Europa Clipper is scheduled to launch on October 10, with arrival at Jupiter in 2030. That will keep subsurface oceans on our minds as we tangle with the problems of analyzing water locked under kilometers of ice. Some moons, of course, help us out. Enceladus spews watery materials into space through cracks in its crust, making flybys through its geysers a possibility for snagging samples. Europa Clipper may find further evidence of the much less dramatic plume activity that has been spotted on Europa. Clipper’s SUrface Dust Analyzer (SUDA) would prove vital in such analysis. If cellular material is found in an ice grain snared from an orbital pass, would we be able to detect it? The answer may be found in laboratory work with a common bacteria that thrives in the waters off Alaska. As explained in new work out of the University of Washington and the Freie Universität Berlin, the bacterium Sphingopyxis alaskensis is made to order for such studies. It is smaller than Escherichia coli...

Just a few weeks ago I wrote about stellar interactions, taking note of a concept advanced by scientists including Ben Zuckerman and Greg Matloff that such stars would make for easier interstellar travel. After all, if a star in its rotation around the Milky Way closes to within half a light year of the Sun, it’s a more feasible destination than Alpha Centauri. Of course, you have to wait for the star to come around, and that takes time. Zuckerman (UCLA), working with Bradley Hansen, has written about the possibility that close encounters are when a civilization will attempt such voyages. I have a further idea along the lines of motion through the galaxy and its advantages to explorers, and it’s one that may not require tens of thousands of years of waiting. We’d like to get to another star system because we’re interested in the planets there, so what if an interstellar planet nudges into nearby space? I’ll ignore Oort Cloud perturbations and the rest to focus on a ‘rogue’ or...

Planet formation is a fascinating subtopic of the exoplanet hunt, and it may just have produced the first exoplanet detection in data that go back as far back as 1981, though the event in question has never been confirmed as being caused by a planet. I learned this through a paper sent me recently by Jean Schneider (Observatoire de Paris), who along with colleague Danielle Briot wrote about the early days of transit searches in a chapter for the Handbook of Exoplanets (Springer, 2018). I want to dig deeper into that chapter in a later post, but for now, I note that the planet Beta Pictoris b, discovered in 2008 and orbiting an infant star 63 light years from Earth, may have transited in 1981, according to subsequent papers on the matter. The debris disk around the primary has long fascinated astronomers and it has been investigated for the possible presence of comet-like bodies and subjected to direct imaging searches, which revealed Beta Pictoris b and confirmed it in 2009. But the...

I'm going to start in the Kuiper Belt this morning before going further out, because the news that the Belt may extend much further than expected reminds us of the nature of exploration. The New Horizons spacecraft, well beyond Pluto’s orbit and approaching 60 AU from the Sun, is finding more dust than expected. Our theoretical models didn’t see that coming. In fact, the dust produced by collisions between Kuiper belt objects was thought to decline as we approached the Belt’s outer edge. So just where is that outer edge? It had been pegged around 50 AU but now looks more like 80 AU, if not further out, a finding corroborated by the fact that New Horizons scientists have used Earth-based resources like the Subaru Telescope in Hawaii to find numerous KBOs beyond the assumed boundary. Is this a new population of Solar System objects, or are we actually seeing something more mundane, such as radiation pressure pushing inner belt dust further out than would be expected? It takes patient...

Some things just run in families. If you look into the life of Otto Struve, you’ll find that the Russian-born astronomer was the great grandson of Friedrich Georg Wilhelm von Struve, who was himself an astronomer known for his work on binary stars in the 19th Century. Otto’s father was an astronomer as well, as was his grandfather. That’s a lot of familial energy packed into the study of the stars, and the Struve of most recent fame (Otto died in 1963) drew on that energy to produce hundreds of scientific papers. Interestingly, the man who was director at Yerkes and the NRAO observatories was also an early SETI advocate who thought intelligence was rife in the Milky Way. Of Baltic-German descent, Otto Struve might well have become the first person to discover an exoplanet, and therein hangs a tale. Poking around in the history of these matters, I ran into a paper that ran in 1952 in a publication called The Observatory titled “Proposal for a Project of High-Resolution Stellar Radial...

Our recent conversations about the likelihood of life elsewhere in the universe emphasize how early in the search we are. Consider recent work on TRAPPIST-1, which draws on JWST data to tell us more about the nature of the seven planets there. On the surface, this seven-planet system around a nearby M-dwarf all but shouts for attention, given that we have three planets in the habitable zone, all of them of terrestrial size, as indeed are all the planets in the system. Moreover, as an ultracool dwarf star, the primary is both tiny and bright in the infrared, just the thing for an instrument like the James Webb Space Telescope to harvest solid data on planetary atmospheres. This is a system, in other words, ripe for atmospheric and perhaps astrobiological investigation, and Michaël Gillon (University of Liége), the key player in discovering its complexities, points in a new paper to how much we’ve already learned. If its star is ultracool, the planetary system at TRAPPIST-1 can also be...