What's been happening of astrobiological interest in the last couple of weeks?
Planet 9 cast into doubt?
A project known as the Outer Solar System Origins Survey (OSSOS) has presented data on four new outer solar system objects that appears to be inconsistent with proposals for a large planet some 500 to 700 astronomical units from the Sun. Those earlier proposals hinge on the apparent 'clustering' of the orbital shapes of other distant bodies; an arrangement that could be explained by the presence of a large orbit 'super-Earth' or 'mini-Neptune' scale world, hitherto unseen. But the OSSOS researchers suggest that observational biases could be spoofing the apparent orbital clustering. It's too early to dismiss Planet 9, but these results demonstrate the enormous challenge of studying even our own planetary system.
Yet another outer planet?
While Planet 9 continues to intrigue, another set of data on 600 objects in the outer solar system appears to indicate the presence of a roughly Mars-mass object perturbing material in the Kuiper belt (planet 8.1?). Specifically, the more distant of these icy bodies have orbits that are on average inclined or warped with respect to the primary or 'invariable' plane occupied by the major planetary bodies. What could cause this? The gravitational pull of a planet-sized body roughly 60 astronomical units from the Sun and with its own orbit tilted by about 8 degrees would do the trick.
Planetary protection leads to sweaty skin Archaea
A study that began by looking at spacecraft clean-room microbial contamination has led to an investigation of what lurks on human skin. A species of archaea called Thaumarchaeota started showing up in clean room samples, and researchers tracked the source down to the human epidermis. This is surprising because archaea have not generally associated with the skin microbiome. This particular species may be involved in the processing of nitrogen from human sweat (through ammonia oxidization). Once again, microbial life demonstrates how it will occupy any available niche, from planetary surfaces to human surfaces.