Red dwarfs make up the vast majority of stars in the galaxy. Such ubiquity means they host the majority of rocky exoplanets we’ve found so far—which in turn makes them interesting for astrobiological surveys. However, there’s a catch—astrobiologists aren’t sure the light from these stars can actually support oxygen-producing life. A new paper, available on the arXiv preprint server, by Giovanni Covone and Amedeo Balbi, suggests that they might not—when it comes to stellar light, quality is just as important as quantity. And according to their calculations, Earth-like biospheres are incredibly difficult to sustain around red dwarfs.

Life’s capacity to survive in simulated lunar and Martian soils has been explored in two papers published in Scientific Reports. Treating simulated lunar soil with both symbiotic fungi and worm-produced compost can significantly improve the likelihood of reproduction for chickpea plants growing in the soil, indicates one study. A separate paper suggests that some microbes may be able to absorb enough water from the atmosphere to grow in simulated Martian soil at atmospheric humidity levels comparable to those on the planet.

Ever since physicist Freeman Dyson first proposed the concept in 1960, the “Dyson sphere” has been the holy grail of techno-signature hunters. A highly advanced civilization could build a “sphere” (or, in our more modern understanding, a “swarm” of smaller components) around their host star to harvest its entire energy output. We know, in theory at least, that such a swarm could exist—but what would it actually look like if we were able to observe one? A new paper, available on the arXiv pre-print server and soon to be published in Universe from Amirnezam Amiri of the University of Arkansas, digs into that question—and in the process discloses the types of stars that are the most likely to find them around.