Astronomers have long known that dark dust lanes cross its face--but ellipticals aren't supposed to have any
interstellar matter to speak of.
Interstellar matter dims the group by about 13 magnitudes at visible wavelengths--a factor of about 150,000.
They show delicate tendrils of dark
interstellar matter lining the nebula's northwestern quadrant.
Airplane-gathered particles, on the other hand, are turning out to contain pristine
interstellar matter. Scott Messenger and his colleagues at Washington University in St.
A cloud of
interstellar matter falls together under its own gravity; the cloud shrinks to form a spinning star surrounded by a rotating disk of gas and dust; dust in the disk starts sticking together in clumps; the clumps grow big enough to start collecting matter faster by gravity; this continues until all the dust and gas are incorporated into planets or blown away.
It amounts to only about 1 percent of
interstellar matter; the rest is gas.
They may be close enough together that a near-collision stirred up
interstellar matter in both galaxies, causing some of it to fall toward the black holes and light up brilliantly.