[HN Gopher] Nasa's Roman Mission Will Hunt for Primordial Black ...
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       Nasa's Roman Mission Will Hunt for Primordial Black Holes
        
       Author : gmays
       Score  : 30 points
       Date   : 2024-05-09 22:33 UTC (1 days ago)
        
 (HTM) web link (www.nasa.gov)
 (TXT) w3m dump (www.nasa.gov)
        
       | api wrote:
       | Primordial black holes are a fascinating topic. One of my
       | favorite hypotheses is that "planet nine," a large possibly 1-5
       | Earth mass planet suggested by some orbital models to exist
       | beyond Neptune and Pluto in the far outer solar system, may be a
       | primordial black hole.
       | 
       | If such a thing existed it'd be a black hole about the size of a
       | billiard ball and would be extremely hard to detect. It would not
       | emit Hawking radiation (Hawking temperature still below the CMB),
       | so the only thing it would emit would be when it encountered
       | something and tore it apart. In that case you'd see X-rays, gamma
       | rays, etc., but maybe only briefly. Only way to find it might be
       | to model orbits accurately enough to predict its position and
       | then look for gravitational lensing.
       | 
       | If this companion object did exist it'd be a gigantic discovery
       | of huge importance. It'd be within reach of probes, making it
       | possible to study and even do experiments on to investigate
       | things like quantum gravity. It could also be used in tight
       | gravity assist flybys to accelerate probes to incredible
       | velocities, maybe making interstellar probes a lot more
       | practical. It'd be our very own way to yeet stuff to the stars,
       | assuming these things could withstand insane g-forces (so
       | probably not humans unfortunately).
        
         | ryandrake wrote:
         | > It could also be used in tight gravity assist flybys to
         | accelerate probes to incredible velocities, maybe making
         | interstellar probes a lot more practical.
         | 
         | Would 1-5 earth masses really provide enough of a yeet to
         | appreciably affect the speed of a probe? Jupiter is about 300+
         | earth masses and we're not flinging probes out to stars using
         | him.
        
           | dooglius wrote:
           | We did, Voyager 1 and 2 used Jupiter to get out of the solar
           | system
        
           | bigyikes wrote:
           | You can get a lot closer to the center of mass of the black
           | hole, which should drastically increase acceleration since it
           | falls off with distance squared.
        
       | breckenedge wrote:
       | I really want primordial black holes to turn out to be the
       | missing antimatter from the Big Bang, but I don't think that
       | could ever be tested. And of course a mechanism for this would
       | probably need new physics since antimatter interacts the same as
       | normal matter wrt gravity.
        
         | stainablesteel wrote:
         | it sounds a lot like it now that i read this, large dispersed
         | amounts of antimatter that apparently doesn't give off light
         | yet has massive gravitational pull
        
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       (page generated 2024-05-10 23:00 UTC)