Life Archives

September 21, 2022September 21, 2022 by Carolyn Collins Petersen

Habitable Planets Will Most Likely be Cold, Dry “Pale Yellow Dots”

An artist's concept of K2-18b, a super-Earth exoplanet that could support life. But, not all habitable planets are pale blue dots. Some are dry and yellow. Courtesy STScI

Remember all the habitable planets we’ve seen in science fiction movies? There’s wintry Hoth, for example, and overwhelmingly hot Dune. The folks in Interstellar visited an ocean world and a desolate rocky world. For all their differences, these places were still what they call on Star Trek M-class habitable worlds. Sure they weren’t all like Earth, but that made them excitingly alien for the lifeforms they did support. In the real universe, it seems that alien worlds not quite like ours could be the norm. Earth could be the real alien world.

September 21, 2022September 21, 2022 by Brian Koberlein

It Appears That Enceladus is Even More Habitable Than we Thought

Phosphorus is likely abundant in the waters of Enceladus. Credit: Southwest Research Institute

The problem with looking for life on other worlds is that we only know of one planet with life. Earth has a wondrous variety of living creatures, but they all evolved on a single world, and their heritage stems from a single tree of life. So astrobiologists have to be both clever and careful when looking for habitable worlds, even when they narrow the possibilities to life similar to ours.

September 13, 2022September 13, 2022 by Seth Lockman

Alien Artifacts Could Be Hidden Across the Solar System. Here’s how we Could Search for Them.

Galileo Project members (from left: Carson Ezell, Ezra Kelderman, Abby White, Alex and Lily Delacroix) with the audio tower (left), radar spectrum tower (middle) and radar imaging tower (right) behind them on the roof of the Harvard College Observatory. Image credit: The Galileo Project

Do aliens exist? Almost certainly. The universe is vast and ancient, and our corner of it is not particularly special. If life emerged here, it probably did elsewhere. Keep in mind this is a super broad assumption. A single instance of fossilized archaebacteria-like organisms five superclusters away would be all it takes to say, “Yes, there are aliens!” …if we could find them somehow.

July 15, 2022July 15, 2022 by Evan Gough

These Ancient Microbes Give a Glimpse of What Extraterrestrial Life Might Look Like

Rhodopsins are ancient proteins evolved by some of Earth's first life forms. They turned sunlight into energy without photosynthesis. Image Credit: Sohail Wasif/University of California, Riverside.

Will we discover simple life somewhere? Maybe on Enceladus or Europa in our Solar System, or further away on an exoplanet? As we get more proficient at exploring our Solar System and studying exoplanets, the prospect of finding some simple life is moving out of the creative realm of science fiction and into concrete mission planning.

As the hopeful day of discovery draws nearer, it’s a good time to ask: what might this potential life look like?

June 28, 2022June 28, 2022 by Carolyn Collins Petersen

Curiosity Finds Life-Crucial Carbon in Mars Rocks

Curiosity at Mt. Sharp, Gale Crater, Mars. To the left of the rover are two drill holes into the rocks "Aberlady" and "Kilmarie." Curiosity found high concentrations of clay in both rocks. Image Credit: NASA/JPL-Caltech/MSSS

We are carbon-based life forms. That means the basis for the chemical compounds that forms our life is the element carbon. It’s crucial because it bonds with other elements such as hydrogen and oxygen to create the complex molecules that are part of life. So, when we look for evidence of life elsewhere in the solar system, we look for carbon. That includes Mars.

May 18, 2022May 18, 2022 by Evan Gough

Maybe We Don’t Hear From Aliens Because They Choose To Go Silent

Artist impression of an alien civilization. Image credit: CfA

How will humanity meet its end?

That’s only a depressing question if you think that humanity will go on forever. Alas, nothing lasts forever, and if something could last forever, it probably wouldn’t be our struggling primate species.

But we’ll likely be around for a while yet, pondering things as we do. One of the things we love to ponder is: why don’t we hear from any other alien civilizations?

May 17, 2022May 18, 2022 by Carolyn Collins Petersen

Carbon-12 is an Essential Building Block for Life and Scientists Have Finally Figured Out How it Forms in Stars

Artist's impression of a red giant star. Their cores are cauldrons where carbon-12 is produced. — Artist’s impression of a red giant star. Their cores are cauldrons where carbon-12 is produced. Credit:NASA/ Walt Feimer

Each of us is, as it says in Max Ehrmann’s famous poem “Desiderata”, a child of the universe. It speaks metaphorically about our place in the cosmos, but it turns out to be a very literal truth. Our bodies contain the stuff of stars and galaxies, and that makes us children of the cosmos. To be more precise, we are carbon-based life forms. All life on Earth is based on the element carbon-12. It turns out this stuff is a critical gateway to life. So, how did the universe come up with enough of it to make you and me and all the life on our planet? Astrophysicists and nuclear physicists think they have an answer by using a supercomputer simulation of what happens to create carbon. As it turns out, it’s not very easy.

May 6, 2022May 5, 2022 by Paul M. Sutter

Scientists Create Molecules that can Follow Darwinian Evolution

photo of a turtle swimming underwater — Photo by Belle Co on Pexels.com

A team of researchers at the University of Tokyo have discovered a set of RNA molecules that are capable of replication and diversification. This potentially allows the molecules to undergo Darwinian evolution, pointing the way to a possible first step to life on Earth. As lead author Assistant Professor Ryo Mizuuchi said, “The results could be a clue to solving the ultimate question that human beings have been asking for thousands of years — what are the origins of life?”

May 4, 2022May 4, 2022 by Evan Gough

Hydrogen Gas Can Seep Through Rock Providing Food to Bacteria. Another Place to Look for Life On Other Worlds.

An artist’s interpretation of liquid water on the surface of the Europa pooling beneath chaos terrain. Credit: : NASA/JPL-Caltech

Spin Google Earth around until you’re looking down at the nation of Oman. Ancient rock in that country is the backdrop for a new study with consequences for our search for life. Water reacts with this rock to produce hydrogen, which could be an energy source for bacteria. Could this happen on other worlds?

April 27, 2022April 27, 2022 by Matt Williams

All Five of Life's Informational Components can Form in Space

On Earth, all life comes down to the polymeric molecules known as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These two building blocks contain all of the instructions for every living organism and its many operations. In turn, these are made up of five informational components (nucleobases), which are composed of organic molecules (purines and pyrimidines). For decades, scientists have been scouring meteorite samples for these building blocks.

To date, these efforts have resulted in the detection of three of the five nucleobases within meteorites. However, a recent analysis led by researchers from Hokkaido University, Japan (with support from NASA) has revealed the remaining two nucleobases that have eluded scientists until now. This discovery could help resolve the ongoing debate about whether life on Earth emerged on its own or was assisted by organic compounds deposited by meteorites (aka. panspermia).