Rosetta’s Sweaty Comet Gets Closer

Bi-lobed Comet Nucleus Tumbles Along in Its Orbit

The coma of comet 67P/Churyumov-Gerasimenko as seen with OSIRIS covers an area of 150 kilometers across. This image was taken on July 25th, 2014 with an exposure time of 330 seconds. The hazy circular structure on the right and the center of the coma are artifacts due to overexposure of the nucleus. Courtesy ESA/Rosetta/MPS-OSIRIS Team MPS/UPD/LAM/IAA/INTA/ UPM/DASP/IDA

When the Rosetta mission planners selected Comet 67P/Churyumov–Gerasimenko (67P) as a rendezvous target, they probably didn’t expect the tumbling, rubber ducky-shaped blob of ice and dust they’re now seeing as the spacecraft gets closer to its August 6th arrival at the comet. The past few weeks have been a parade of discoveries at the comet, and today astronomers announced that they’ve seen the coma really start to thicken up around the nucleus. New images from July 25th show a distinctly blobby coma.

Comet 67P has been slowly getting more “active” as it experiences more heat from the Sun, and in April astronomers began seeing evidence of dust production. This happens as the ices (volatiles) start to sublimate (sort of like watching dry ice in sunlight) and they carry along dust and rocky bits as they move away from the comet.  Eventually, that coma should thicken and stretch out to form a dust tail (and presumably a plasma tail, too).  When that happens, Rosetta, and a small lander called Philae, will be there to measure and report on all the action. The lander will also take samples of the comet to study. What it finds will help astronomers understand the comet’s chemical makeup, which also gives them insight into the conditions in the solar system as the comet formed (some 4.5 billion years ago).

The nucleus of comet 67P/Churyumov-Gerasimernko as seen from a distance of 1950 kilometers on July 29th, 2014. Courtesy ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The comet, along with Rosetta and Philae, will make its nearest approach to the Sun in August 2015. That point, called the comet’s perihelion, lies between the orbit of Earth and Mars. The comet was nudged into its current orbit by a close encounter with the planet Jupiter in 1959. Before that, it never came closer than a point somewhere near the Asteroid Belt (around 2.7 astronomical units (2.7 times the distance between Earth and the Sun)).

The Rosetta mission was designed to study all aspects of a comet. This includes using a probe to sample the surface and near subsurface of the nucleus. It’s important to get good images, since the comet’s icy body is tough to “see” as it grows a coma. However, there are other aspects of a comet that also tell scientists quite a bit about its makeup and history. One of the most important is to determine the changes in production rate of water vapor and other gases from a comet as it moves in its orbit, particularly as it begins to “feel” the influence of the Sun.  It turns out that Comet 67P’s nucleus is a sweaty one, losing the equivalent of a couple of glassfuls of water each second!  That rate will likely get higher as the comet nears the Sun, when it could lose many times that much water vapor. Water is a big part of a comet’s nucleus — one of the so-called “volatiles” that outgas as comets experience increased solar heating. The other volatiles are carbon monoxide, methanol, and ammonia. The Rosetta spacecraft has an instrument called the Microwave Instrument for Rosetta Orbiter (MIRO) that measures the volatiles sweating off the comet. The Optical, Spectroscopic and Infrared Remote Imaging System (OSIRIS)  gives astronomers a sophisticated way to take both wide- and narrow-angle views of the comet.  Along with ultraviolet spectrometer, radio-wave instrument, and other subsystems, Rosetta is giving the world a multi-wavelength way to study a comet up-close and personal.

August 6th will be a busy day for the Rosetta team, and I’m sure a LOT of people will be following the progress of the mission. If you want to read more about Rosetta and its cometary target, check out the mission web pages and the Max Planck Institute for Solar System Research’s news updates. Press briefings will be live-streamed, so if you’re interested in real-time information, check ’em out!

Astronomers Without Borders

Bring Astronomy Education to Kids in Tanzania

Last fall I had the great privilege of meeting and traveling with Mike Simmons, the President and Founder of Astronomers without Borders. This organization fosters and follows through on the idea that the stars belong to all of us, and that astronomy is a worldwide cultural and scientific heritage. We happened to be in Poland for a meeting called “Communicating Astronomy with the Public” and as part of our after-meeting trip, we traveled to Torun (the home of Nicolas Copernicus) and visited two “Astrobazas” — observatories built and run by students at their respective schools. It was a great trip and I was really impressed with the level of interest and expertise of the students involved.

One of the projects that AWB is doing is called Telescopes to Tanzania, and it’s the subject of an IndieGoGo fundraising campaign. The group has a goal of raising $38,000 to improve science education Tanzania, and as of this writing, they’ve raised $6,549 with 39 days to go. AWB has been actively working with and supporting Tanzania’s schools since 2011, trying to bring textbooks and other materials to students who don’t have access to even the basic materials that kids in the U.S. and other countries take for granted. The group is using their crowdsourcing campaign to build the The Center for Science Education and Observatory in the country, which will  help students and teachers in the country with astronomy  and science training. By integrating astronomy into the national teaching curriculum, the center will be able to develop and circulate hands-on science and astronomy teaching resources to schools around the Tanzania.  In addition, the center will provide hands-on laboratories, and an astronomical observatory with a portable planetarium, and internet connectivity so that students and teachers can connect one-on-one with science centers and students and educators worldwide.

Do you have some spare cash lying around?  It only takes $5.00 to make just the minimum contribution to the AWB’s effort. Of course, you can (and should, if you’re able) give more. You could even fund the construction of the observatory for $15,000.  Of course, you get cool perks, plus you get the satisfaction of knowing you’re helping one of the world’s premier astronomy outreach organizations bring science awareness and education to the students in Tanzania. Your money will go a long way. Here’s a breakdown of what the $38,000 will cover.

Budget breakdown for the IndieGoGo funds raised by Astronomers Without Borders. Courtesy AWB.

If you can give, please do so. If you’re interested in other projects and accomplishments of AWB, check out their Web page. And, if you want to learn first-hand about AWB and their current project, visit them during their August 6th G+ Hangout. The topic is focused on the development of STEM education in developing world. Anousheh Ansari, astronaut and social entrepreneur Ron Garan, and people from Africa will be joining Mike and the gang. Check it out at the AWB Google+ page and learn more about this remarkable organization.