The Dark Side of Biology

Life on the primordial Earth got started early. The oldest microfossils—found by a British team in Canada—may date back as far as 3.8 billion years and were probably living on the ocean floor at a volcanic vent. Other organics rained from the sky, brewed by lightning or solar radiation. © Michael Carroll

Gene Roddenberry populated his Star Trek universe with a wide variety of aliens. Budget constraints dictated that most were variations of humans, with skin tinted odd colors or antennae sticking out from their heads. Even the silicon-based Horta appeared to be a stagehand lurking under a decorated carpet. George Lucas treated us to a similar menagerie of off-world inhabitants in Star Wars, especially in his Mos Eisley Cantina. Aliens—and our concept of them—became more sophisticated as budgets soared and science grappled with the great question posed by Enrico Fermi: “Where is everybody?” Some were terrifying, like the creatures in the Alien movie series or H. G. Wells’s conspiring Martians in War of the Worlds. Perhaps our propensity for seeing extrasolar life as terrifying is our natural fear of the unknown. But others were far more benign and advanced, as witnessed by Arthur C. Clarke’s 2001: A Space Odyssey, Steven Spielberg’s cuddly E.T., Edmund H. North’s guardians of the worlds in The Day the Earth Stood Still, or the time-jumping beings of Eric Heisserer’s Arrival. But at the heart of a good story is a good conflict, and aliens provide natural fodder for such a plot device.     READ MORE...

Super Earths Are Common

Astronomers now routinely discover planets orbiting stars outside of the solar system – they’re called exoplanets. But in summer 2022, teams working on NASA’s Transiting Exoplanet Survey Satellite found a few particularly interesting planets orbiting in the habitable zones of their parent stars.

One planet is 30% larger than Earth and orbits its star in less than three days. The other is 70% larger than the Earth and might host a deep ocean. These two exoplanets are super-Earths – more massive than the Earth but smaller than ice giants like Uranus and Neptune.

I’m a professor of astronomy who studies galactic cores, distant galaxies, astrobiology and exoplanets. I closely follow the search for planets that might host life.

Earth is still the only place in the universe scientists know to be home to life. It would seem logical to focus the search for life on Earth clones – planets with properties close to Earth’s. But research has shown that the best chance astronomers have of finding life on another planet is likely to be on a super-Earth similar to the ones found recently.  READ MORE...

5,000 Worlds Outside

In January 1992, two cosmic objects forever changed our galaxy.

For the first time, we had concrete evidence of extrasolar planets, or exoplanets, orbiting an alien star: two rocky worlds, whirling around a star 2,300 light-years away.

Now, just over 30 years later, that number has exploded. This week, March 21 marked the hugely significant milestone of over 5,000 exoplanets confirmed. To be precise, 5,005 exoplanets are now documented in the NASA exoplanet archive, every one with its own unique characteristics.

Each and every one of these exoplanets has appeared in peer-reviewed research, and been observed using multiple detection techniques or methods of analysis.

The pickings are rich for follow-up study to learn more about these worlds with new instruments, such as the recently launched James Webb Space Telescope, and upcoming Nancy Grace Roman Space Telescope.

"It's not just a number," says astronomer Jessie Christiansen of the NASA Exoplanet Science Institute at Caltech. "Each one of them is a new world, a brand-new planet. I get excited about every one because we don't know anything about them."  READ MORE...