Curiosity drill site reveals Mars isn’t red - it’s greyish-blue

NASA’s Curiosity rover has drilled down into Mars to collect samples, and it’s revealed that just under the dusty red surface, the Red Planet is actually a greyish blue.

The drilling happened at a site called Telegraph Peak, right up in a region called Pahrump Hills, where Curiosity has been working for the past five months. It’s been drilling into the rocky surface to get some idea of how and when Mars evolved from a wet environment to the dry and dusty one we see today, and in the process has discovered that the dusty red top layer is made up of completely different stuff than the actual planet itself.

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Jupiter’s moon Callisto is not the largest moon in the solar system, or even the largest of Jupiter’s natural satellites. But it does rank highest in one category: it is the most heavily cratered body in our solar system.

Callisto’s surface is about as evenly blemished as you could expect it to be from the random impacts it has received over the eons. Made up of equal parts of rock and ice, it’s surface captures the history of the violent past of the solar system. The outermost of Jupiter’s four Galilean satellites, it is nearly the same size as the planet Mercury, though it has only about one-third the mass of the speedy inner planet.

Callisto orbits Jupiter at a distance of nearly 3 million kilometers (1.8 million miles), considerably farther away from the planet than the other Galilean moons. That relative isolation is one of the reasons for the golf ball-like appearance of the moon. At that distance, Jupiter’s strong gravity exerts less force on Callisto than on the other large moons. Io, Europa and Ganymede pay for their proximity to Jupiter with geological processes like volcanism, plate tectonics and other resurfacing events. Callisto’s surface hasn’t had any such recent rejuvenation treatments, and it carries scars from the early solar system, dating back some four billion years.

This is the only complete full-color view of Callisto obtained by the Galileo spacecraft, which studied Jupiter and its moons from 1995 to 2003.


Image credit: NASA/JPL/DLR


Star on a Hubble diet

The star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 that extends one degree on the sky in the direction of the Scorpius constellation. Part of the nebula is ionised by the youngest (bluest) heavy stars in Pismis 24. The intense ultraviolet radiation from the blazing stars heats the gas surrounding the cluster and creates a bubble in NGC 6357. The presence of these surrounding gas clouds makes probing into the region even harder.

One of the top candidates for the title of “Milky Way stellar heavyweight champion” was, until now, Pismis 24-1, a bright young star that lies in the core of the small open star cluster Pismis 24 (the bright stars in the Hubble image) about 8,000 light-years away from Earth. Pismis 24-1 was thought to have an incredibly large mass of 200 to 300 solar masses. New NASA/ESA Hubble measurements of the star, have, however, resolved Pismis 24-1 into two separate stars, and, in doing so, have “halved” its mass to around 100 solar masses.

Credit: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain). Acknowledgement: Davide De Martin (ESA/Hubble)


Why is our relationship with the moon so one-sided? Let MinuteEarth explain. 

There’s no dark side of the moon, but there is a side we don’t see often. But because of the moons rock-and-rolling libration, that unseen portion is actually less than half the moon’s face:

Follow that with this history of our moon’s violent birth, and then check out this post to tour through a whole catalog of maps of the moon.

Astronomy Picture of the Day: March 1st, 2015

Inside the Coma Cluster of Galaxies


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.

Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA);

Acknowledgment: D. Carter (LJMU) et al. and the Coma HST ACS Treasury Team