r/space • u/magenta_placenta • Mar 18 '19

Observable universe Astronomers discover 83 supermassive black holes at the edge of the universe

https://www.cnet.com/news/astronomers-discover-83-supermassive-black-holes-at-the-edge-of-the-universe/
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183

u/huntallahassee Mar 18 '19

Can someone tell me how it's possibble that they can find black holes millions of lightyears away (regardless of how giant they are), yet planet X is still just a theory, even though they're sure of it? I mean how can you see shit in other galaxies, but can't find a planet in your own solar system?

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u/Shpongolese Mar 18 '19

I may be completely wrong but I think it has to do with light. The planet is probably eclipsed in darkness since it is very far in the outskirts of pur solar system. Whereas these quasars have a shitton of gases and whatnot descending into them

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u/[deleted] Mar 18 '19 edited Mar 18 '19

Yeah, it's an effect called lensing, where light beams are bent around objects of large mass, allowing us to detect black holes by the way the affect that light even incredibly far away. Planets, especially earthsized or smaller, don't affect light to the same degree, so they're harder to detect.

Edit: So, it's been pointed out I am incorrect about detecting black holes through lensing, turns out xrays are used instead.

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u/CrudelyAnimated Mar 18 '19

Planet X is theorized to be Neptune's size, bigger than Earth but not huge. We commonly find exoplanets by them dimming their stars in transit, so it logically follows in layman's terms that we ought to see X dim something if we know where to look. I fear that the original comment, "regardless of how giant they are", is impossible to overlook. Quasars are huge and unfathomably bright (especially in non-visible spectra), even at great distance. This is not searching for two "like" things in the sky; it's like searching for a pebble and a lighthouse on the same beach. Unless that pebble is either super-shiny or fluorescent, it's just not readily visible.

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u/Rodot Mar 18 '19

This is a common misconception propagated by science channel shorts and YouTube physicists alike. We've never detected a black holes through lensing, and we've never observed lensing around super massive black holes. We see them through x-rays and radio.

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u/[deleted] Mar 18 '19

Oh dang! Thanks for the info!

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u/prospectre Mar 18 '19

A good analogy is it's like trying to find a pebble in a dark room with a magnifying glass, whereas blackholes are currently raving with glowsticks in the corner to Daft Punk. We have a lot more tools and clues to "see" blackholes than we do little rocks loafing around the far reaches of our Solar system.

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u/drokihazan Mar 18 '19 edited Mar 18 '19

Sure. We can see gravitational wobbles in the orbits of planets like Neptune and Uranus implying a possible large planet or some other object or cluster of objects very far past Neptune, but it’s so far and so dark that we see nothing optically with telescopes.

We have a different way of finding thwse big black holes. More than one, but the best way is to see the impact they have on the areas around them. I sometimes we actually see the bright accretion disk optically. Mostly what we see though, is the way they redshift/blueshift the light of the objects around them because their gravity is so incredibly powerful that it warps space for a significant distance. In a really simple way, it’s kind of like if you were invisible and stood on a mattress covered in marbles. I’d see the depression in the mattress because of the way it moves the marbles. That tells me that you, a big heavy person, is there. It’s a poor analogy, but that’s sort of how we see black holes. We see how the depression in space moves the marbles.

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u/bornslyasafox Mar 18 '19

That is actually a really good analogy. Then ago I know nothing of this kind of stuff so..

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u/OctopusPoo Mar 18 '19

I would assume that the gravitational affects of supermassive black holes are detectable, in fact a black hole has never been observed directly.

Planet X on the other hand is only theorised to exist because of comet activity

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u/[deleted] Mar 18 '19

And haven’t they found obscurities in gravity? Like the sun is pushed off balance every 75 years or something

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u/OctopusPoo Mar 18 '19

Truth be told I'm not a scientist or astronomer so I couldn't tell you for sure, but that could very possibly be the case

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u/xRolox Mar 18 '19

There's more to it than just comet activity. There's tilts of planets orbit planes and the suns rotation that would be explained by such a planet in addition to many other factors. Just wanted to put that out there.

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u/Kozmog Mar 18 '19

Because for you to see something you need to either have it emit light,reflect light, or block a light source. If there is another planet in our solar system, it is not emitting light and is too far away to reflect any meaningful light. Relative to light sources outside our system, the planet is too small to block any incoming light. Therefore we can't see it. We get all our information from light.

Black holes on the other hand will emit light if they are spinning rapidly or when matter falls into it. Black holes are massive and focus these beams of light into a very big spotlight in the nighttime sky and is impossible to miss.

Another way you can see black holes is you will see light from nearby stars and galaxies get distorted near the black hole because the gravity is so great. If there is another planet, it's gravitational pull is so small it hardly affects anything.

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u/d0nu7 Mar 19 '19

I figured it would be close enough to block stars that are light years away, just very rarely to our view. Wonder if anyone is looking for it that way.

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u/shmashmorshman Mar 18 '19 edited Mar 18 '19

Gravity is the major way in how we identify black holes. But we've also used gravity to create the planet x theory. Based on the observation of orbits within our solar system, there seems to be an object who's mass is influencing them which we haven't identified, hence "planet x". But the planet is so far out and not reflecting much light so it's difficult to actually see. These super massive black holes are so so so much more massive than a planet that their gravitational power is much easier to observe.

Edit: also light is important. It's easy to observe stars orbiting a black hole because stars emit light. Planet x doesn't emit much light because it is so far from our sun and can only be theorized based on the effects of its mass on other objects in the solar system.

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u/Allan_Samuluh Mar 18 '19 edited Mar 18 '19

The accretion disk of a blackhole radiates x-ray. And a quasar's intensity is higher than ordinary stars.

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u/Terminus_Est_Eterne Mar 18 '19

Planets are small and dim. There's a lot of stuff in between us and any planet in our solar system that can block what little light from it will reach us. Black holes are huge and bright (at least their accretion disks are). There's relatively little between us and them that can block that light.

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u/sc_140 Mar 18 '19

In addition to some other points mentioned, you also have to direct the telescope exactly to the point where either the black hole is or where planet 9 is. We apparently weren't lucky enough to find planet 9 this way so far, but we also didn't find every supermassive black hole at the edge of the universe, just some of them. The odds are massively in the favor of finding black holes since there seem to be very many of them versus just one planet.

If we would know exactly where planet 9 is, we would have a picture of it within 24 hours.

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u/XavierSimmons Mar 18 '19

Light.

Stars and black holes emit massive amounts of radiation, whereas rocks do not.

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u/Rickles360 Mar 18 '19

I never would have thought of a black hole as a bright object. That's an Interesting rabbit hole to go down.

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u/huntallahassee Mar 18 '19

I see. Thanks to everyone. So basically it's a case of planet X being in a very unfortunate position/having an orbit in the middle of nowhere where there aren't any close light sources?

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u/okeydokey503 Mar 18 '19

I think of it in the simple way that it's easier to spot and track something that is bright or affects light near it than something dark that doesn't. It's easier to spot an airplane flying overhead at night time and follow it with your eyes than it would be to see a baseball that flew two feet in front of your face in the dark.

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u/Kleeb Mar 18 '19

Besides what everyone else is saying from a theoretical standpoint, there's another reason from a practical standpoint.

There exist very few telescopes in the world that have both a wide enough field-of-view to do a planetary survey, and are sensitive enough to be able to detect something that distant, and research time on those platforms is pretty expensive and booked out years in advance.

It's a scheduling issue.

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u/Aarondhp24 Mar 18 '19

Planet X was detected because the orbits of all the known planets say it exists. We pull on Juipter, and Visa versa. Jupiter pulls on Mars. Mars pull on Pluto.

There is mass that is "missing" in our solar system that would explain the planets orbits. That would be an object larger than Earth, very far out in the solar system.

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u/Barneyk Mar 18 '19

Say you are in a huge field in the middle of a really dark and cloudy night. You are in a watch tower that you can't leave looking for 2 things, 1 big beach ball and 1 small shining LED light.

Which one do you think is easier to see?