4 ms·
Very good question. As a non-astronomer, my guess is that we don’t observe a lot of transient black outs for example of the milky way. Which would happen if the
by ano-ther 3y ago
Very good question. As a non-astronomer, my guess is that we don’t observe a lot of transient black outs for example of the milky way. Which would happen if there’s a lot of these around.
That gives you an upper bound of how many objects like that exist.
- perihelions 3y agoMicrolensing events! (to be slightly more precise) https://en.wikipedia.org/wiki/Rogue_planet#Microlensing https://en.wikipedia.org/wiki/Rogue_planet#Microlensing - "They found 474 incidents of microlensing, ten of which were brief enough to be planets of around Jupiter's size with no associated star in the immediate vicinity. The researchers estimated from their observations that there are nearly two Jupiter-mass rogue planets for every star in the Milky Way.[26][27][28] One study suggested a much larger number, up to 100,000 times more rogue planets than stars in the Milky Way, though this study encompassed hypothetical objects much smaller than Jupiter.[29]"
- lamontcg 3y agoAnd "MACHOs": https://en.wikipedia.org/wiki/Massive_compact_halo_object https://en.wikipedia.org/wiki/Massive_compact_halo_object In the 1990s I went to a talk which suggested that "WIMPs" (Weakly Interacting Massive Particles aka supersymmetric particles that would give rise to dark matter) was an acronym for "Well It Might be Physics" while MACHOs was "Maybe Astrophysics Can Help Out". The upper bound on MACHOs has looong since eliminated them as the explanation for all of dark matter though...
- ryandrake 3y ago...or an upper bound of how big they might be. For all we know, the galaxy might be full of really dark bowling ball sized objects. We'd have no way of observing them, right?
- mike_hock 3y agoWhat if dark matter is primordial bowling balls!
- semi-extrinsic 3y agoSo these are called "snowballs" and are excluded as dark matter candidates because we would then see a much larger number of extra-solar asteroids/meteorites. Cf. e.g. section 2 of the reference below. https://web.archive.org/web/20180723032406/http://iopscience.iop.org/article/10.1086/307071/pdf https://web.archive.org/web/20180723032406/http://iopscience...
- jiggawatts 3y agoI love how every time someone comes up with some random notion, a scientist can point at a chart and say “we’ve thought of that already and excluded it with experiment CoolName.”
- throwawaymaths 3y agoReally dark bowling balls would still exhibit blackbody radiation