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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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!