APOD: 2026 July 12 Б Galaxy NGC 474: Shells and Star Streams
Explanation:
What's happening to galaxy
NGC 474?
The multiple layers of emission appear strangely complex given the relatively featureless appearance of the
elliptical galaxy in less deep images.
The cause of the
shells is a topic of research, but they
are possibly
tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years.
Alternatively, the shells may be like ripples in a pond, where the ongoing collision with the spiral galaxy just to the right of
NGC 474 is causing
density waves
to ripple through the galactic giant.
Regardless of the actual cause, the featured image dramatically highlights the increasing evidence that the halos of some elliptical
galaxies are surprisingly complicated.
Similarly, the halo of our own
Milky Way Galaxy
is one example of such
unexpected intricacies.
NGC 474 spans about 250,000
light years and lies about
100 million light years distant toward the constellation of the Fish
(Pisces).
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.
