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栗まんじゅう問題 - アンサイクロペディア
"...であるが、一見してわかる通り、シュヴァルツシルト半径は質量に比例し、質量は半径の3乗に比例するため、シュヴァルツシルト半径は栗まんじゅう球の半径の3乗に比例する。言い換えれば、初期のうちはごく小さかったシュヴァルツシルト半径が、分裂が進行するにつれて急激に大きくなり、いずれは栗まんじゅう球自身の半径を追い越してしまうことになる。その結果、栗まんじゅう球はブラックホールとなる。

ひとたびブラックホールとなり、すべての栗まんじゅうが事象の地平面の内側に入ってしまった場合、それらは我々の観測可能な宇宙から切り離される。この状態になれば、事象の地平面の外側から見る限り、分裂が停止したものとして扱える。 "
astrophysics  food  relativity_theory 
20 hours ago by incep
Trouble Detected in Infamous Dark Matter Signal | Quanta Magazine
New results from a decades-old experiment were initially touted as further evidence for dark matter. But independent scientists have cast serious doubt on that claim, leaving most everyone puzzled.
articles  cosmology  astrophysics 
3 days ago by gmisra
Hubble Telescope Reveals Source of Gas Streaming Into Milky Way | Simons Foundation
The Leading Arm of the Magellanic Stream originates primarily from a nearby dwarf galaxy called the Small Magellanic Cloud
articles  space  astrophysics 
15 days ago by gmisra
Dozen black holes found at galactic centre - BBC News
A dozen black holes may lie at the centre of our galaxy, the Milky Way, researchers have said.
articles  astrophysics 
18 days ago by gmisra
A Victory for Dark Matter in a Galaxy Without Any | Quanta Magazine
Paradoxically, a small galaxy that seems to contain none of the invisible stuff known as “dark matter” may help prove that it exists.
articles  astronomy  astrophysics 
25 days ago by gmisra
Whisper From the First Stars Sets Off Loud Dark Matter Debate | Quanta Magazine
A surprise discovery announced a month ago suggested that the early universe looked very different than previously believed. Initial theories that the discrepancy was due to dark matter have come under fire.
articles  cosmology  astrophysics 
25 days ago by gmisra
Dragonfly - Dunlap Institute
Dragonfly is an innovative, multi-lens array designed for ultra-low surface brightness astronomy at visible wavelengths. Commissioned in 2013 with only three lenses, the array is growing in size and proving capable of detecting extremely faint, complex structure around galaxies. The most recent upgrade—completed in 2016—saw Dragonfly grow to 48 lenses in two clusters.

Dragonfly is designed to reveal the faint structure by greatly reducing scattered light and internal reflections within its optics. It achieves this using commercially available Canon 400mm lenses with unprecedented nano-fabricated coatings with sub-wavelength structure on optical glasses.
astrophysics  telescopes  engineering  science  reference 
27 days ago by kmt
Whisper From the First Stars Sets Off Loud Dark Matter Debate | Quanta Magazine
A surprise discovery announced a month ago suggested that the early universe looked very different than previously believed. Early theories that the discrepancy
darkmatter  cosmology  astrophysics 
28 days ago by geetarista
Black Hole Echoes Would Reveal Break With Einstein’s Theory | Quanta Magazine
Gravitational waves have opened up new ways to test the properties of black holes — and Einstein’s theory of gravity along with them.
articles  astrophysics 
4 weeks ago by gmisra
To Test Einstein’s Equations, Poke a Black Hole | Quanta Magazine
Two teams of researchers have made significant progress toward proving the black hole stability conjecture, a critical mathematical test of Einstein’s theory of general relativity.
articles  astrophysics 
6 weeks ago by gmisra

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