Last week, an incredible announcement was made about the search for extraterrestrial life: Phosphine gas detected in the clouds of Venus – a potential indicator of life or “biosignature.” Now some gases might be a false positive for biosignatures because they can be created by other chemical processes on a planet like photochemical processes in the atmosphere or geological processes beneath the surface that create a given gas. For example, methane can also be a biosignature, and we’ve been hunting it down on Mars, but we know that methane can also be created geologically. Finding phosphine in Venusian clouds is truly remarkable because we don’t presently know of any way to create phosphine abiotically or without life being a part of the equation. Question is – how much life??
The discovery of phosphine in the upper clouds in Venus’ atmosphere has generated a lot of excitement. On Earth, phosphine is produced biologically, so it’s a sign of life. If it’s not produced by life, it takes an enormous amount of energy to be created abiologically.
On other planets like Jupiter, there’s enough energy to produce phosphine, so finding it there isn’t surprising. But on a small rocky world like Venus, where there’s no powerful source of energy, its existence is surprising.
Scientists have learned a lot about the atmospheres on various worlds in our Solar System simply from planetary sunrises or sunsets. Sunlight streaming through the haze of an atmosphere can be separated into its component colors to create spectra, just as prisms do with sunlight. From the spectra, astronomers can interpret the measurements of light to reveal the chemical makeup of an atmosphere.
Astronomers have painstakingly built models of the asteroid population, and those models predict that there will be ~1 km sized asteroids that orbit closer to the Sun than Venus does. The problem is, nobody’s been able to find one. Until now.
Astronomers working with the Zwicky Transient Facility say they’ve finally found one. But this one’s bigger, at about 2 km. If its existence can be confirmed, then asteroid population models may have to be updated.
A team of scientists has just published a paper announcing their discovery of a peculiar chemical in the cloudtops of Venus. As far as scientists can tell, this chemical, called phosphine, could only be produced by living processes on a planet like Venus. So the whole internet is jumping on this story.
But did they find signs of life? Or is there another explanation?
Venus has been garnering a lot of attention lately, though primarily in the scientific community as the last Hollywood movie about the planet was released in the 1960s. This is in part due to its dramatic difference from Earth, and what that difference might mean for the study of exoplanets. If we can better understand what happened during Venus’ formation to make it the hell scape it is today, we might be able to better understand what truly constitutes the habitable zone around other stars.
Numerous planetary scientists have focused on Venus’ formation and atmospheric development in the recent past. Now a new paper posits that Venus might have had liquid water on its surface as recently as one billion years ago. And a contributor to the disappearance of that water might be an unlikely culprit: Jupiter.
When it comes to places with the potential for habitability, Venus isn’t usually considered on that list. The hot, greenhouse-effect-gone-mad neighboring planet with a crushing surface pressure and sulfuric acid clouds certainly isn’t friendly to life as we know it, and the few spacecraft humanity has sent to Venus’ surface have only endured a few minutes.
But up about 40 to 60 km (25 to 37 miles) above the surface, the atmosphere of Venus is the most Earth-like of any other place in the Solar System. There, Venus has air pressure of approximately 1 bar and temperatures in the 0°C to 50°C range. It’s not quite a shirtsleeves environment, as humans would need air to breathe and protection from the sulfuric acid in the atmosphere. Plus, also consider that Venus is considered to be in the habitable zone of our star.
Every 26 months, the orbits of both Earth and Mars conspire to make travel between the two planets shorter. Launching in one of these windows means the travel time can be reduced to only six months. Our robotic missions to the Martian surface, and missions that place satellites in Martian orbit, launch during these windows.
But are there other alternatives to this mission architecture?
One group of researchers says that crewed missions to Mars shouldn’t go directly to their destination; they should slingshot past Venus first.