If you remember back in 2016, the European Space Agency navigated its probe, Rosetta, to Comet 67P. No big deal, right?
Well. The probe had a lander, named Philae. That’s right – a lander for a COMET.
Comets are similar, but very different from asteroids. They’re similar in that either one impacting the Earth would probably ruin your day.
But, while asteroids are large chunks of rock and metal, comets are giant clumps of ice and dust. Comets are only visible to the naked eye if they’re rather large, and only once they’re close enough to the sun to have solar radiation and solar wind affect them. While there are over 5000 known comets, unfortunately only one comet a year is visible to the naked eye, and even then it’s not very spectacular. On average, a “great comet” makes an appearance once every decade, though.
The only comet I recall seeing myself was Hale-Bopp about 22 years ago, well before I was old enough to truly appreciate it for what it was. The last comet that put on a real show made an appearance in 2007, but only in the southern hemisphere.
But the European Space Agency (ESA) targeted Comet 67P with the goal of being the first space agency to “soft land” on a comet, meaning the lander would survive the impact.
They managed to soft land Philae on the comet, which itself is incredibly impressive. After all, the distance involved means that signals to/from Earth would take too long to get to the lander, so the lander had to get itself safely onto the surface of the comet. Unfortunately, the lander’s anchoring harpoons failed to deploy, and a thruster intended to hold Philae on the surface didn’t fire, meaning ESA lost contact with the lander sooner than they originally anticipated.
Luckily though, twitter user @landru79 was able to piece together images to make this incredible GIF:
While it looks like it’s “snowing” on the comet, LiveScience explains what’s really happening:
Up close to the camera, dust particles backlit by the sun are likely moving around, mimicking the look of snow on Earth. Cosmic rays may also be creating snow-like artifacts on the images. And those dots in the background, that appear to be falling straight down and disappearing behind the cliff? Those appear to be stars, which look like they’re falling because the comet is rotating as it orbits the sun every 6.5 years.
The clip has also been sped up a great deal, enhancing the drama.
According to the creator, the first frame of the GIF is an image shot June 1, 2016, at 3.981 seconds past 5 p.m. UTC (1 p.m. Eastern). The last frame is an image shot at 17.017 seconds past 5:25 p.m. (1:25 p.m. Eastern) on the same day. That means that a bit more than 25 minutes worth of action is compressed into this short clip, so everything appears to be moving much faster than it did in reality.
But none of that is to detract from what landru79 pulled off here, which captures something close to the drama of standing on the surface of a far-away comet (though we’ve never tried that).