Category Archives: venus

astrobiology, venus

The Allure of Alien Life

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No doubt everyone reading this today has heard about the amazing discovery of phosphine in Venus’s clouds. It’s a chemical compound that can be made through industrial processes or via biological processes. Short of finding some kind of smog-filled industrial capital on the planet, it may be that some form of alien life is involved at Venus.

Artist's impression of Venus, where alien life may be creating phosphine.
This artistic impression depicts Venus. Astronomers at MIT, Cardiff University, and elsewhere may have observed signs of life in the atmosphere of Venus.
Image courtesy: ESO (European Space Organization)/M. Kornmesser & NASA/JPL/Caltech

BUT, and I want to stress this strongly, the presence is phosphine at Venus is not YET proof of alien life there. It’s a very strong signature. The scientists involved in the discovery have exhausted every avenue of study to figure out what’s producing phosphine there that isn’t a form of life. So, like good scientists, they have announced their findings and now await confirmation by other scientists of their conclusions.

As Dr. Clara Sousa-Silva of MIT said (and she’s studied phosphine for years), “It’s very hard to prove a negative. Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine.”

I hope this engenders a lot of work for scientists, because the discovery of life elsewhere in the universe is an important step forward. So, they need to do it right. And, I know they will.

Finding alien life has been a driver for the science astrobiology. Heck, it’s been a driver in astronomy. Who hasn’t looked up at night and wondered if somebody else is “out there”, looking back at us? So yeah, the allure of finding life on other worlds has been with us for a long, long time.

The Allure of Venus’s Alien Life

So, what kind of life would create phosphine? Where would it “live” on Venus. The most likely life-bearing region on the planet is actually in its atmosphere. There’s a fairly temperate zone ranging between 45 and 60 kilometers above the surface. It’s a place where the temperatures lie in a range between 20 and 200 degrees F. That’s not a bad temperature range for extremophile life forms, the kind that think boiling water is a great place to live or where cold temperatures are just a cool day.

However, there’s a lot of sulfuric acid in Venus’s clouds, and that’s not so great for any kind of life. No even some tough little microbes. So, there is a “Goldilocks zone” of sorts in the Venus atmosphere where air-borne microbial life could exist, even if it has to deal with acidic droplets.

What Would Venus Alien Life Look Like?

Yesterday, on the Space Hangout, we all talked about the possibility of such life. Fraser Cain suggested that one way it could exist would be that it hides out in water droplets, and then sporulates as it drops through the atmosphere. The spores would be hardened against the acidic environment, get blown back up to the “Goldilocks Zone”, where they’d sprout, live, and then start the whole process over again.

That’s certainly one way to do it. But, I suspect there are others. And, knowing planetary scientists and astrobiologists, we’re bound to see some pretty interesting suggestions come out. However, first everybody has to work through all the possibilities of the types of life that could be making the phosphine. Then, they’ll have to figure out the chances of such things actually existing. It’s going to be an exciting time in both sciences! Stay tuned!

hot Jupiters, venus

Hot Planets are Out There!

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Last week I did a “Skype-in” session with a group of students in Midland, Texas. They were doing a special science unit on space. As expected, I got a LOT of questions during the session about black holes, Pluto, and—interestingly enough, one about how much a SpaceX rocket costs to build. But, there was one about hot planets, and that got me thinking and searching to find out which is the hottest planet.

You’d think that’d be an easy answer. In one sense, it is, but only if you are thinking of our own solar system. Venus has the hottest surface temperatures of any world circling the Sun. They get up to nearly 500°C or 800° F. That’s pretty darned hot, and coupled with the very high atmospheric pressure from all those clouds, make the planet a very inhospitable place.

Venus as seen by Magellan
Venus as seen by Magellan spacecraft. Radar scans made by the mission showed areas where lava has flowed in the past from mountains and other vents. We do not see the clouds that shroud Venus since the radar “cuts” right through them. But, they trap heat on the surface. Courtesy NASA

Another Way to Look at Hot Planets

If you broaden the definition of “hot planets” and use our galaxy as a search region, then there are hotter planets out there. They’re called “hot Jupiters” and they can get up to nearly 4,300°C (7,800°F). I’ve written about them before, including an intriguing report about water at these planets. Hot Jupiters are at least as massive as our own Jupiter and are often many times more than that. Astronomers recently reported on one that they discovered called KELT-9B.

The research team, which included Megan Mansfield of the University of Chicago, used the Spitzer Space Telescope to study the star and try to figure out what’s happening with it. KELT-9b is an “ultra-hot” Jupiter orbiting a star about 670 light-years away. It was first discovered by the Kilodegree Extremely Little Telescope (KELT) system based in Arizona and South Africa. The planet is not just like our Jupiter—it’s even weirder. It’s among the hottest worlds ever found. While it orbits its star, KELT-9b goes through these strange meltdowns. Things get so hectic during those events that gas molecules in the atmosphere get torn apart.

Why is a Hot Planet So Chaotic?

That’s a good question. The best models about hot planets, and this one, in particular, suggest that extreme heat plays a role. It’s at least partly to blame for the chaos that rips apart the atmospheric gases. How does it happen? The planet spins on its axis (just as Earth does). It takes 1.5 days to make one trip around its star (which basically gives it a 1.5-day “year”). That arrangement means that the planet shows the same “face” to its star all the time. It’s “locked” into doing so. However, the gases in the atmosphere do flow around the planet.

So, what happens? When the gases on the “day” side of the planet get superheated, the hydrogen molecules get shredded. Then, as that material flows around to the night side, everything cools down, and the gas reassembles itself. That is, at least, the working hypothesis that the scientists who study this star are using to explain its strangeness.

KELT-9b orbits its star and as it does, extreme heat rips apart molecules in its atmosphere.
Artist’s rendering of a “hot Jupiter” called KELT-9b, the hottest known exoplanet – so hot, a new paper finds, that even molecules in its atmosphere are torn to shreds. The planet is the smaller object orbiting the hot, blue star. Credit: NASA/JPL-Caltech

So, to give a more accurate answer to the students from Midland, Venus is truly the hottest planet in our solar system. BUT, our galaxy has even hotter ones out there. KELT-9B may be just one of many of the thousands of planets astronomers have found so far.