Astronomy Picture of the Day

NASA ^ | 6/13/10 | Tunç Tezel (TWAN)

[sig226]

Retrograde Mars
Credit & Copyright: Tunç Tezel (TWAN)

Explanation: Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun. During the most recent such pass late last year and early this year, Mars as usual, loomed large and bright. Also during this time, Mars appeared to move backwards in the sky, a phenomenon called retrograde motion. Pictured above is a series of images digitally stacked so that all of the stars images coincide. Here, Mars appears to trace out a loop in the sky. At the center of the loop, Earth passed Mars and the retrograde motion was the highest. Retrograde motion can also be seen for other Solar System planets.

[sig226]

[Jim W N]

Retrograde motion can also be seen for other Solar System planets.

It's Bush's fault.

[raybbr]

Okay, now I get it....

[left that other site]

ha ha ha! I wouln’t be surprised if the moonbats would agree with you, that a retrograde Mars probably was responsible for President Bush and the War in Iraq. Or Vice Versa.

Or BOTH!

LOL

[Young Werther]

The sky is full of Retro Grade A heavenly bodies.

BTW, You're mooned!

[scoobysnak71]

Correct me if I’m wrong (I didnt look it up first), but I think this is also called Jupiter’s Dance, right? (I seem to remember that Jupiter does the same thing and confounded astronomers for many years as to why.)

[FrankR]

Aren’t there any astonomy blogs on the internet?

[sig226]

Yes. See post 4.

[sig226]

Too many to list.

[sig226]

That is certainly the Astronomy Picture of the Day.

[Young Werther]

It’s Phobus and Deimos the twin moons of Mars!

[fieldmarshaldj]

Not guilty and not guilty. (But do you have more frontal shots to determine butterface guilt or innocence ?)

[Young Werther]

Sorry, If I reveal then you must die!

[Paladin2]

It appears to be a system with twined, barely hidden Uranus.