The Coma Glaxaxy Cluster

that is a whole lot of galaxies
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Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! The above mosaic of images of a small portion of Coma was taken in unprecedented detail in 2006 by the Hubble Space Telescope to investigate how galaxies in rich clusters form and evolve. Most galaxies in Coma and other clusters are ellipticals, although some imaged here are clearly spirals. The spiral galaxy on the upper left of the above image can also be found as one of the bluer galaxies on the upper left of this wider field image. In the background thousands of unrelated galaxies are visible far across the universe.

Photo of the Day: This is What a Sunset Looks Like on Mars

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In case you were curious, here is what an alien sees before he/she/it goes to sleep.

NASA’s Curiosity Mars rover captured the above image on April 15, and it’s being described as the first sunset observed in color by the spacecraft.

The photos were taken last month, but they were just sent back to Earth last week.

While Mars may appear red, the sunset is actually blue, and the Jet Propulsion Laboratory explains why this is possible:

Dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors. That causes the blue colors in the mixed light coming from the sun to stay closer to sun’s part of the sky, compared to the wider scattering of yellow and red colors. The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at mid-day.

Curiosity first landed on Mars’s Gale Crater in August 2012 with a mission of determining whether or not Mars is or ever was habitable by life forms.

Here’s an animated GIF of the sunset, which uses a series of photos takes over a period of about 6 minutes, 51 seconds. The sight apprently inspired the rover to recite some lines from T.S. Eliot’s “The Love Song of J. Alfred Prufrock” on its Twitter account.