Much of our attention on Pluto has been centered on Sputnik Planum, the vast plain home to floating nitrogen ice glaciers. But, there’s another feature drawing the eyes of the New Horizons team – Cthulu Regio. It sits just to the west of Sputnik Planum and looks kind of like a whale.

whale shaped Cthulu region

The New Horizons team believes several of Cthulu’s mountain peaks are covered in methane ‘snow.’

Cthulu stretches for 1,850 miles and is 450 miles wide. Imagine a feature slightly larger than the state of Alaska. Its geography runs the gambit of Pluto’s features. From mountain chains to smooth terrain. Heavily cratered and fractured areas also dot the 1,850 mile-long region. So, what is Cthulu’s defining feature? A dark surface scientists believe is caused by a layer of dark tholins. Tholins are complex molecules created when sunlight interacts with methane. The enhanced color image below highlights this region.

Pluto snow covered mountains

You see the snow covered peaks in the zoomed-in box? Scientists think methane is condensing as ice on top of these peaks. “That this material coats only the upper slopes of the peaks suggests methane ice may act like water in Earth’s atmosphere, condensing as frost at high altitude,” said John Stansberry, a New Horizons science team member.

The right inset image shows data from the Ralph/Multispectral Visible Imaging Camera (MVIC). The purple colors represent methane and line up almost perfectly with the enhanced color view of the ‘snow’ covered peaks.

Clouds on Pluto?

New Scientist has the scoop on this story. The website claims to have seen emails sent to scientists discussing the formation of clouds in Pluto’s atmosphere. Check out this image.

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possible clouds on Pluto

New Scientist writes:

“Grundy has spotted features in the haze on the edge – or “limb” – of Pluto that seemed to stand out from the distinct layers. But more intriguingly, he had also seen a bright feature crossing different parts of the landscape, suggesting it was hovering above.”

Let’s break this down. The features circled do look like clouds. Plus, the features on the “limb” appear much more distinct than the general haze of Pluto’s atmosphere. What are they made of? According to New Scientist, researchers didn’t speculate. But, it’s safe to assume they are made up of the compounds already discovered in Pluto’s atmosphere – nitrogen, methane, acetylene and ethylene.

Why hasn’t New Horizons come out and announced it? Obviously, they’re not 100% sure they are looking at clouds. One of the biggest issues with the Pluto mission, is scientists only have about half the data from the flyby. Because of the vast distances at play here, New Horizons will be sending data back to Earth for another six months (at least). The New Horizons team expects “Pluto encounter data playback” to wrap up sometime between October and December.


We’ll continue to learn much more about Pluto in the coming months. One date to keep an eye on is November 2017. A science conference covering the encounter with the Pluto system is tentatively dated for then.

Ever wonder about the work behind the scenes for downlinking all of this data? Emma Birath, from the Southwest Research Institute in Boulder, Colorado, leads a team that makes the release of all of these interesting images easier. From a recent NASA blog post:

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“To facilitate the playback of New Horizons’ encounter data, I led an effort to build a piece of software, called DataTrack. DataTrack consists of a web-based user interface, with a MySQL database backend. It allows us to schedule and sequence playbacks for each command load sent to the spacecraft. It helps us keep track of all data sets from the encounter load, and at what stage they are in the downlink process. It also helps us track the processes of mathematical data compression on New Horizons, which is necessary to maximize how much data we can get back to the ground each week and month. Has a data set been compressed already? What compression type was used? What is the estimated data volume, and will it fit in an upcoming downlink track? It flags errors that may be introduced in a playback sequence, and ensures efficiency and optimization.

Flying a spacecraft is risky, and at any time something could happen in which we lose contact and any information that hasn’t already made it to the ground, so the prioritization of the data sets by the science team is critical. DataTrack allows us to keep track of what’s been sent to the ground, what’s scheduled to be sent, and what’s left to plan for; it also lets us track what data has been compressed.

Another important purpose of the software is to provide the science team with information on when a particular data set is expected to reach the ground. It has greatly improved communication across team boundaries.”

Image credits: NASA

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