Against all odds, Philae has confirmed that the first ever drilling of a comet has happened! ESA has received telemetry data indicating that the drill went down and up. The probe will now analyse whatever material the drill has managed to grab. What is Philae going to find? Perhaps the building blocks of life?
This is to me the most exciting part of this mission: COSAC—the Cometary Sampling and Composition experiment—is now going to analyse the soil grabbed by the drill in search of complex organic molecules. If they find them, it will be further proof than planetary life—or at least the building blocks for it—could travel across the universe in a process known as panspermia.
What is panspermia?
Basically, panspermia is the theory that says that life or its building blocks could have originated in other places across galaxies and planetary systems, travelling through space in comets and asteroids that resulted from collisions. It sounds like a crazy concept, but NASA planetary scientist Chris McKay explained in this io9 article why this is a perfectly valid theory that requires further investigation:
1. The geological evidence for the earliest life on Earth is very early, soon after the end of the late bombardment. There is good evidence for life on Earth at 3.5 billion years ago, indirect evidence at 3.8 billion. The end of the late heavy bombardment is 3.8 billion years ago.
2. The genetic evidence indicates that the last universal common ancestor (LUCA) of life could have been roughly 3.5 billion years ago (but with large uncertainties) and that LUCA was a fairly sophisticated life form in terms of metabolic and genetic capabilities.
1 and 2 together give the impression that life appeared on Earth soon after the formation of suitable environments and it appears to have come in being remarkably developed - like Athena born fully formed from the head of Zeus.
3. Rocks from Mars have traveled to Earth and the internal temperatures experienced in these rocks during this trip would not have sterilised the interiors. Thus in principle life can be carried from Mars to Earth.
4. Mars did not suffer the large Moon-forming impact that would have been detrimental to the early development of life on Earth.
3 and 4 have lead to the suggestion that Mars would have been a better place for life to start in the early Solar System and it could have then been carried to Earth via meteorites.
5. Organic molecules are widespread in comets, asteroids, and the interstellar medium.
6. Comets could have supported subsurface liquid water environments soon after their formation due to internal heating by decay of radioactive aluminium.
7. As comets move past the Earth they shed dust which settles into Earth's atmosphere.
5, 6 and 7 have lead to the suggestion that life could have started in the interstellar medium or in small bodies such as comets and then been carried to the Earth by comet dust.
So, yes panspermia is a valid scientific hypotheses and warrants further investigation.
Personally, it's a favourite theory of mine. The entire idea of life travelling across galaxies to seed other planets is fascinating.
In other good news, ESA has confirmed that the rotation manoeuvre has been successful: Philae has turned 35 degrees! "Looks like a whole new comet from this angle!" they say. Looking forward for the new pictures, but especially from the data from COSAC.