|
Credit & Copyright: Fabio Governato
et al.
(U. Washington),
N-Body Shop,
NASA Advanced Supercomputing
Explanation:
How do galaxies like our Milky Way form?
Since our universe moves too slowly to watch, faster-moving computer simulations
are created to help find out.
Green depicts (mostly) hydrogen gas in the
above movie, while time
is shown in billions of years since the Big Bang on the lower right.
Pervasive
dark
matter
is present but not shown.
As the simulation
begins, ambient gas falls into and accumulates in regions of relatively high gravity.
Soon numerous proto-galaxies form, spin, and begin to
merge.
After about four billion years, a well-defined center materializes that dominates
a region about 100,000
light-years
across and starts looking like a modern disk
galaxy.
After a few billion more years, however, this early galaxy collides with another,
all while
streams of gas from other mergers rain down on this
strange and fascinating cosmic dance.
As the
simulation
reaches half the current age of the universe, a single larger disk develops.
Even so, gas blobs -- some representing
small satellite galaxies
-- fall into and become absorbed by the rotating galaxy as the present epoch is reached
and the movie ends.
For our
Milky Way Galaxy,
however, big mergers may not be over -- recent evidence indicates that our large
spiral disk Galaxy
will collide and coalesce with the slightly larger
Andromeda spiral disk galaxy in the next few billion
years.
|
January February March April May June July August September October November December |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: galaxy formation - spiral galaxy - Milky Way
Publications with words: galaxy formation - spiral galaxy - Milky Way
See also: