Mars

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.

Via MNN:

Ancient Mars featured flowing rivers and sizable lakes — but that doesn't mean the Red Planet definitely could have supported life, one prominent researcher stresses.

The presence of liquid water is just one of many factors that researchers need to take into account when investigating the past or present habitability of Mars or any other cosmic body, astrobiologist and mineralogist Pamela Conrad wrote in a "Perspectives" piece published online on Dec. 11 in the journal Science.

"The things that make a place livable are numerous, and sometimes, there's a showstopper you didn't think of," Conrad, deputy principal investigator for the Sample Analysis at Mars instrument aboard NASA's Curiosity rover, told SPACE.com. "So it's important to take a poll of the diversity of attributes that could contribute to making an environment livable or not."

Via NY Times:

Today Mars is an arid, frigid desert, suggesting that the mother of all climate changes happened there, about four billion years ago or so. The question that haunts planetary scientists is why? And could it happen here?

"I think the short story is the atmosphere went away and the oceans froze but are still there, locked up in subsurface ice," said Chris McKay, an astrobiologist and Mars expert at NASA's Ames Research Center.

In September a new spacecraft known as Maven, the Mars Atmosphere and Volatile Evolution mission, swung into orbit around the planet. Its job is to get a longer answer to one part of the mysterious Martian climate change, namely where the planet's atmosphere went.