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Spiral Arms

Regions of stars and interstellar matter that extend from the center of spiral galaxies, forming a spiral pattern; in the Milky Way, these include the Orion Arm where our Solar System resides.

Source

APODs including "Spiral Arms"

Spiral Galaxy NGC 2841

29 March 2008

Spiral Galaxy NGC 2841
Image Credit: Panther Observatory / NASA APOD

Some 50 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major. This sharp view of the gorgeous island universe shows off a striking yellow nucleus and galactic disk with tightly wound spiral arms. NGC 2841 has a diameter of over 150,000 light-years, even larger than our own Milky Way Galaxy. The galaxy's dust lanes and turbulent star-forming regions are found along the spiral arms, but X-ray images suggest that resulting winds and stellar explosions create plumes of hot gas extending into a halo around NGC 2841. Of course, the prominent stars with a spiky appearance in the picture are close foreground objects within the Milky Way and not associated with NGC 2841.