Life Archives

January 13, 2025January 13, 2025 by Mark Thompson

Dormancy Could Be One of the Keys to Life on Earth (and Beyond)

It’s easy to forget that, despite life having existed on Earth for billions of years and despite our relatively carefree existence from total destruction, throughout history there have been events that wiped out nearly everything! Fortunately for many life forms, they have the ability to go dormant and enter a state of reversible, reduced metabolic activity. In this state they are protected from decay and can survive long harsh periods where life would otherwise not survive. Is it just possible therefore that dormancy could also allow life to survive on other worlds like Mars or Venus?

January 11, 2025January 11, 2025 by Mark Thompson

Could We Detect Advanced Civilisations by their Industrial Pollution? Probably Not.

The MAIA satellite mission, a partnership between NASA and Italy's Agenzia Spaziale Italiana (ASI), will investigate the effects of particulate matter air pollution on human health. Suicup/Wikimedia Commons, CC BY-SA 3.0

The hunt for aliens goes hand in hand with the hunt for habitable planets. Astronomers are on the hunt for exoplanets with atmospheric chemicals that could be a sign of an advanced civilisation. These chemicals, known as technosignatures are found on Earth and are the result of burning fossil fuels. A team of researchers have been exploring Polycyclic Aromatic Hydrocarbons and whether they could detect them.

January 8, 2025January 8, 2025 by Mark Thompson

Planets Without Plate Tectonics Could Still Be Habitable

It has been thought that the existence of plate tectonics has been a significant factor in the shaping of our planet and the evolution of life. Mars and Venus don’t experience such movements of crustal plates but then the differences between the worlds is evident. The exploration of exoplanets too finds many varied environments. Many of these new alien worlds seem to have significant internal heating and so lack plate movements too. Instead a new study reveals that these ‘Ignan Earths’ are more likely to have heat pipes that channel magma to she surface. The likely result is a surface temperature similar to Earth in its hottest period when liquid water started forming.

January 2, 2025January 2, 2025 by Matt Williams

Is There a Fundamental Logic to Life?

Will it be possible someday for astrobiologists to search for life "as we don't know it"? Credit: NASA/Jenny Mottar

One of the more daunting questions related to astrobiology—the search for life in the cosmos—concerns the nature of life itself. For over a century, biologists have known that life on Earth comes down to the basic building blocks of DNA, RNA, and amino acids. What’s more, studies of the fossil record have shown that life has been subject to many evolutionary pathways leading to diverse organisms. At the same time, there is ample evidence that convergence and constraints play a strong role in limiting the types of evolutionary domains life can achieve.

For astrobiologists, this naturally raises questions about extraterrestrial life, which is currently constrained by our limited frame of reference. For instance, can scientists predict what life may be like on other planets based on what is known about life here on Earth? An international team led by researchers from the Santa Fe Institute (SFI) addressed these and other questions in a recent paper. After considering case studies across various fields, they conclude that certain fundamental limits prevent some life forms from existing.

December 11, 2024December 11, 2024 by Evan Gough

Does Life Really Need Planets? Maybe Not

Newly discovered Earth-size planet TOI 700 e orbits within the habitable zone of its star in this illustration. New research questions whether planets are necessary for life. Image Credit: NASA/JPL-Caltech/Robert Hurt

Do we have a planetary bias when it comes to understanding where life can perpetuate? It’s only natural that we do. After all, we’re on one.

However, planets may not be necessary for life, and a pair of scientists from Scotland and the USA are inviting us to reconsider the notion.

November 27, 2024November 27, 2024 by Brian Koberlein

Asteroid Samples Returned to Earth Were Immediately Colonized by Bacteria

Electron microscope images of sample A0180, showing the presence of life. Credit: Genge, et al

We’ve known for a while that complex chemistry occurs in space. Organic molecules have been detected in cold molecular clouds, and we have even found sugars and amino acids, the so-called “building blocks of life,” within several asteroids. The raw ingredients of terrestrial life are common in the Universe, and meteorites and comets may have even seeded Earth with those ingredients. This idea isn’t controversial. But there is a more radical idea that Earth was seeded not just with the building blocks of life but life itself. It’s known as panspermia, and a recent study has brought the idea back to popular science headlines. But the study is more subtle and interesting than some headlines suggest.

November 14, 2024November 14, 2024 by Evan Gough

A New Way to Detect Daisy Worlds

Daisy Worlds are planets where the biosphere regulates the environment to keep it habitable. Earth is one, sort of. Can we use information theory to identify agnostic biosignatures from these living worlds? Image Credit: NASA

The Daisy World model describes a hypothetical planet that self-regulates, maintaining a delicate balance involving its biogeochemical cycles, climate, and feedback loops that keep it habitable. It’s associated with the Gaia Hypothesis developed by James Lovelock. How can we detect these worlds if they’re out there?

By looking closely at information.

November 13, 2024November 13, 2024 by Mark Thompson

How Life Could Live Under the Ice on Mars

Water ice in a Martian gully. This image, showing part of a region called Dao Vallis, was captured by NASA’s Mars Reconnaissance Orbiter in 2009. Credit: NASA/JPL-Caltech/University of Arizona

Mars has been a fascination to us for centuries. Early observations falsely gave impressions of an intelligent civilisation but early visiting probes revealed a stark, desolate world. Underneath the surface is a few metres of water ice and a recent study by NASA suggests sunlight could reach the layer. If it does, it may allow photosynthesis in the meltwater. On Earth this actually happened and biologists have found similar pools teeming with life.

October 29, 2024October 29, 2024 by Matt Williams

Astronomers Discover Potential New Building Block of Organic Matter in Interstellar Space

A new study expands on the classical theory of panspermia, addressing whether or not life could be distributed on a galactic scale. Credit: NASA

Carbon is the building block for all life on Earth and accounts for approximately 45–50% of all dry biomass. When bonded with elements like hydrogen, it produces the organic molecules known as hydrocarbons. When bonded with hydrogen, oxygen, nitrogen, and phosphorus, it produces pyrimidines and purines, the very basis for DNA. The carbon cycle, where carbon atoms continually travel from the atmosphere to the Earth and back again, is also integral to maintaining life on Earth over time.

As a result, scientists believe that carbon should be easy to find in space, but this is not always the case. While it has been observed in many places, astronomers have not found it in the volumes they would expect to. However, a new study by an international team of researchers from the Massachusetts Institute of Technology (MIT) and the Harvard-Smithsonian Center for Astrophysics (CfA) has revealed a new type of complex molecule in interstellar space. Known as 1-cyanoprene, this discovery could reveal where the building blocks of life can be found and how they evolve.

October 23, 2024October 23, 2024 by Carolyn Collins Petersen

Life Can Maintain a Habitable Environment in Hostile Conditions

Astronomers have detected thousands of planets, including dozens that are potentially habitable. To winnow them down, they need to understand their atmospheres and other factors. (NASA Illustration)

Everybody knows that for life to thrive on any world, you need water, warmth, and something to eat. It’s like a habitability mantra. But, what other factors affect habitability? What if you relaxed the conditions conducive to life? Would it still exist? If so, what would it be?