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.
It’s now two weeks from the New Horizons close flyby of Pluto and Charon. The images are flowing, science data are streaming in, and the team has made pictures almost immediately available online for the rest of us to marvel at. I know for a fact that this mission has taken science educators as well as scientists by storm, and the mission itself has made a lot of information available to educators, the media, and the public. In a delightful development, it has also caught the imagination of artists and musicians as well.
A great many very talented astro-imaging experts have taken to doing a little processing on those releases, resulting in some fine views and a lot of speculation on social media about we’re almost seeing on Pluto and Charon.
A processed version of a New Horizons image of Pluto and Charon, by C. Menoir-Salvan.
For example, this view is a stacked and processed image from a June 18th release from the New Horizons team. The astro-imager is C. Menoir-Salvan, and his work has spurred a LOT Of discussion about what those features could be.
The clearest views are yet to come, so these discussions among planetary science-savvy folks has been very interesting to participate in and follow. Keep in mind that during flyby, we’ll see some images, but due to the lengthy travel time for the signals from New Horizons, the data will be streaming in over the next year or so! We’ll get to see good images of Pluto now, and then the real scientific treasure will make its way to the mission teams. New Horizons is really the scientific gift that keeps on giving!
The Artistic View
Pluto and Charon, a space artist’s view of the pair, with a distant Sun in the background. Copyright David A. Hardy/astroart.org
Artists and musicians are being inspired by the whole Pluto thing as well, with some lovely additions to the STEAM (Science, Technology, Engineering, Arts, and Math) realm. Here are a couple of the many examples I’ve seen float across my view the past few days. The British space artist David Hardy offered his view of what Pluto and Charon look like. He’s very tuned into the science behind what planetary surfaces can look like, and he graciously allowed me to share his view of the double planet here.
Pluto, Charon, and the Sun — a space art scene by scientist and space artist Dan Durda. Copyright Dan Durda.
Dan Durda is a space artist and planetary scientist at Southwest Research Institute in Boulder, Colorado, who has been inspired by New Horizons and the mission to Pluto in more ways than one! Here’s one of his depictions of Pluto and Charon, with the distant Sun shedding a bit of light on the scene. Both Dan and David are members of a wonderful organization called the International Association of Astronomical Artists at IAAA.org, and I count a number of the members as friends and colleagues.
In the music department, there are folks out there creating Pluto tunes and pieces inspired by the distant system. My own favorite composer, Geodesium (the stage name of Mark C. Petersen), created a piece called “Charon” for a project a while back. You can hear a snippet here. It’s on the album Stellar Collections.
Pluto (in the background) and Charon (foreground), as depicted for a press release from Gemini Observatory. Pluto/Charon models from ourtesy of Seeker (Software Bisque); plumes and ice fields added by Mark C. Petersen, Loch Ness Productions. Starfield from DigitalSky 2, courtesy Sky-Skan, Inc.
It’s a space music composition meant to evoke Pluto’s cold, forbidding-looking, yet intriguing companion world and I like to think of it as Charon’s siren song.
Mark also created a vision of Pluto and Charon for a Gemini Observatory press release a few years ago, when astronomers found evidence of possible geyser-like or ice volcano action on Charon. He used a program called Seeker (from Software Bisque), added in a DigitalSky starfield, and some plumes that were indicated in the observations. I can’t wait to see if this vision, as well as Michael’s and Dan’s, have played out for real. Certainly the preliminary science results indicate something interesting happening at these worlds!
New Horizons PI Alan Stern sent me a link to an amazingly cool song written by singer-songwriter Craig Werth and performed by NYC-based folksinger Christine Lavin, who also went out and filmed a lot of people for the segment. It really shows their love of Pluto. The song is called “Oh Pluto!”, and it’s a great tribute to Pluto and its popularity. You’ll see and hear a number of folk legends, an actor from “The Sopranos”, a band member from Dropkick Murphys, as well as men, women, boys and girls from all walks of life, sending their greetings to Pluto.
There are many more folks paying tribute to Pluto in their own ways — they’re engaged, entranced, and excited by the exploration and the discoveries to come. Whoever you are, wherever you are, use your own talents to salute Pluto, and also to the people on the New Horizons mission. They’re dedicated scientists, students, technicians, administrators — all working really hard to bring this distant world into focus for the rest of us! (P.S. If you know of other space artists and musicians who have created works about Pluto, let me know in the comments and I’ll do a second entry, soon!)
