Re:Astronomers uncover largest group of rogue planets yet
by TaylorAlexander on Saturday January 01, 2022 @04:33PM
(#29763064)
I’m imagining at least one rogue planet out there (they said they could be billions) was happily orbiting a star for billions of years, life formed, even relatively intelligent life, and then another rogue planet fell in to the solar system and passed right by the first planet in such a way as to eject it from the solar system without hitting it, and all this life on the planet suddenly loses daylight as their planet flies off in to deep space. And now their ancient civilization is frozen in time, adrift in deep space.
Re:Astronomers uncover largest group of rogue planets yet
by akiselev on Saturday January 01, 2022 @03:14PM
(#29762200)
I'm kind of burned out on exoplanet discoveries since they're a dime a dozen nowadays but this title caught my eye because I've been rewatching Star Trek DS9 recently. The antagonist in the latter half of the series is the Dominion empire which is unilaterally controlled by a race of hivemind-y shapeshifters called the Changelings. The only time we get to see most of their species is on their home world, a rogue planet somewhere in the gamma quadrant.
I've been fascinated by the idea of detecting rogue planets ever since and it's incredible they found so many. Unfortunately, it looks like their detection method might not be useful for older (billion+) or rocky planets (from the footnote):
> The exact number of rogue planets found by the team is hard to pin down because the observations don't allow the researchers to measure the masses of the probed objects. Objects with masses higher than about 13 times the mass of Jupiter are most likely not planets, so they cannot be included in the count. However, since the team didn't have values for the mass, they had to rely on studying the planets' brightness to provide an upper limit to the number of rogue planets observed. The brightness is, in turn, related to the age of the planets themselves, as the older the planet, the longer it has been cooling down and reducing in brightness. If the studied region is old, then the brightest objects in the sample are likely above 13 Jupiter masses, and below if the region is on the younger side. Given the uncertainty in the age of the study region, this method gives a rogue planet count of between 70 and 170.
That said, this is exciting news!
> The study suggests there could be many more of these elusive, starless planets that we have yet to discover. "There could be several billions of these free-floating giant planets roaming freely in the Milky Way without a host star," Bouy explains.
Re:Astronomers uncover largest group of rogue planets yet
by almostdeadguy on Saturday January 01, 2022 @08:07PM
(#29764662)
Only tangentially related, but Melancholia is a beautiful (and uh melancholic) movie about a rogue planet that perfectly captures a prevailing mood about our present moment: https://en.wikipedia.org/wiki/Melancholia_(2011_film)
Not that we ever actually have to worry about a collision with a rogue planet.
Re:Astronomers uncover largest group of rogue planets yet
by addaon on Saturday January 01, 2022 @03:01PM
(#29762068)
Do these form like stars (as the primary mass in a cloud collapse?), or do they form like solar planets (secondary masses around a star) and get ejected? If the former, is there any mechanism for ejecting light elements to produce something like a terrestrial planet or are these inherently gas planets?
Re:Astronomers uncover largest group of rogue planets yet
by stevenpetryk on Saturday January 01, 2022 @03:12PM
(#29762185)
From the article:
> Some scientists believe rogue planets can form from the collapse of a gas cloud that is too small to lead to the formation of a star, or that they could have been kicked out from their parent system. But which mechanism is more likely remains unknown.
Re:Astronomers uncover largest group of rogue planets yet
by addaon on Saturday January 01, 2022 @03:16PM
(#29762221)
Not sure how I missed this, thanks!
Am I correct that the latter mechanism can lead to a wider variety of planet compositions, since you have the wind off the forming star to blow off lightweight layers depending on how close to the star formation happens?
Re:Astronomers uncover largest group of rogue planets yet
by JoeAltmaier on Saturday January 01, 2022 @05:40PM
(#29763618)
I imagine most planets might be rogue. Stellar formation is incredibly energetic and violent. That any planets remain in stable arrangements is amazing.
Re:Astronomers uncover largest group of rogue planets yet
by ineedasername on Saturday January 01, 2022 @10:48PM
(#29765624)
I wasn't aware that planets could have traditional RPG roles. Whatever class Earth chose, it really needs to roll a 20 right now.
More in topic, I really like the idea of random planets floating the void on their own. I'd be really curious about they have a unique composition. Although the lack of an external energy source probably means there wouldn't be much potential for activity.
full text: https://www.gutenberg.org/ebooks/51461
[1] https://xeelee.fandom.com/wiki/Silver_Ghosts
[2] Best read in the form of summaries and compilations of world-building backstory.
https://en.wikipedia.org/wiki/Worlds_in_Collision
It may not be very good as science fiction, but it's an interesting historical/social phenomenon.
https://www.youtube.com/watch?v=gLZJlf5rHVs
[0] https://en.wikipedia.org/wiki/Frostpunk
I've been fascinated by the idea of detecting rogue planets ever since and it's incredible they found so many. Unfortunately, it looks like their detection method might not be useful for older (billion+) or rocky planets (from the footnote):
> The exact number of rogue planets found by the team is hard to pin down because the observations don't allow the researchers to measure the masses of the probed objects. Objects with masses higher than about 13 times the mass of Jupiter are most likely not planets, so they cannot be included in the count. However, since the team didn't have values for the mass, they had to rely on studying the planets' brightness to provide an upper limit to the number of rogue planets observed. The brightness is, in turn, related to the age of the planets themselves, as the older the planet, the longer it has been cooling down and reducing in brightness. If the studied region is old, then the brightest objects in the sample are likely above 13 Jupiter masses, and below if the region is on the younger side. Given the uncertainty in the age of the study region, this method gives a rogue planet count of between 70 and 170.
That said, this is exciting news!
> The study suggests there could be many more of these elusive, starless planets that we have yet to discover. "There could be several billions of these free-floating giant planets roaming freely in the Milky Way without a host star," Bouy explains.
13 Mj is on the low side of the definition. It's not a definitive number and goes as high as 80 Mj, depending who you ask.
These numbers depend on a lot of details of stellar atmospheres.
I took a graduate-level Stellar Atmospheres class from S. Kumar, who first theorized about this class of not-quite-star.
Not that we ever actually have to worry about a collision with a rogue planet.
> Some scientists believe rogue planets can form from the collapse of a gas cloud that is too small to lead to the formation of a star, or that they could have been kicked out from their parent system. But which mechanism is more likely remains unknown.
Am I correct that the latter mechanism can lead to a wider variety of planet compositions, since you have the wind off the forming star to blow off lightweight layers depending on how close to the star formation happens?
https://en.wikipedia.org/wiki/Rogues%27_gallery
More in topic, I really like the idea of random planets floating the void on their own. I'd be really curious about they have a unique composition. Although the lack of an external energy source probably means there wouldn't be much potential for activity.