Life Archives

September 27, 2023September 27, 2023 by Evan Gough

Even Tiny Amounts of DNA on Mars Will Be Detectable

The Perseverance Mars rover took this selfie with several of the 10 sample tubes it deposited on the Image Credit: NASA/JPL-Caltech/MSSS.

The Search for Life is focused on the search for biosignatures. Planetary life leaves a chemical fingerprint on a planet’s atmosphere, and scientists are trying to work out which chemicals in what combinations and amounts are a surefire indicator of life. Martian methane is one they’re puzzling over right now.

But new evidence suggests that super-tiny amounts of DNA can be detected in Martian rocks if it’s there. And though it requires physical samples rather than remote sensing, it’s still an intriguing development.

September 18, 2023September 18, 2023 by Evan Gough

When did the First Continents Appear in the Universe?

Continents might be necessary for life, especially complex life. This image shows super-continent Pangaea during the Permian period (300 - 250 million years ago). Credit: NAU Geology/Ron Blakey

On Earth, continents are likely necessary to support life. Continents ‘float’ on top of the Earth’s viscous mantle, and heat from the planet’s core keeps the mantle from solidifying and locking the continents into place.

The core is hot because of the presence of radioactive elements that came from neutron star collisions. It should be possible to calculate when the first continents formed in the Universe.

So that’s what one researcher did.

September 13, 2023September 13, 2023 by Brian Koberlein

Has the First Biosignature Been Found on an Exoplanet?

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov — Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Recently I wrote about the discovery of a hycean world. A potentially habitable exoplanet with a deep warm ocean and thick, hydrogen-rich atmosphere. Such planets are thought to be somewhat common orbiting red dwarf stars, and they are an excellent candidate for life. While it’s an exciting discovery, buried in the research article was something even more exciting. Tentative evidence of a biosignature, hinting at the presence of life. You can guess which discovery started making headlines. But have astronomers really found life on another planet?

September 1, 2023September 1, 2023 by Evan Gough

Is Anyone Planning for Diplomacy with an Extraterrestrial Civilization?

Artist impression of an alien civilization. Image credit: CfA

Imagine we detect an interstellar object entering our Solar System. At first, astronomers think it’s just another natural interloper like Oumuamua or comet Borisov. We’re warming up to the idea of visitors from other parts of the galaxy, though they’ve been inanimate so far.

But then, what if it becomes clear that something’s different about this visitor? What if it moves unnaturally or somehow behaves purposefully? What if it takes up a stable orbit somewhere? What if, as we gather more evidence, it becomes clear that it’s a probe of some sort sent to us intentionally? What if it communicates with us?

Suddenly, as if thrust into a science fiction plot, humanity is in a totally different situation. What do we do?

June 15, 2023June 15, 2023 by Evan Gough

Did Life Need Plate Tectonics to Emerge?

New research indicates that mobile plate tectonics—thought to be necessary for the creation of a habitable planet—was not occurring on Earth 3.9 billion years ago. Image Credit: University of Rochester illustration / Michael Osadciw

It’s widely accepted that Earth’s plate tectonics are a key factor in life’s emergence. Plate tectonics allows heat to move from the mantle to the crust and plays a critical role in cycling nutrients. They’re also a key part of the carbon cycle that moderates Earth’s temperature.

But new research suggests that there was no plate tectonic activity when life appeared sometime around 3.9 billion years ago. Does this have implications for our search for habitable worlds?

May 30, 2023May 30, 2023 by Evan Gough

A New Place to Search for Habitable Planets: “The Soot Line.”

Artist impression of a young planet-forming disk illustrating the respective locations of the soot and water-ice lines. Planets born interior to the soot line will be silicate-rich. Planets born interior to the water-ice line, but exterior to the soot line will be silicate and soot-rich (“Sooty Worlds”). Planets born exterior to the water-ice line will be water worlds. Image credit: Ari Gea/SayoStudio.

The habitable zone is the region around a star where planets can maintain liquid water on their surface. It’s axiomatic that planets with liquid water are the best places to look for life, and astronomers focus their search on that zone. As far as we can tell, no water equals no life.

But new research suggests another delineation in solar systems that could influence habitability: The Soot Line.

May 18, 2023May 12, 2023 by Paul M. Sutter

Fatty Acids Might Exist in Space

A team of physicists have discovered that the environment of a molecular cloud in interstellar space can support the existence of fatty acids, a key component of life on Earth.

May 11, 2023May 11, 2023 by Evan Gough

Advanced Life Should Have Already Peaked Billions of Years Ago

The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester

Did humanity miss the party? Are SETI, the Drake Equation, and the Fermi Paradox all just artifacts of our ignorance about Advanced Life in the Universe? And if we are wrong, how would we know?

A new study focusing on black holes and their powerful effect on star formation suggests that we, as advanced life, might be relics from a bygone age in the Universe.

May 4, 2023May 4, 2023 by Evan Gough

Solar Flares Could Have Helped Life Get Started on Earth

Solar flares pose a major hazard to electronics and infrastructure in Low Earth Orbit, but they may have played a role in kick-starting life on Earth. Credit: NASA/SDO/J. Major

Stars emit powerful flares that can be deadly for any burgeoning life on nearby planets. Images from spacecraft that monitor the Sun show these flares in glorious, horrifying detail. But the flares from the Sun are mere nuisances compared to some stars. Some stars produce catastrophic superflares, which can be tens of thousands of times more energetic than the Sun’s. That much energy can sterilize a planet’s surface.

But new research shows that a certain amount of flaring activity on the Sun could’ve been beneficial. It could’ve kick-started life on Earth.

March 22, 2023March 22, 2023 by Carolyn Collins Petersen

Did Supernovae Help Push Life to Become More Diverse?

Distant past supernovae could be linked by cosmic ray particles to climate change on Earth and changes in biodiversity. Courtesy: Henrik Svensmark, DTU Space.

Life on Earth has been around for a long time—at least 3.8 billion years. During that time, it evolved significantly. Why has biodiversity here changed so much? A new study proposes a startling idea. Some major diversity changes are linked to supernovae—the explosions of massive stars. If true, it shows that cosmic processes and astrophysical events can influence the evolution of life on our planet.