APOD: 2024 January 1 Б NGC 1232: A Grand Design Spiral Galaxy
Explanation:
Galaxies are fascinating not only for
what is visible, but for what is invisible.
Grand spiral galaxy
NGC 1232,
captured in detail by one of the
Very Large Telescopes,
is a good example.
The visible is dominated by millions of
bright stars and dark
dust,
caught up in a gravitational swirl of
spiral arms revolving about the center.
Open clusters containing
bright blue stars can be seen sprinkled along these spiral arms,
while
dark lanes
of dense interstellar
dust
can be seen sprinkled between them.
Less visible, but detectable, are billions of dim normal
stars and vast tracts of
interstellar gas,
together wielding such high mass that they
dominate the dynamics of the inner
galaxy.
Leading theories indicate that even
greater amounts of matter are invisible,
in a form we don't yet know.
This pervasive
dark matter is postulated, in part, to explain the
motions
of the visible matter in the outer regions of galaxies.
Free APOD Lecture:
January 9, 2024 to the Amateur Astronomers of Association of New York
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
