The photo above is is a true-color photograph of the nucleus of Comet 67P/Churyumov-Gerasimenko.
The other photos were black and white, and I tried to make them match.
When Comet C/2023 A3 Tsuchinshan/ATLAS came through in November last year, many of us delighted in seeing a comet with a beautiful tail without optical aid. It far surpassed my expectations in the light of a nearly full moon. It is widely known as a “Comet of a century.”
Some other spectacular comets have also been given this title when they occurred. I’m looking at an article on the Astronomy.com website titled “15 Greatest Comets of our Time.” As I skim down through this article, it is fun to me to chug back down Memory Lane and “revisit” some of these that I/we enjoyed when they passed by. Prior to the recent comet, by far my most memorable was Comet Hyakutake, but there were others too.
About a year after Comet Hyakutake dazzled us, Comet Hale-Bopp-Shenk came through. Well, sort of. Its real name was Comet Hale-Bopp. I added Shenk for fun because the late husband of our Mailbox editor Elizabeth Ann Shenk, saw this comet in the early morning sky before he learned a comet was coming through. As I recall, he called a radio station to find out what he was seeing. They checked and then told him it was Comet Hale-Bopp. Raymond told me he thought it should be Hale-Bopp-Shenk because he discovered it too.
Comet Lovejoy, Comet PanSTARRS, and Comet NEOWISE also made the list of fifteen greatest, and are comets our family has delighted in seeing and photographing.
A week ago when I first saw a close-up photo of the surface of a comet’s nucleus, my appreciation of comets rose to a whole new level. I’d been told a comet nucleus compares to a dirty snowball. So, in my mind, they are featureless, dirty snowballs a couple of miles in diameter blitzing through. To see this “dumbbell-shaped” comet made me do a double-take.
In my reading, I learned these photos came from a spacecraft that orbited the comet between 2014 and 2016. Interestingly, the comet reached perihelion on August 13, 2015, in the middle of the Rosetta spacecraft’s time orbiting it.
Rosetta’s lander, Philae, landed on the comet’s surface November 12, 2014. This was the first time a spacecraft landed on a comet nucleus. Ultimately the mission ended with the Rosetta spacecraft landing on the comet in its Ma’at region.
Click to enlarge diagram.
In searching for a photo of the Rosetta spacecraft I found this chart. Rosetta, its lander Philae, and Comet 67/P are not shown to scale.
Thrusters intended to hold Philae to the surface of the comet by providing a downward thrust could not be activated. This resulted in the lander bouncing several times. After the first bounce, the lander bumped into a cliff. The lander stopped at the fourth touchdown. By making contact with the comet’s surface four times, the feet of the lander “felt” the difference in surface texture, from soft several centimeters deep to much harder.
Click to enlarge diagram.
