how close is the nearist black hole in light year
- Thread starter drychlick
- Start date
The companion of V4641 Sgr at 1600 ly is a black hole according to this article:
http://www.nrao.edu/pr/2000/v4641/
Perhaps they've found a closer one since 2000.
The nearest neuton star is Geminga at 330 ly, although some sources state 552 ly:
http://www.daviddarling.info/encyclopedia/G/Geminga.html
Again this may be out of date.
http://www.nrao.edu/pr/2000/v4641/
Perhaps they've found a closer one since 2000.
The nearest neuton star is Geminga at 330 ly, although some sources state 552 ly:
http://www.daviddarling.info/encyclopedia/G/Geminga.html
Again this may be out of date.
Those are just the closest ones we know of. A black hole, as its name suggests, is black. If it's paired with a star and is drawing in matter, then the heating of the accretion disk gives off detectable gamma rays. But contrary to the portrayals in fiction that have been ubiquitous since Disney's The Black Hole, standalone black holes wouldn't have accretion disks, since they're in the middle of the vacuum of space and so don't have anything around them to accrete. They'd just be dark and non-radiating, and the only way to detect one would be by its gravity lensing of the light from stars behind it.
Similarly with neutron stars -- many of them radiate lots of energy (pulsars), but the majority may be very dim and hard to detect. Heck, there are red dwarf stars within ten parsecs that we've only recently discovered and probably more we haven't found yet, and there's a good chance there may be brown dwarfs out there even closer than Alpha Centauri. So we can't really say where the closest neutron star is yet, let alone black holes.
Similarly with neutron stars -- many of them radiate lots of energy (pulsars), but the majority may be very dim and hard to detect. Heck, there are red dwarf stars within ten parsecs that we've only recently discovered and probably more we haven't found yet, and there's a good chance there may be brown dwarfs out there even closer than Alpha Centauri. So we can't really say where the closest neutron star is yet, let alone black holes.
