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First Evidence of a Planet in Another Galaxy
- tedd4u 6y agoGalaxy M51 is 23 _million_ light years away. Incredible science! And it sounds like they will be able to use this Chandra data backlog to find more.
- sp332 6y agowhy is it named M51-ULS-1b instead of -1a? Did they pick one of the binary stars to be -1 and the other is -1a, so this planet is -1b?
- tedd4u 6y agoNot sure. I think with the Gliese bodies, the letters were assigned in chronological order of discovery. I guess that makes sense since we could later find other bodies in between and not want to rename everything. https://en.wikipedia.org/wiki/Gliese_581_planetary_system https://en.wikipedia.org/wiki/Gliese_581_planetary_system
- tomr_stargazer 6y agoThat's the naming convention for exoplanets. It descends from the naming conventions for multiple star systems defined by the International Astronomical Union [0], in which the brightest (and usually gravitationally dominant) member of a multiple system receives designation "A", the second-brightest gets "B", and so on. Note the capitals. Planets, being considered a lower-mass extension of stars, get lower-case letters accordingly; so the first planet gets "b", the next planet gets "c" and so on. There is no lowercase "a" in a star-planet system. (I guess you might have that if you found binary planets without a star system; that would be very unusual). Source: my PhD in astrophysics, and: [0] https://en.wikipedia.org/wiki/Exoplanet_naming_convention https://en.wikipedia.org/wiki/Exoplanet_naming_convention
- sp332 6y agoSo in this case the binary system together is 1A? Or is the brighter star 1A, the planet is 1b, and the black hole is 1C because it's darker?
- deleted 6y ago[deleted]
- tomr_stargazer 6y agoI had to look at the paper itself to figure this out, but - in this paper, they designate the binary (star + stellar remnant) together as M51-ULS-1, and the planet actually orbits the two members together (a so-called circumbinary planet [0]). The logic of the nomenclature system actually breaks down in such cases - here's a quote from the Wikipedia article on naming conventions [1] stating as much: 'According to Hessman et al., the implicit system for exoplanet names "utterly failed with the discovery of circumbinary planets", and they state that it is unhelpful. ' So, yeah, take that for what you will. [0] https://en.wikipedia.org/wiki/Circumbinary_planet https://en.wikipedia.org/wiki/Circumbinary_planet [1] https://en.wikipedia.org/wiki/Exoplanet_naming_convention#Circumbinary_planets_and_2010_proposal https://en.wikipedia.org/wiki/Exoplanet_naming_convention#Ci...
- walrus01 6y agoSomething interesting I came across a few weeks back, the many possible methods of detecting exoplanets. https://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets https://en.wikipedia.org/wiki/Methods_of_detecting_exoplanet...
- elihu 6y ago> The planet’s host binary system consists of a neutron star or black hole which is devouring a massive nearby star at a huge rate. The infall of stardust releases huge amounts of energy, making this system one of brightest sources of X-rays in the entire Whirlpool Galaxy. Indeed, its X-ray luminosity is roughly a million times brighter than the entire output of the Sun at all wavelengths. Wow. That's hard to even imagine.
- fsckboy 6y agoit's incredible to me that just less than 100 years ago, we did not even know that there were other galaxies.
- crispyporkbites 6y agoWhat will we know in 100 years from now?
- marricks 6y agoprobably not much as most species alive today will be extinct and there's no reason to think we wouldn't be one of the
- KronisLV 6y agoA possible reason for this cynicism is the fact that we're currently in the middle of the Holocene extinction[0]: > The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background rates. Another thing that's interesting and worrying is the fact that wild animals take up only 4% of the biomass of mammals, 60% being livestock and 36% being humans. [0] https://en.wikipedia.org/wiki/Holocene_extinction https://en.wikipedia.org/wiki/Holocene_extinction
- ehnto 6y agoPlaying devils advocate partly just to make myself feel less depressed about that, but would it not be fair to say that humans have exploded in number, along with livestock, which makes that a somewhat misleading statistic? Even if there was no wild animal extinctions, you would expect humans and livestock to have dominated the percentages simply from growth alone.
- KronisLV 6y agoThe article itself and the referenced sources go into more detail about the species that have gone extinct and the probable causes for that, human behaviour being suspect (habitat destruction, overexploitation, agriculture, climate change; though things such as disease are also mentioned). As for the estimated numbers, at least one such study[0][1] is mentioned: > A 2018 study published in PNAS found that since the dawn of human civilization, 83% of wild mammals, 80% of marine mammals, 50% of plants and 15% of fish have vanished. As for the biomass distribution percentages, you might as well be right! Fig. 1. in the linked study really puts things into perspective, though, animal life being pretty miniscule in the grand scale of things, when compared to plants, bacteria and other types of biomass, which is quite interesting! Growing up, i never saw estimates such as these, which really make me conscious of just how big of an impact humans (and their lifestyle choices, such as the demand for meat) could have on other species and the ecosystems as a whole, hence me mentioning it as something interesting. [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6016768/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6016768/ [1] https://www.theguardian.com/environment/2018/may/21/human-race-just-001-of-all-life-but-has-destroyed-over-80-of-wild-mammals-study https://www.theguardian.com/environment/2018/may/21/human-ra...
- Teichopsia 6y agoLayman here. This is the first I'm hearing that - it is the first time we detect a planet outside our galaxy. Can someone remind me how it comes to pass that there are people in the scientific community who believe we are the only "intelligent" life form? (I know there are a few theories that explain why there aren't any, whose names escape me at the moment) It boggles my mind.
- ajkjk 6y agoThe idea that we are, or are not, the only intelligent life form is an opinion, not a scientific theory in the formal sense of the word -- there is no evidence either way. People's opinions on it are just that, opinions, and scientists can be wrong or biased like anyone else. Statistical arguments, such as the Drake equation, strongly suggest that there is other life. The Anthropic Principle and the 'Great Filter' idea suggest reasons why there might not be. (https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter)
- enkid 6y agoDoes the Drake equation really strongly suggest there is other life? It seems to me there are still so many unknown variables that we can't make that determination at this point. Sure, some people have some intuition about it, but intuition is often (normally...?) wrong.
- the8472 6y agohttps://arxiv.org/abs/1806.02404 https://arxiv.org/abs/1806.02404
- enkid 6y agoLooks like an interesting paper. In fact, it looks like it's saying basically the same thing I'm saying, we really don't know enough to make assertions about the likelihood of finding intelligent life at this point.
- 6y ago
- anti-shill 6y agothat site is paywalled for me and no doubt for others...here is a non paywalled link: https://phys.org/news/2020-09-candidate-extragalactic-planet.html https://phys.org/news/2020-09-candidate-extragalactic-planet...
- throwawaybutwhy 6y agoWhy don't you link to the original preprint [0]? phys.org and its paywalled brethren are all too often touted on HN to waste time on sci-pop. The paper has lots of pictures. [0] https://arxiv.org/pdf/2009.08987.pdf https://arxiv.org/pdf/2009.08987.pdf
- ajnin 6y agoFrom the picture it looks like we're seeing M51 from the "top", does that mean that the planet is orbiting the star system at a right angle from the galaxy plane? Isn't that unusual?
- dexwiz 6y agoI’m pretty sure our system is like this. https://www.forbes.com/sites/startswithabang/2018/08/30/our-motion-through-space-isnt-a-vortex-but-something-far-more-interesting/ https://www.forbes.com/sites/startswithabang/2018/08/30/our-...
- cgriswald 6y agoNo, it’s not unusual. Stars form from clouds of gas and dust collapsing chaotically under their own gravity. It’s the net angular momentum of the cloud that determines the spin and ecliptic of the star system.
- andreygrehov 6y agoHow do we "see" objects so far away from Earth? Are we somehow fetching the light? And if yes, if it's 23 million light years way from us, is it possible that the planet no longer exist at all?
- pier25 6y agoThe Earth is more than 4 billion years old so 23 million years doesn't seem like much.
- alextheparrot 6y agoThey were looking for eclipses - when something blocks the signal they’re observing. In this case, they noticed the X-rays they were looking at were blocked for a few hours. There’s more to it, but the article actually does a good job of explaining it all. There’s not really any way for us to prove if it exists or not today, that information is still quite far away. The best we can do is try to understand the system and make predictions about that.
- notRobot 6y ago> if it's 23 million light years way from us, is it possible that the planet no longer exist at all? Yes, in the same way that if the sun were to suddenly go out, we wouldn't find out for eight minutes (the time that it takes for light from the sun to reach the earth).
- robot 6y agoWhat! How is it that there is yet no evidence that there is a planet in another galaxy?
- wavefunction 6y agoIt's been very difficult to gather the evidence until now? Given the astronomical distances involved and our technological progress?
- dylan604 6y agoNo joke. Up until just a few years ago, we thought Pluto was a planet. Apparently, we can't even decide what a planet is. We also can't even find Planet X in our own solar system. We can find planet in other galaxies, but not our own solar system. This is what passes for science these days? Sheesh! /s
- wavefunction 6y agoPluto is just a matter of semantics. Planet X is merely fantasy at this point.
- garmaine 6y agoDepends on what you mean by Planet X. There's a legit search for another large ice giant in the far reaches of the outer solar system. https://solarsystem.nasa.gov/planets/hypothetical-planet-x/in-depth/ https://solarsystem.nasa.gov/planets/hypothetical-planet-x/i...
- agustif 6y agoNibiru?
- NikolaeVarius 6y agoDetecting planets is hard, even within our own galaxy.
- wgx 6y agoI am very interested in moving there.
- deleted 6y ago[deleted]
- stall84 6y agoAnyone else realize how random it is to have a (potential) planet orbit a black hole in such a specific way that it eclipses it ...> when viewed from fkn Earth.. 20 something million light years away?? lol . nuts Same kinda 'randomness' provides for near-perfect (100%) solar-eclipses from Earth's surface .. Meaning if the Moon orbited any further or closer... it would not have the angular diameter from E's surface to perfectly block-out the angular diameter of the sun as viewed from Earth
- TheOtherHobbes 6y agoI'm not sure the first is all that random. There seem to be a lot of planets and black holes likely aren't all that rare. The second is a stupendous coincidence, and if the Earth ever becomes part of a galactic civilisation we'll have a very impressive draw for alien tourists. Of course it might also be a business card left by the entities that engineered this reality but... probably not.
- saagarjha 6y agoSadly this particular tourist attraction will only be interesting for the next couple hundred million years, after which the moon will drift away too far to make it work anymore :(
- jahnu 6y agoDoesn't that suggest that lots of other moons spend some period of their lifetime in this perfect eclipse zone?
- em3rgent0rdr 6y ago(some very large number of stars) * (some rare possibility for each star) => a potentially non-too-rare number.
- dash2 6y agoBut it's still a huge coincidence for us. If (if!) there are millions of civilizations in the galaxy, presumably only a very few experience total eclipses.
- SubiculumCode 6y agoI am no astronomer, but I find this inconceivable.
- tibbydudeza 6y agoKind of depressing to realize we will never leave our own solar system ... more likely we are going to end ourselves as a species than taking that great leap.
- gravelc 6y agoWe've not proven very good at ending ourselves as a species in the past. Quite the opposite. Not sure where the pessimism is coming from.
- deleted 6y ago[deleted]
- mellosouls 6y agoThe species has barely existed for the blink of an eye in evolutionary terms so there's not much past in that regard. On our own timescale terms we have a rare tendency to group together for intra species battles, and a unique tendency to do that with groups numbering millions. We have an evolutionarily unprecedented and unmatched phenomenon, advanced intelligence, which we employ in scaling the destruction in those battles, to the point we now have the ability to cause catastrophic, possibly existential damage to our species, at least as a civilisation wherein this discussion makes sense; let alone the collateral damage to our environment and co-habitees. That's just the war stuff. The peaceful things we do are too depressing to mention.
- deleted 6y ago[deleted]
- Retric 6y agoHumans have had advanced intelligence across evolutionary timescales because that’s how long it took to evolve. Handmade stone tools are dated all the way back to 3.3 million years, with other examples at 2.8 million years.
- IkmoIkmo 6y agoSource of pessimism? For example: https://en.wikipedia.org/wiki/List_of_nuclear_close_calls https://en.wikipedia.org/wiki/List_of_nuclear_close_calls Assign a non-zero probability that it'll actually go wrong, then extrapolate 10.000 years into the future. The odds aren't necessarily in our favour. And that's just one of many risks out there, over the course of a blink of an eye in the history of the universe/galaxy/earth/humanity.
- sova 6y ago"pics or it didn't happen" ... they even mention awesome x-ray images of the discovery and the whole article is text -- missed opportunity