Tonight's Sky
Sun
Sun
Moon
Moon
Mercury
Mercury
Venus
Venus
Mars
Mars
Jupiter
Jupiter
Saturn
Saturn

Tonight's Sky — Change location

OR

Searching...

Tonight's Sky — Select location

Tonight's Sky — Enter coordinates

° '
° '

Great Ursa Major galaxies

Harrington
As darkness falls, the nighttime curtain over the spring sky reveals myriad galaxies scattered across the expanse of the universe. Although most are too dim to be seen through binoculars, a few noteworthy exceptions beckon us to hunt them down.

Of those, my favorites are a celestial version of The Odd Couple: M81 and M82 in Ursa Major. Nowhere else in the sky do we find such an unusual pair. On one hand, we have a textbook example of a spiral galaxy. Like Felix Unger, it appears neatly arranged and well groomed. On the other, we have Oscar Madison, an unkempt, disheveled galactic mess.

Like Felix and Oscar, they live right next to each other in space, and have an undue influence on each other’s existence — some good, some bad.

The Felix Unger of the pair is M81, a model Sb spiral system. The galactic arms in Sb spirals are wound moderately tightly around their galactic core. Color photographs show a bluish-white tint to those arms due to the many young, scorching stars found within. The core appears yellowish, a telltale sign of more mature stars.

Astronomy magazine subscribers can read the full article for free. Just make sure you're registered with the website.

Already a subscriber? Register now!

Registration is FREE and takes only a few seconds to complete. If you are already registered on Astronomy.com, please log in below.
ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter.

ADVERTISEMENT
ADVERTISEMENT
ExploringMarsBooklet_2

Click here to receive a FREE e-Guide exclusively from Astronomy magazine.

Find us on Facebook