Daily Archives: July 1, 2015

New Horizons mission, Pluto

The Two Very Different Sides of Pluto

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Color Images Show Amazing Features

Color images released on July 1, 2015, show very different faces of this distant world. The image on the left is the hemisphere New Horizons will encounter first, and the one on the right is the opposing side. Courtesy NASA/New Horizons/JHU-APL

Just when you thought Pluto couldn’t surprise you more, here come images of its two hemispheres, showing very different landscape markings. The image on the left is what New Horizons will see first during the encounter, and it seems to have a good mix of dark and light features on the surface.

That image on the right, though — whoa! What looks  like four evenly-spaced “somethings” along the limb (which is the equator). And a sort of dark crescent up above that? Craters? Hills? Canyons? What could they be? The answer to that will be tantalizing the New Horizons team until the next images show up. It’s safe to say, nobody’s seen anything quite like these views before and Pluto is definitely giving us something to think about.

Also, notice how much more colorful Pluto is compared to its companion world, Charon, which is darker and grayer. What’s up with that?  In another 13 days or so, we’ll know even more than we know today. But, for now, the glimpses are just getting more tantalizing even as the view clears up. Clearly, Pluto is not a frozen dead world. Its atmosphere is still there (that is,  it hasn’t frozen out yet, which will happen as the dwarf planet gets farther away from the Sun), and the different terrains and bright-and-dark markings are telling us that Pluto still has many surprises to deliver.

Comet 67P/Churyumov-Gerasimenko, rosetta, rosetta spacecraft

It’s the Pits On Comet 67P

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From Sinkholes to Jets

Active areas with sinkholes and pits on the Seth Region of Comet 67P/Churyumov-Gerasimenko. The central pit is about 220 meters across and 185 meters deep. Courtesy ESA/Rosetta/MPS for OSIRIS team/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

It’s quite a week for solar system exploration news. Pluto (which is way more than a planet!) continues to be on everybody’s mind with the upcoming close flyby of the New Horizons mission.  Dwarf planet Ceres is still getting the once-over from Dawn. And, today we’re starting to get more high-resolution images from the Rosetta mission’s OSIRIS camera as it scans Comet 67P/Churyumov-Gerasimenko.  Check out this latest image, showing sinkholes and pits on the surface. It’s more than likely they play an important role in creating the jets of dust we see flowing away from the nucleus. A number of the dust jets trace back to these pits, and that’s giving mission scientists a peek into the interior processes that drive those outbursts.

Active Pits and Sinkholes

Scientists have found at least 18 pits, sort of circular in shape, across various parts of the cometary nucleus. They range in size from a few tens of meters across to a few hundred meters. The deepest ones are around 210 meters, and their floors seem to be covered in dust. Other images of the comet show dust jets rising up from fractures in the walls of the pits. The fractures mean that there are volatiles (gases and ices) just below the surface. AS those materials get warmed by the Sun, they expand, and that forces cracks into the sinkhole walls. The trapped materials, plus dust, come rushing out of the cracks and out to space, creating the jets we’ve all been seeing emanating from the comet.

The pits likely form as the materials rush out, leaving behind a cavity under the surface. The cavities could also have existed since the comet was formed, or some other heating caused ices to vent out after the upper layers warmed up. However the cavities formed, eventually their ceilings can’t hold up any more, and they collapse, creating the pit.

Comet 67P is due to make its closest approach to the Sun on August 13, 2015. The Rosetta spacecraft is orbiting the comet’s nucleus and will be charting how the comet changes up to, during, and after perihelion. The newly awakened Philae lander may also contribute observations, depending on how well it can communicate with the orbiter. This mission is giving us all a new look at some very old ice as it makes its passage through our part of the solar system.

Want to follow the mission? Check out the Rosetta mission pages for more images and announcements.