[BRIEF NOTE] On the sadness of astronomical truths revealed.

[rfmcdonald]

Centauri Dreams reports that our solar system, with rocky planets close to their star and gas giants far away, is rare.

[Astronomer Scott]Gaudi’s team has concluded that about fifteen percent of the stars in the galaxy are orbited by planetary systems like our own, meaning they have several gas giants in the outer part of the solar system. That fifteen percent is telling. “Solar systems like our own are not rare,” says Gaudi, “but we’re not in a majority, either.” Microlensing is useful for this kind of study because the method does a good job at picking up giant planets far from their primary star, a more difficult task with Doppler methods.

Working with colleague Andrew Gould, Gaudi used four years of MicroFUN data and folded in a statistical analysis based on ‘robust assumptions’ and the earlier work of both men. It turns out that MicroFUN in that period of time has revealed precisely one solar system with two gas giants in roughly the configuration of Jupiter and Saturn. Statistically, if every star had a solar system like ours, we should have found about six such systems by now. The slow discovery rate implies only a small number of systems have our configuration, no more than about fifteen percent.

[. . .]

[G]iven the number of stars in the galaxy, even narrowing the odds down to fifteen percent leaves several hundred million systems that could resemble ours. Nor should we assume that a system necessarily has to mimic our own for life to develop within it. Nonetheless, this is an intriguing result that reinforces our sense that extrasolar planetary systems come in a surprising variety, one we learn more about with every new detection.

Andrew Barton's thoughts are worth noting.

The stars beyond Sol have been ciphers for all of human history - for almost all of the time that science fiction has been written, Earth's intrepid explorers might find anything under other suns.

This decade might see this change a bit. NASA's Kepler telescope, launched last March on a multi-year mission to discover strange new worlds, has been hard at work, and on Monday details were released of the five new exoplanets detected by its efforts. All five of the newfound planets are hot worlds, orbiting extremely close to their parent stars, and only one is smaller than Jupiter. Going back to the discovery of Bellerophon in 1995, many of the exoplanets so far detected have been such "Hot Jupiters." Kepler is poised to change that, with its sensitive instruments said to be capable of detecting Earth-mass planets orbiting other stars. Not only that - in the near future, telescopes may well be able to detect individual moons orbiting these gas giants. Presumably, only the exotic properties of the mass relays will prevent Kepler from detecting them as well.

While this is great news to me, as a scientifictionist it poses a problem for the immediate future. Back in 1940, spaceflight itself was widely considered a fool's dream - whether or not Mars had canals and Venus jungles, if the writers of the time were concerned about accuracy, for all they knew it might have been a hundred years until they were proven wrong or right either way. I feel like I'm in a similar place now as to when Larry Niven wrote and sold The Coldest Place in 1964, written when the leading consensus was that Mercury was tidally locked, a consensus that was only broken by radar mapping - and after The Coldest Place had been bought, but before it was published.

[. . .]

Kepler, if successful, will revolutionize our understanding of the interstellar neighborhood. In ten years, maybe we'll know that a planet of Tau Ceti or a moon of a gas giant at 55 Cancri has an oxygen-nitrogen atmosphere and liquid water. We wouldn't be speculating blind anymore.

I'm not a published writer (yet?), but I am heavily involved in the onliny 2300AD/2320 community. This roleplaying game universe is hardish science fiction, the game universe using only real stars in their proper locations as best was known in the late 1980s. I'm participating in the Tirane Sourcebook project, an effort to detail the heavily populated Earth-like world of Tirane orbiting Alpha Centauri A. I've written an extensive article about Neubayern, the name for the Groombridge 1618 planetary system that hosts the heavily-populated Earth-like if tidelocked world of Nibelungen. I could once write these knowing that, maybe, worlds like these might exist orbiting those stars and in any case there'd be no way of finding out otherwise. That's not the case now.

It'll be wonderful to find out what's out there, of course, but still, I can't help but feel a bit of sadness at waking up from those dreams.