Astronomy Picture of the Day -- Earth at Night

Dec 8, 2012 Full story: Free Republic

Explanation: This remarkably complete view of Earth at night is a composite of cloud-free, nighttime images.

Full Story

“Geologist [I'm Climate Change]”

Since: Mar 07

formerly Nuneaton

#1 Dec 10, 2012
This one showed up on CNN and drew some favourable comments.

There looks to be an upside to the telescope view blocking light pollution that gets in the way of amateur astronomers.

Have a nice day: Ag
litesong

Lynnwood, WA

#2 Dec 10, 2012
The lights of Las Vegas attract human gamblers to Nevada. Whether we shuffle cards or not, all humans now gamble for much bigger stacks..... that aliens from other parts of the Universe, attracted by our lights, will be......... friendly.
Adrian..... have you noted the two little lights in the bottom left hand corner of your avatar, showing galaxy M104? They aren't two stars. They are two spiral galaxies, I'm assuming have what?...... 100+ billion stars each!
I wonder if they may be gravitationally orbiting one another, or separated by millions of light-years.

“Geologist [I'm Climate Change]”

Since: Mar 07

formerly Nuneaton

#3 Dec 17, 2012
litesong wrote:
The lights of Las Vegas attract human gamblers to Nevada. Whether we shuffle cards or not, all humans now gamble for much bigger stacks..... that aliens from other parts of the Universe, attracted by our lights, will be......... friendly.
Adrian..... have you noted the two little lights in the bottom left hand corner of your avatar, showing galaxy M104? They aren't two stars. They are two spiral galaxies, I'm assuming have what?...... 100+ billion stars each!
I wonder if they may be gravitationally orbiting one another, or separated by millions of light-years.
Difficult.

The info for redshift for the 2 small background galaxies is not available in the ngc info (they are too faint).

The galaxies may be aligned by line of sight as in the NGC55 versus sculptor group (NGC55 is 3 million light years closer than ngc253 which is the core galaxy of the sculptor group, where both galaxies appear similar sizes due to distance).
Then again the galaxies may constitute a gravitationally bound pair in a small group.

The answer is difficult to give unless you happen to be there.

Ah almost forgot. about 1/4 of galaxy interaction pictures are line of sight overlaps where a similar sized foreground galaxy is superimposed over a background system. They can however on occasions be very odd superimpositions. One example being the giant elliptical galaxy M60 and a blue spiral in the background, still part of the virgo cluster, seen through the outer layers of the giant E, and entirely within the globular cluster halo of the foreground M60.

Have a nice day: Ag

Tell me when this thread is updated:

Subscribe Now Add to my Tracker

Add your comments below

Characters left: 4000

Please note by submitting this form you acknowledge that you have read the Terms of Service and the comment you are posting is in compliance with such terms. Be polite. Inappropriate posts may be removed by the moderator. Send us your feedback.

Space Discussions

Title Updated Last By Comments
Top 5 Employers in Colorado: Which Companies Ha... Feb 28 Elise Gingerich 1
School boards celebrate education (May '13) Feb 21 hard 4 parents to... 3
God and Soul in Quantum Theory. / By Socratus. / Feb 18 socratus 1
Mars with the plume identified within the yello... Feb 18 SpaceBlues 1
NASA ship provides mesmerizing images of sun Feb 17 Kid_Tomorrow 1
Dialing ET, but maybe getting Klingons: Scienti... Feb 16 Softscience 4
1st Chinese female astronaut gives birth Feb 13 Kid_Tomorrow 1
More from around the web