Throughout human history, comets have been distant, mysterious heavenly bodies. The hunks of rock and ice streak through the sky, streaming bright tails of gas as the sun warms them.
On Wednesday, mankind finally made contact with one. The Rosetta spacecraft defied all odds and dropped its payload, a comet-sniffing probe named Philae, on a cold, speeding target more than 300 million miles from Earth.
Although scientists aren’t yet sure that the probe will be able to anchor itself securely, for now its systems are operational and responsive.
Swaddled inside the comet are the secrets of the early solar system, the elements present when the sun was new and the planets were forming. To study a comet up close would be a cosmological dream, a time capsule like scientists have never laid eyes on. The black ice of these comets keep those secrets largely hidden.
This one is named 67P/Churyumov-Gerasimenko, an ancient comet that fell from a cluster of similar bodies near Neptune years ago. Now in an elliptical orbit around the sun, it has been getting closer and closer to Earth with each go around. But to really get an intimate look at the comet, scientists knew they’d have to get right on top of it.
“The orbiter itself will do a great job of figuring out how the comet works as a machine, and how it responds to the sun,” said Claudia Alexander, a project scientist. “This is a very alien body, this comet. It’s this weird extraterrestrial ice. We want to understand the physics of how a body like this works.”
It also is believed to hold clues to the formation of the solar system. The core of a comet contains molecular building blocks that have not changed in billions of years and provide a glimpse into the origin of the planets.
But even if everything goes well with Philae, it will only collect data until March, when the comet will be too close to the sun.
When mission control saw the data that confirmed a landing - and a soft one, at that - their nervous looks melted into smiles, and then hugs and cheers. Philae was safe and sound, and sending data back to Earth.
“The data collected by Rosetta will provide the scientific community, and the world, with a treasure-trove of data,” NASA astronaut and administrator John Grunsfeld said in a statement. “Small bodies in our solar system like comets and asteroids help us understand how the solar system formed and provide opportunities to advance exploration.”
But it wasn’t all good news. A few minutes later, Rosetta scientists announced that Philae hadn’t deployed the harpoons that would anchor it to the comet’s surface. Without this stability, the probe could move into any position, and it has very little chance of righting itself again. The team told press they would consider firing the harpoons again, and would update when they knew more.
