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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!

Ever since the first extrasolar planets were found in the mid-1990s, we’ve been fascinated by what they could be like. Of course, we hope to find rocky worlds. And, astronomers have found gas- and ice-giant worlds. But, how about diamond planets?

As a science fiction reader, I’ve “visited” many strange planets throughout the years. Heinlein wrote a story about Venus as a sloppy, hot, wet hellhole. He had people living and working there. The astronomer Carl Sagan and others thought that Jupiter’s clouds could possibly host strange life forms suited to the conditions there.

Weird Planets in Science Fiction

I remember reading with great fascination in Arthur C. Clarke’s Childhood’s End about one character’s exploration of worlds with high gravity, where aliens flitted about with wings. He also described another world that hosted a weird bit of life in the shape of a giant eye. It was pretty clear that the planets shaped the life forms.

That makes sense, once you understand how stars and planets form. Their birthplaces are giant clouds of dust and gas. The resulting objects orbiting the star are going to have the same “bulk composition” as their birth cloud. If the cloud is like the one our solar system was born in, it has a much lower ratio of carbon to oxygen. Plus, as we know from Earth, it had more silicates. That is, in fact, the general composition of Earth. It does have carbon—in smaller abundance.

Could There be Carbon Planets?

A group of scientists at Arizona State University and the University of Chicago took a look at the types of known planets. Their goal was to figure out if a carbon-rich planet could exist. If so, that might imply the existence of diamond planets.

Thanks to the Kepler and Tess missions, along with Hubble Space Telescope, and a slew of ground-based observations, we know that, as of today, (according to the NASA Exoplanet Archive) 4,276 of these discoveries are confirmed as exoplanets. There are thousands more candidates that have to be confirmed. The hunt for planets is a slow and painstaking process, and I’m sure astronomers will be finding and confirming more.

A carbon-rich planet like WASP-12b could be compressed by heat and temperature to become a diamond planet. — This artist’s concept shows the searing-hot gas planet WASP-12b (orange orb) and its star. NASA’s Spitzer Space Telescope discovered that the planet has more carbon than oxygen, making it the first carbon-rich planet ever observed. Our planet Earth has relatively little amounts of carbon. It is made largely of oxygen and silicon. Concentrated carbon can take the form of diamond, so carbon-rich gas planets could have abundant diamond content in their interiors. WASP-12b is located roughly 1,200 light-years away in the constellation Auriga. Credit: NASA/ Robert Hurt.

The current missions and observations are giving astronomers a pretty good look at what the known planets are made of. They also get a good idea of what they might look like, plus some clues about whether or not they could be habitable. What if the proto-stellar nebula has more carbon in it? Then, you might expect to see carbon-rich planets.

Making Carbon/Diamond Planets in the Lab

The research teams devised an experiment to simulate how such planets might form. They mimicked the interior of carbide exoplanets using high heat and high pressure in the lab, using high-pressure diamond-anvil cells. First, they immersed silicon carbide in water and compressed the sample between diamonds to a very high pressure. Then, to monitor the reaction between silicon carbide and water, they conducted laser heating at the Argonne National Laboratory in Illinois. They took x-ray measurements while the laser heated the sample at high pressures. The result? With high heat and pressure, the silicon carbide reacted with water and turned into diamonds and silica.

So, if conditions are right (meaning ample amounts of water, silicates, and carbon), it’s possible that the universe could be creating carbon-rich planets made of diamonds and silica.

Life on a Diamond Planet?

So, what if a planet is made of diamonds? Could it support life? That’s an excellent question, and so far, nobody has found life of any kind on other worlds. But, life is tenacious, and it doesn’t have to live on a planet just like Earth. However, a carbon planet might be stretching it a bit. Having a planet made mostly of compressed carbon, a diamond planet, can pose new problems for life.

Planetary scientists and astrobiologists are hoping to find planets with the right properties. They also have to be at the right location around their stars so life could exist. So far, however, nada. And, it gets worse for carbon-rich planets. They likely do not have the properties needed for life. Why would that be?

A Diamond Planet Compared to Earth

Earth life grew up in conditions unique to Earth. Our planet is geologically active (an indicator of habitability), for one thing. If the results of this study work for actual carbon-rich planets, then they are too hard to be geologically active. Without geologic activity, it’s tough to build up an atmosphere to support life. The planets may not meet all the requirements that living creatures need. It doesn’t necessarily mean that there isn’t a carbon-rich planet out there teeming with some kind of life. However, the odds are stacked against it.

Still, imagine a diamond planet! I remember goggling at the idea of a diamond core in Jupiter. I read about THAT in one of Clarke’s books). So, it’s not so far-fetched to think about a diamond world somewhere out there. It could be orbiting a distant star, along with its rocky and gas/ice giant siblings.

The Spacewriter's Ramblings

The Allure of Alien Life