|From the European Space Agency Rosetta project|
Rosetta will orbit 67P and take all sorts of pictures and measurements, and then, remarkably, will send down a landing craft to probe even deeper. It will find out how much ice is on the comet and what other material it may contain, presumably including carbon. That's been a primary part of the news releases. But why carbon, and what's so important about carbon as opposed to some other sorts of compounds? Herein lies the hype and at least an apparent major rationale for doing this since, after all, we know from various sources what comets are basically made of. As put today by the BBC's report, "The mission aims to add to knowledge of comets and their role in ferrying the building blocks of life around the early Solar System."
This sounds interesting and like a nice justification for a many-billion Euro adventure. Astrophysicists will learn at least some new things about the structure and composition of this particular rock. But will 67P tell us much about anything other than itself, that we don't know already directly and indirectly about the trillions of other comets in the cosmos? I say this because the idea that we'll be discovering the origin of Earth-life's materials seems a rationale as flimsy as, say, a clump of damp dust.
I know very little cosmology, but one thing I think I do know, if current science is at all correct, is that the "building blocks of life" did indeed come from comets and other space-dusty rocks and detritus. What we have long known is that water, carbon, and all the other complex molecules of life (and, for that matter, of rocks, seas, weather and the Earth entire) came from 'outer space'. Where else could they have come from?
These molecules are formed in processes called nucleosynthesis, that occur inside stars. The cosmos had none of it at the time of the Big Bang. Only when stars form, exist for a while, then explode in death, does this material get scattered into space. Then, due to gravity and possibly other factors such as molecular adherence these molecules, essentially space dust, coalesce into larger and larger clumps, rocks that become captured in orbit around new-forming or existing stars. All that you're made of was in turn made in some former, no-longer-existing star, long before our Sun came into existence.
The Earth, and everything on it that life is made of, got here by collapsing and accretion from space-blown material. The stuff of 67P is just like what we already think we know was the source of similar molecules on earth. Whether they got here during the original accretion, or by space-fall thereafter, it's the same kind of process. We know the Earth is hit from time to time by such space missiles. The bottom line is that everything that's here got here from space. The only somewhat relevant, but in that sense not so very important question is how much carbon and water came after the Earth existed as a big rock, and how much was part of Earth's formation.
We know with reasonable certainty that life didn't arise until there was enough water and carbon etc. here for biomolecules to form. We know roughly when that was (3-4 billion years ago, in a 4.5 billion-year old Earth). If these vital molecules were here at Earth's beginning, than life arose only when things had cooled down enough, and perhaps water had eroded enough minerals and carbon and so on from solid rock, etc. If the cosmic rain was responsible for some or even most of the water here (which seems very unlikely, given how prominent water is all over the universe), that tells us little that's different.
Pro-science or a science spoil-sport?
So is such a mission worth its cost when there are things to do with public funds other than to develop sky toys for scientists to play with? We are in favor of science--good science, properly represented. But science should tell less puffed-up stories, and the public should be better-informed.
In this case, better-informed would be to be told that (unless cosmological theory is missing something important today, which is not what the press releases suggest) all Rosetta is doing is poking around in one sample of the stuff we were made by, that all came from space, as did the Earth itself. If even knowing that, we still want to spend the funds on what are really little more than costly real-life video games, great!
For those of us without a major disease and who have shelter, security, and enough to eat, this is interesting stuff to watch, not more costly than cable TV subscriptions (maybe less, depending on your channel line-up). But to hype this as is being done, gives the impression that Earth got here by some other means than gravitational accretion of former star detritus. That's misleading, bad science. Why is such need felt by the scientists (or the institution's PR office) to give it such spin? Is it that they realize that without the spin they'd have no funding? If so, then the public is being bilked. If not, then let's have real science from these experts.
Here's something much more interesting
To be fair, some of what we get from our space cadets really is interesting for more than a "Wow, how did you manage that?" factor. Yesterday also, NASA (perhaps not wanting to be upstaged by the Europeans?) released this image of a near-perfect hexagonal pattern, referred to as a 'storm', on Saturn's north pole region:
|Photographed from the top of Saturn. From NASA|
As a former meteorologist myself, I find this very interesting. Spacecraft first found this many years ago, but we only get an occasional direct look. The curious aspect of the pattern, is that it's a hexagon rather than more sinuous wave such as we get here in Earth's weather (and seas, for that matter). How can fluid dynamics generate such a rigid-appearing, angular form on a basically spherical surface? Is something on Saturn alien to our own planet? Different physics?
In fact, the report says that physicists have now generated similar patterns in the lab, identifying the conditions that are responsible and showing that nothing strangely unearthly is going on in our sister planet. Still, seeing these far-off things close-up for the first time has lead to learning, and is captivating--even if, as in 67P, it doesn't show us anything alien to our experience here at home.
These images from far away evoke an emotional awe: there truly is, way out there and so far beyond, more of what we see right here. It exists, all alone and cold and dark, perhaps known to other creatures, yet the same as what we have here. Little ice crystals, rock dust, shapes we recognize that we might find in our own back yard.
These thoughts reinforce the amazing, remarkable fact that there really do seem to be laws of Nature, that what we can see nearby applies way out there where we can hardly catch glimpses--a point Isaac Newton stressed. Very much to think about. Good science really does tell us about the nature of the world, in ways no other means has yet been able to do. We puny humans, blobs of stuff that evolved from space-stuff, have figured this out! That's a thought of cosmic proportions.