Kuujjuarapik Kritters
There’s news today that Hudson’s Bay could help us detect life on distant worlds. (No, not the Hudson’s Bay Company but the actual body of water in northern Canada.) A challenge for detecting life on exoplanets is that we actually can’t go there and dig around for signs. Instead, we have to look for the signatures of life in the light from the exoplanets, e.g., that reflected by the planet’s surface in which some small parts will be absorbed by the chemicals known to be involved with life. Exactly what to look for in the spectra has been not so clear but recently a team of scientists has worked to develop a guide-book of possible microbial signatures. Specifically, they collected ice core samples in the mouth of the Great Whale River (Grande rivière de la Baliene) near Kuujjuarapik, Quebec, isolating 80 different microbes. (Warwick Vincent, the Canada Research Chair in Aquatic Ecosystem Studies at Laval University was involved.) These “kritters” were then grown in a lab at Cornell University state and then “observed” in another Cornell lab to see what a telescope would see if similar critters inhabited the surface of an icy exoplanet. The results were then used to create a database of spectroscopic signatures of microbial life. In particular, they note that carotenoid signatures (i.e., from red, orange, and yellow pigments) are “quite intriguing” as indicators of life because they are seen in a wide range of microbes. Furthermore, they predict from their data that signatures from such microbes may be easier to see in drier environments, e.g., the surfaces of icy worlds. Hopefully, the current and future missions that will be exploring the spectra from distant exoplanets will use this database to investigate and interpret their data. Here’s a link to the Astrobiology paper, so you can see the abstract. We don’t have an online subscription to this journal but perhaps the paper can be requested by NRC’s Science Library.
Meanwhile, also earlier this month, a study was released where the possibilities of microbial life were assessed for locations in our Solar System beyond the Earth. The team involved in this work concocted a “Microbial Habitability Index” that combines various microbial survival factors relative to the Earth, and was then used to determine that the best locations to look for microbial life are Jupiter’s moon Europa, the planet Mars, and Saturn’s moon Enceladus. (Five other Solar System locations were also identified as being primary candidates for life.) Since space missions aren’t cheap, it really helps to know where to look! Here’s a link to the arXiv preprint about this study for those who want more information.
Finally, NASA has announced another key Webb milestone today: the completion of the “fine phasing” step in Webb’s ongoing mirror alignment campaign. For this step, residual alignment errors after course phasing were measured and corrected using the same defocusing method used for the original segment alignment but instead of using the secondary mirror as before some optical elements in the instruments were used (in this case, NIRCam). Webb’s optical performance is apparently already meeting or exceeding its original specifications! Attached is an image showing the aligned optics – note all the galaxies in the image that were easily detected! (That star in the centre is 2MASS J17554042+6551277.) Also, the alignment team has not found any critical issues or blockages along the path that light travels through the telescope and NIRCam. Meanwhile, alignment of Webb’s other three instruments and eliminating any residual pointing errors will come in the weeks ahead. Here’s a link to the NASA press release about this milestone. Thanks to Wes Fraser for the tip-off of this story earlier today!