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An Earth-sized rogue planet discovered in the Milky Way
- bookofjoe 6y agohttps://news.ycombinator.com/item?id=24946459 https://news.ycombinator.com/item?id=24946459
- 88840-8855 6y agoEarth-sized rogue planet number 3592 discovered. Wake me up when there is something exciting.
- lifeisstillgood 6y agoIt's a planet somewhere else in the galaxy. There are still people alive today who were born into a world where we thought there was just one galaxy, and only nine planets anywhere. We are like ants floating on a stick in the pacific, inferring New York's street plan from air currents. This shit is awesome. I don't believe you really are bored by this. Try affecting interest and enthusiasm - it generally works a lot better in life.
- nxmnxm99 6y agoMore like ants in the pacific realizing there’s another giant rock in the horizon they’ll probably never reach, and likely has nothing worth looking at even if they do reach
- fuhrysteve 6y agoIf it's so uninteresting to you, why participate in the discussion?
- nxmnxm99 6y agoTo comment on how uninteresting it is, obviously?
- mturmon 6y agoWe used to think the composition of the Sun would never be known because there was no way to take a sample. Now, because of spectroscopy, we know the composition of the Sun and all the planets. We’re pretty clever when we put our minds to something.
- lifeisstillgood 6y agoI don't understand that attitude - truly. Yes humanity might never get to another solar system, but then I am never going to walk on the Moon - it still looks beautiful in the night sky and the dream of getting there drove half of all science for centuries. We can make this ant colony better today.
- nxmnxm99 6y agoHow does investing tons of valuable money and man hours into investigating said probably pointless rock make our any colony better today?
- lifeisstillgood 6y ago>>> A rat done bit my sister Nell. (with Whitey on the moon) Her face and arms began to swell. (and Whitey's on the moon) Gil Scott-Heron is right - but also not. I was reminded of this watching First Man - and I realised that if 1960s USA had not funded a Moonshot, then would it have looked at itself and said "Hey our police force is used to keep 1/5th of our population in poverty through violence and our financial policies do the same. Let's fix that"? The thing about the space race was not how much money it got but how it was allowed to define problems using measurements to the millimetre and then solve them at the edge of what was technically possible. They were free of politics because no one had ever done it before. But politics is itself how we decide what the problem is. The concept that the US could have spent the moon money on fixing its self is ... a stretch. But to give in to that line of thinking is to abandon all hope. Not spending money on space is not the same as spending it on fixing our deepest problems. Until we can convincingly show we agree on what our problems actually are, I am reluctant to think we can spend billions fixing them. Instead let's fire spaghetti at the walls on local levels - maybe we can find solutions local interventions first.
- nxmnxm99 6y ago> Until we can convincingly show we agree on what our problems actually are, I am reluctant to think we can spend billions fixing them. So instead spend billions staring at dead rocks? Going to the moon had tremendous political and strategic value during wartime - the same conditions don’t exist in the world today.
- microtherion 6y agoIn the sense that it's detection of an object that's hard to detect, of which few are known, and that exists under unusual conditions, it's cool indeed. But from the point of view of people who find planets interesting primarily for their potential to harbor life, I would suspect that rogue planets are particularly inhospitable and thus not all that interesting.
- lifeisstillgood 6y agoBut ... Space 1999!!! :-)
- slg 6y ago>There are still people alive today who were born into a world where we thought there was just one galaxy, and only nine planets anywhere. It might be a pedantic quibble, but you have the timeline of these discoveries a little messed up. There are people alive today who were born in a world in which we thought there was only one galaxy, but they also thought there were only 8 planets at the time. Hubble proved there were other galaxies a few years before Pluto was discovered. You would have to go back to the 1850s to find anyone who thought there were more than 8 planets and only one galaxy. Back then dwarf planets and large asteroids were all categorized as planets which put us at over 20 planets before there was a reclassification.
- markkanof 6y agoAre you sure about this? A google search indicates Pluto was discovered in 1930 and Hubble was launched in 1990.
- slg 6y agoSorry, I could have phrased that better to avoid the confusion. I was talking about Edwin Hubble the person who the telescope is named after. He showed that other galaxies existed in 1925. [1] [1] - https://www.discovermagazine.com/the-sciences/january-1-1925-the-day-we-discovered-the-universe https://www.discovermagazine.com/the-sciences/january-1-1925...
- lifeisstillgood 6y agoFantastic quibble - I stand corrected (I had Hubble in mind but did not know the 20+ planets part.) Perfect pedantry :-)
- slg 6y agoIt is always fun to bring up the 20 planets thing when people complain about Pluto not being a planet anymore. Lots of people have never even heard of fellow dwarf planet Ceres, but it spent almost as long as a full fledged planet as Pluto. The only reason most people defend Pluto's inclusion among planets and not Ceres is because Ceres was recategorized a century before most of us were born. It shows that the primary objection from laypeople is that we don't like when something we were taught as children changes.
- iso947 6y agoI went to Joderell bank (before covid) with my kids, Id been there myself as a kid a few times in the early 90s. We saw the display on exoplanets - it has a counter of the thousands that had been discovered. When I was my kids age that counter was on zero, it’s amazing how much has been done in 30 years.
- simlevesque 6y agoSmallest one ever found.
- HenryKissinger 6y agoHow far is it? The article doesn't say.
- ojnabieoot 6y agoThe distance is unknown[1] and if it were very far away, it actually could be a Jupiter-sized planet - I believe there was other circumstantial evidence that suggested this didn't "move" like a gas giant. I am not sure what a "Gaia proper motion measurement of the source" means [this is from the article] but I am not an astronomer and didn't read the whole article. Keep in mind how they detected this: they looked at the gravitational distortion of light caused by the planet's influence. We are used to seeing this gravitational lensing with black holes, which is visibly obvious even to an untrained human eye. The effect exists for every object with mass, but it's extremely tiny for planet-mass objects. For planet detection without a host star, it is the best measurement we have, but it's very finnicky and doesn't contain very much information compared to spectral analyses, motion around a host star, etc. From that paper's abstract: > Although in practice [rogue planets] do not emit any light, they may be detected using gravitational microlensing via their light-bending gravity. Microlensing events due to terrestrial-mass rogue planets are expected to have extremely small angular Einstein radii (~ 1 µas) and extremely short timescales (~ 0.1 day). Here, we present the discovery of the shortest-timescale microlensing event, OGLE-2016-BLG-1928, identified to date (tE ≈ 0.0288 day = 41.5 min). Thanks to the detection of finite-source effects in the light curve of the event, we were able to measure the angular Einstein radius of the lens θE = 0.842 ± 0.064 µas, making the event the most extreme short-timescale microlens discovered to date. Depending on its unknown distance, the lens may be a Mars- to Earth-mass object, with the former possibility favored by the Gaia proper motion measurement of the source. The planet may be orbiting a star but we rule out the presence of stellar companions up to the projected distance of ∼ 8.0 au from the planet. Our discovery demonstrates that terrestrial-mass free-floating planets can be detected and characterized using microlensing. [1] https://arxiv.org/pdf/2009.12377.pdf https://arxiv.org/pdf/2009.12377.pdf
- azernik 6y agoAFAIU, the star being lensed was within the Milky Way, so they could establish some limits on the size of the lensing planet. The upper size bound in the paper is 2 earth masses. (Jupiter mass does come up, but only in the context of a binary system - when ruling out that this planet is orbiting a star, they can only rule out a parent body larger than a few Jupiter masses.)
- part1of2 6y ago> However, theories of planet formation and evolution predict the existence of free-floating (rogue) planets, gravitationally unattached to any star. What's the theory that predicted this? After billions of years, I would expect all planets be attached (gravitationally) to a star, shouldn't they? > Indeed, a few years ago, Polish astronomers from the OGLE team from the Astronomical Observatory of the University of Warsaw provided the first evidence for the existence of such planets in the Milky Way. Wait. Evidence is not the theory. Did they predict this or discover it?
- ojnabieoot 6y agoI don't quite understand why you're being so pedantic about this. The earliest reference I could find was from 1987, theorizing that proto-planetary objects could be ejected from a planetary disk and that this likely happened in our solar system due to sling-shotting from Jupiter[1]: > After Jupiter had accreted large amounts of nebular gas, it could have gravitationally scattered the planetesimals remaining nearby into orbits which led to escape from the Solar System. But this was purely speculative. It wasn't until many years later that the planet was actually observed. > After billions of years, I would expect all planets be attached (gravitationally) to a star, shouldn't they? I am not sure what you mean by that. All planets are formed in disks surrounding a star (or possibly a brown dwarf); rogue planets are planets that were able to escape the influence of that star. It might take billions of years before they get close enough to another star in the galaxy to fall into its influence. [1] https://ntrs.nasa.gov/citations/19870013947 https://ntrs.nasa.gov/citations/19870013947
- part1of2 6y agoThe comment came off stronger than intended. It sounded like lazy journalism that made a claim, but then used a different conclusion. Thank you fr pointing me to the NASA site. > that were able to escape the influence of that star. What's the mechanism here? Is it something with greater mass that pulled it into an escape?
- Aerroon 6y ago
- deepsun 6y agoCan they compose dark matter?
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- hinkley 6y agoThe matter we can see only accounts for ~4% of the 'stuff' that orbital mechanics says is there, and the other stuff doesn't interact with light (so no clouds) There would have to be 25 times as many rogue planets as the mass of all systems, and most of the mass in a system is in its sun, so 25 Earths, Jupiters and Saturns are barely a blip.
- deepsun 6y ago4% of the 'stuff' is when we're considering dark energy, but I'm talking only about matter here (galaxy scale). There's still more than 5 times more dark matter than any matter we see, though. But I thought if it's extremely hard to detect rogue planets, then what if there's whole bunch of them, like really 6 times more than other matter including stars. And there's no clouds around them for some reason (example reason is that they were expelled from their formation clouds by gravitation dance with other planets there).
- awb 6y agoAmazing discovery! On a related note, it's possible to have rogue solar systems as well: https://medium.com/starts-with-a-bang/ask-ethan-can-stars-escape-from-the-galaxy-with-planets-intact-e8b6f4bf73ef https://medium.com/starts-with-a-bang/ask-ethan-can-stars-es...
- netcan 6y agoIt's fascinating how fascinated we are with categories, typologies and their exceptions. It's like Sapiens crack, especially nerd sapiens. Here is is our linnaean classification of species. Look how these species are breaking the species barrier! Nature, meanwhile, isn't very fussy about the concept of species. It's not even strict about the concept of an organism.. even cells or any of the classifications we use to understand bundles of biology. A planet is a thing that orbits our sun. Hey, exoplanets! A planet is a thing that orbits a star. Hey, rogue planets. Hey, rogue solar system! Meanwhile, the universe isn't all that fussy about solar systems or galaxies.
- simonh 6y agoI think the most interesting stuff is how things work. How do they form, what’s their life cycle, what attributes and effects to they have, etc. But classifying things is useful to understand the processes and attributes they have in common. But yes our classifications are just a map, and we should not confuse the map for the terrain.
- netcan 6y agoCan we avoid confusing map with terrain? Our minds don't seem to naturally make as much of a distinction between abstraction and manifestation as we do.
- colordrops 6y agoWho is "our minds" vs "we"?
- jcims 6y agoThat’s no planet...
- hinkley 6y agoAssuming we never crack FTL travel, I suspect rogue planets/planetoids will be part of our strategy to travel between the stars.
- Aerroon 6y agoFinding and tracking these rogue planets today seems to be a bit like the astronomers of old figuring out the movement of planets in our solar system. It'll probably be very useful in the future. Maybe one day we might even be able to adjust the course of one of them. Related to this, I wonder what the minimum resources a rogue planet has to have for human habitation in the future. Obviously there won't be sunlight, which means that we will have to generate all of our energy in some other way. Nuclear fission? Fusion?
- has2k1 6y agoThere is geothermal energy if it has a molten core.
- pvaldes 6y agoMaybe chemical energy also. Think in a planet with a sea of methane for example.
- m4rtink 6y agoWon't help much if there is not something else to react it with. I guess you could get the hydrogen from it and use it for fusion reactors. Also if you find some water you could split it for oxygen and use methalox rocket propulsion locally.
- hinkley 6y agoMetal and silicon oxides can be cracked for the oxygen, either as a separate process or as part of consuming the methane. That might be enough to keep you from freezing to death. Plants to consume the carbon dioxide, giving you calories and the oxygen back.
- canjobear 6y agoThe Founders
- caryd 6y agoI'm thinking the gravity would be too much, but it could be great for mining machines
- satya71 6y agoI wonder if life would be possible on such a planet. It would need to generate its own heat, much like the earth does in its core. There could be small habitable zone much like the ecosystem near deep sea volcanoes.
- kabacha 6y agoThe instant question this title raises: how hard would it be to move a planet into close orbit of the sun? Weirdly enough I never came up to a similar scenario in countless sci-fi books. I'd imagine it would be so expensive that if we were capable of it we would probably wouldn't need/want it as other alternatives would be much more efficient, right? The thought of designed solar system is interesting - what if we FTL is an unbeatable barrier - we might just be stuck here and populate our system with hundreds of rogue passerby planets!
- peeters 6y agoNapkin math: Earth orbits at ~30 km/s, escape velocity is ~42 km/s. So to get Earth to leave the solar system (the inverse of capturing a planet under the most optimal circumstance), you would need to give it 12 km/s. Earth is ~6 * 10^24 kg, so that represents ~4.3 * 10^32 joules. The sun gives out around 3.8 * 10^26 joules per second (i.e. watts). So with perfect efficiency, working just from conservation of energy, this would require around 13 days of the entire energy output of the sun. Or around a trillion years at Earth's current energy consumption.
- ngold 6y agoNapkin math, my favorite kind of math. Love the days of the sun output part. Sure why not...only 13 days.
- kabacha 6y agoHonestly that doesn't sound so much for a late civilization.
- m4rtink 6y agoYeah, nothing complicated for an advanced Dyson swarm - getting the energy there and propelant (unless you somehow acquired a reactionless drive) would be the main problems.
- maxerickson 6y agoAliens in Ring World do it: https://en.wikipedia.org/wiki/Pierson%27s_Puppeteers#Homeworld.E2.80.94The_Fleet_of_Worlds https://en.wikipedia.org/wiki/Pierson%27s_Puppeteers#Homewor...
- ant6n 6y agoWait a minute, the article says there’s no star within 8 AU? That doesn’t necessarily mean it’s a rogue planet, it could have a host star at 9 AU, the distance of Saturn from the Sun. What an I missing?
- DonCopal 6y agoI didn't read the paper, but if they can measure its orbital eccentricity, they can see if it's gravitationally bound to that star. Like they did with ʻOumuamua.
- blackoil 6y agoKurzesagt has an interesting video on life on rogue planets, https://www.youtube.com/watch?v=M7CkdB5z9PY https://www.youtube.com/watch?v=M7CkdB5z9PY.
- teekert 6y agoCool! For a Nice read on a Roque planet (fiction): https://georgerrmartin.com/grrm_book/dying-of-the-light/ https://georgerrmartin.com/grrm_book/dying-of-the-light/