Last week, something amazing happened: after hibernating for 31 months while cruising through space hundreds of millions of miles from Earth, the European Space Agency probe Rosetta woke up from its slumber and sent a message home: "Hello, world!" Rosetta is up and running now that it's nearer the sun and its target, the comet 67P/Churyamov-Gerasimenko.
If all goes well, on November 11 Rosetta will dispatch its smaller cargo, the 200-pound probe Philae, to land on the comet. It will be the first landing of a human-made device on a comet.
The landing will be amazingly hard. With a diameter of less than 3-miles, the comet offers negligible gravity. Philae will have to use a combination of harpoons and ice hooks to grab on to the comet. It will be more like lassoing a bull than making a landing.
Comets are essentially balls of ice and dust left over from the formation of the solar system. They cluster in huge belts along the periphery of the solar system, with sizes varying from a few yards to about 6 miles, or so, in diameter. They are memory repositories of the early infancy of our solar neighborhood: to study them is to study our origins, to go back some 4.6 billion years into the past.
Philae, armed with several scientific instruments, will send images of the comet's surface and environs as it approaches the sun. It will also study the comet's chemical composition, using a 10-inch drill to collect subsurface samples. All this happens at a remove: space probes are sophisticated robots, triumphs of science and engineering, put together to advance human knowledge.
There are two big mysteries related to comets: the origin of our planet's water and the origin of life here. Older models considered that comets were largely responsible for our planet's watery nature. This doesn't seem to be the case any longer, although there is much to learn about the relationship between comets and water. If fact, we don't have an accepted explanation as to why we have so much water here.
We also know that comets have organic matter, that is, stuff related to living organisms, such as a variety of amino acids. Philae will search for amino acids in 67P/Churyamov-Gerasimenko and check to see if they have similar (identical?) properties to terrestrial amino acids. Many scientists think the amino acids that jumpstarted the emergence of life on Earth came from comets and asteroids. To go in situ to study them is a major plus, as it avoids possible contamination of what is found here on Earth. I am hoping that Philae finds amino acids, but with different spatial properties to the ones found here, something I've predicted in a few of my papers.
We shall see!
I am rooting for the complete success of this remarkable mission. But whatever happens, the fact that our probes can reach such a far away object and, hopefully, even land to study its composition is cause for plenty of celebration. It's good to know that we can do better than the dinosaurs if we ever have to face a killer comet or asteroid.