Cav's Place

Since I was looking at Opportunity‘s latest self-portrait when the big news hit yesterday, I’ll start this post with the second part of the title and say that bright days sure seem to be ahead for the little rover, and not only because it made it through its sixth Martian winter. Strangely enough, the update covering March 20 to 27 is missing from the archive and the pictures that form that image were taken between March 22 and 24, so I don’t know what the dust factor, which measures the percentage of sunlight that gets through the layer of dust and reaches the solar panels, was at that point, but it was reported as 0.777 on March 19 and 0.868 on April 1. This latter value seems to be the highest since this measurement started being reported, in 2007, and it certainly is a whole lot better than it was when the previous self-portrait was taken, between January 3 and 6, the dust factor reported on January 7 being 0.555. Then again, even that was an improvement at the time, as it was reported to have reached as low as 0.467 on December 5, which was a value not seen since February 14, 2012.
I still find myself in some way attached to that little rover, while at the same time largely ignoring Curiosity, largely due to the latter’s nuclear power source. Since space exploration should make use of the best technology we have available, I find that moving back away from solar power instead of making use of the opportunity to push the technology to its limits and improve it even further sends the wrong message here on Earth, not to mention that it carries a risk, no matter how small or irrelevant, of contaminating another world. As such, if little else, I at least hope that Opportunity will, however briefly, end up holding the record for the longest distance covered by a vehicle anywhere other than on Earth, even though the Russians made a point of moving that goal.

As for yesterday’s big announcement, it’s undeniable that finally being able to confirm the first Earth-size exoplanet within its star’s habitable zone is a major achievement. The previous best find was 40% larger than Earth, while Kepler-186f is estimated as probably being only 11% larger, with other possible values ranging between 2% smaller and 25% larger, so it’s certainly Earth-size, seeing as this is defined as being between 20% smaller and 25% larger than Earth. Granted, it’s at the outer edge of the habitable zone, the average temperature calculated according to a standard model that ignores atmosphere being a frigid 180°K, but a sufficient amount of greenhouse gases would easily allow for liquid water to exist on the surface, not to mention that other processes may cause the temperature to be above freezing in the depths of any oceans that may exist. As such, it may not necessarily be the single best suited for life as we know it out of all the exoplanets we have found so far, but it’s definitely a huge step in the right direction in our search.
A study about the formation, tidal evolution and habitability of the Kepler-186 system has also been submitted and, if you’re in any way interested in the topic, you definitely should read it. Not counting the references, it only has 13 pages and it is currently the best source of answers to many for the common questions people may have. In short, it says that, while it is currently argued that planets in such systems should be relatively dry and, in addition, Kepler-186f either already is or is on its way to becoming tidally locked to its star, it definitely has the potential to be habitable according to our current definition of the term, though the degree of uncertainty is relatively high due to the lack of data.
Perhaps more importantly, however, the study also stresses that simulations confirm something that is also obvious if you simply look at the distances, namely that at least one other planet, and probably two, should have formed between Kepler-186e and Kepler-186f, so in the warmer part of the star’s habitable zone. It is, of course, possible that the planet or planets in question have been destroyed by impacts or thrown out of the system, but if they still exist then their masses should probably not exceed that of Earth, because otherwise their influence would have made the transits of the five we do know of, and of the one announced yesterday in particular, unlikely. As such, the system itself may be even more interesting than it currently appears, seeing as the conditions on those potential planets would probably be even more suitable for life as we know it, though at the same time the existence of such a planet or planets would actually reduce the likelihood of Kepler-186f being habitable.

Overall, I’ll go as far as saying that yesterday was an important day for mankind. Of course, many don’t see the true significance of the knowledge gathered and I could only sigh and shake my head at many of the comments and questions posted by some people on the Kepler Mission‘s Facebook page. The mission’s purpose was to see whether other Earth-size planets exist in their stars’ habitable zone and, if so, to get a rough idea of how common they are, plus of course to get a rough idea of how common planets of all types are in general. With this confirmation, that first goal was reached, and that’s a great achievement in itself! Anything else is, at this point, science fiction… And will unfortunately remain so for a long time if space exploration will continue to be as low of a priority and receive as little funding as it currently does.