Sagittarius A East, an enormous oval shell of gas near our galaxy’s center, has puzzled astronomers since its discovery in 1966. At some 30 light-years across, Sgr A East is about the size of most supernova remnants. Such remnants are produced when an exploding star releases high- energy gases that collide with surrounding interstellar gases, usually with a force of about 1034 tons of TNT. The force of such an enormous explosion typically thrusts gas outward, carving out an immense spherical bubble of empty space. In the more dense medium near the Milky Way’s center, however, a much larger explosion--10 to 100 times a typical supernova--would be necessary to displace the same amount of gas. A single exploding star could not have unleashed the energy needed to create Sgr A East. So how did it form?
Astronomer Alexei Khokhlov at the University of Texas and physicist Fulvio Melia at the ...
