For decades, science fiction writers have explored what extraterrestrial life might look like. From the imagined “little green men” to an amorphous consciousness, it’s hard to tell exactly what alien life might look like, when the only examples scientists have of life forming are here on Earth. But that doesn’t mean astrobiologists, or scientists who look for life off Earth, aren’t thinking about other possibilities. Microbes, rather than large organisms, could dominate life in the cosmos. Or maybe life can form from other chemical conditions – then, it might not be carbon-based, like life on Earth is.

One way to approach this topic, as University of Arizona astronomer Chris Impey explains, is to study complexity in chemical systems. If you define life as a self-sustaining chemical reaction that can evolve, you’ll want to understand what steps need to happen for that type of reaction to emerge from a collection of chemicals. As Impey writes, astronomers estimate there are “300 million potential biological experiments in our galaxy – or 300 million places, including exoplanets and other bodies such as moons, with suitable conditions for biology to arise.”

Also in this week’s science news:

One last note: My colleagues and I are able to find the scientists who are doing important and interesting research, and help them communicate their findings clearly to you, because of the support of readers like you.

Please donate to our end-of-year fundraising campaign if you find our articles to be informative and thought-provoking. Thank you.

Mary Magnuson

Associate Science Editor
Evolution, the process of change, governs life on Earth − and potentially different forms of life in other places. Just_Super/E+ via Getty Images

Extraterrestrial life may look nothing like life on Earth − so astrobiologists are coming up with a framework to study how complex systems evolve

Chris Impey, University of Arizona

A specific set of chemical conditions led to the emergence of life on Earth. But can life emerge from other chemistries?
Thawing permafrost and changing seasons affect wildlife across the Arctic. Dennis Welker/E+ via Getty Images

Arctic has changed dramatically in just a couple of decades – 2024 report card shows worrying trends in snow, ice, wildfire and more

Twila A. Moon, University of Colorado Boulder; Matthew L. Druckenmiller, University of Colorado Boulder; Rick Thoman, University of Alaska Fairbanks

Rapid changes underway in the Arctic affect the region’s people and wildlife, and the entire planet.
Although hypnosis can help with a number of medical conditions, it doesn’t work for everything. Paula Connelly/iStock via Getty Images Plus

Hypnosis is not just a parlor trick or TV act − science shows it helps with anxiety, depression, pain, PTSD and sleep disorders

David Acunzo, University of Virginia

Hypnosis is safe and can work as both a stand-alone or a complementary treatment with other therapies.

What is the universe expanding into if it’s already infinite?

Nicole Granucci, Quinnipiac University

The universe is constantly expanding, but how do scientists think about what it’s expanding into?

What is Salt Typhoon? A security expert explains the Chinese hackers and their attack on US telecommunications networks

Richard Forno, University of Maryland, Baltimore County

Chinese hackers are alleged to have broken into US phone networks, giving Chinese intelligence services a window onto specific Americans’ phone and messaging activity.

Adults grow new brain cells – and these neurons are key to learning by listening

Aswathy Ammothumkandy, University of Southern California; Charles Liu, University of Southern California; Michael A. Bonaguidi, University of Southern California

Understanding how new neurons affect brain function throughout adulthood can offer new approaches to treating epilepsy and dementia.

New set of human rights principles aims to end displacement and abuse of Indigenous people through ‘fortress conservation’

John H. Knox, Wake Forest University

Private conservation groups channel huge sums of money to parks and protected areas around the world, but often have failed to protect basic rights of Indigenous people living on those lands.