Monday, December 27, 2010
There are undoubtedly many goodies on the near horizon for the study of exoplanets. A far better grasp on the number of Earth-sized worlds out there in the galaxy is on its way, thanks to both the Kepler mission and the ongoing efforts of other surveys using radial velocity, transit, and gravitational microlensing measurements. Thus far everything points towards a universe positively filled with small rocky worlds, and undoubtedly many will fulfill several of the basic, albeit biased, requirements for Earth-style climates and surface environments. On the tail of this will be the possibility of rudimentary measurements of atmospheric composition for a few select worlds, most likely orbiting low-mass stars in our neighborhood.
All is good, but these are items that have been written about ad nauseam, in these pages as well as elsewhere. Surely barreling towards our orbital solstice at 30 kilometers a second we can afford a little more reach?
In the next decade or so we should see the advent of the largest optical telescopes ever built by humans. With mirror diameters in the range of 30 meters and advanced adaptive optics, calming and helping eliminate the distortions of the Earth's atmosphere, these goliaths will not only open up exoplanetary studies but also the study of our own solar system. For the first time ever we will be able to make daily (if not by the minute) observations of places like Jupiter's icy Europa with spatial resolution of just a few tens of kilometers, combined with exquisite optical and infra-red spectroscopy. With spatial fidelity more than ten times better than the Hubble Space Telescope and the James Webb Space Telescope these monumental observatories will allow us a god-like reach across our solar system. It is impossible to know exactly what we will see. Seasonal changes on Titan will be visible - and followed across decades - as will surface changes on Io, Europa, Ganymede, and even Enceladus around Saturn. Maybe we will witness rare but revealing phenomena. Perhaps one day Europa will crack, a chasm ten kilometers deep forming as the immense stresses of the Jovian gravitational tide wins out, and a watery soup will spill forth. As it sublimates and freezes, shutting this tear like all those scars before it, perhaps we will see not just the chemical signatures of a deep biosphere but strange organisms themselves, flopping to the surface in waves. Each freezing out but giving up their latent heat to the next, all reaching for photons and oxygen ions, favorite foods from the last harvest a thousand years before.
If Enceladus is indeed the rebuilt child of Saturn's rings, themselves the product of a long-since shredded moon, perhaps we will watch as it continues to twist and crack, shaking itself to some new equilibrium, at the same time providing a warm oasis for life far from the Sun. Even the cold dark Uranian and Neptunian systems will be far more accessible to us, and perhaps cryo-volcanically active places like Triton have unexpected goodies yet to be revealed.
Eventually Mars' daily globe will adorn our screensavers, a view not afforded by orbiting instruments, their cameras designed to probe only tiny patches. We will watch as yet another sandstorm rises and engulfs the planet, and marvel at the ephemeral delicacy of the icy environment. Perhaps here too we will enjoy watching the overlays that depict the migrations and flows of a newly discovered subsurface martian biosphere, probed and followed by fleets of wandering robotic avatars.
As comets venture through their perihelion, lighting our Earthly skies, these giant instruments will yield views previously the exclusive province of high-octane spacecraft flybys. The pocked and crumbly nuclei, some wet and spewing sublimated gases into space, others discrete but laden with rich organic chemistry, will all be routinely charted and examined for critical clues to the nature of solar system assembly and possibly the chemical mix that our planet started with some 4 billion years ago.
If there is one future wish, as we tumble into another stellar orbit, then it would be for such fidelity of cosmic vision, as well as the fidelity of terrestrial vision to recognize our common humanity. As the very stuff of stars, alive in an immense and ancient universe it would be a dreadful tragedy if we squander our moment in blindness.