothesis is the bedrock of science. Make the hypothesis, then try to disprove it.
In fact, your first sentence is a hypothesis. Your second sentence is in defense of it
Now, you need to look at orbital periods, work your way backwards.
Where it falls apart is you trying to use your first and only defense to disprove any other hypothesis. You rent there yet - you need to be proving your hypothesis with as much data as you can muster.
And something tells me these astronomers might have done the science here.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.