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.

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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. 

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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.

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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)
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?

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This Early Impact Devastated Life then Gave it a Boost

This graphic depicts what happened when the S2 meteorite struck Earth about 3.26 billion years ago. Initially, it was devastating but eventually it lead to mass blooms. Image Credit: Drabon et al. 2024.

Most of us know about the impact that wiped out the dinosaurs about 66 million years ago. It’s a scientific fact that’s entered mainstream knowledge, maybe because so many of us shared a fascination with dinosaurs as children. However, it’s not the only catastrophic impact that shaped life on Earth.

There was an even more ancient one about 3.26 billion years ago, and its repercussions shaped early life in a unique way.

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Another Building Block of Life Can Handle Venus’ Sulphuric Acid

Radar image of Venus created by the Solar System Visualization project and the Magellan science team at the JPL Multimission Image Processing Laboratory. Credit: NASA/JPL.

Venus is often described as a hellscape. The surface temperature breaches the melting point of lead, and though its atmosphere is dominated by carbon dioxide, it contains enough sulfuric acid to satisfy the comparison with Hades.

But conditions throughout Venus’ ample atmosphere aren’t uniform. There are locations where some of life’s building blocks could resist the planet’s inhospitable nature.

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Dark Oxygen Could Change Our Understanding of Habitability

This image shows a bed of manganese nodules offshore of the Cook Islands. Dark oxygen is produced by manganese nodules on the ocean floor. If the same thing happens on the Solar System's ocean moons, it changes our notion of what worlds could be habitable. Image Credit: By USGS, James Hein - https://www.usgs.gov/media/images/cook-islands-manganese-nodules, CC0, https://commons.wikimedia.org/w/index.php?curid=115692552

The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?

What does it mean for our notion of habitability?

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Asking the Big Question: Where Did Life Originate?

Water's Early Journey in a Solar System
Somehow, life originated on Earth. Even without knowing everything about how that happened, can we learn how likely it is to happen elsewhere? Image Credit: NASA/JPL-Caltech

Where on Earth did life originate, and where else could it occur? A comprehensive answer is most likely a long way off. But it might depend on how many suitable sites for abiogenesis there are on different worlds.

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Ancient Rocks in Mars’ Jezero Crater Confirm Habitability

This Mars Reconnaissance Orbiter image shows Jezero Crater, with Perseverance's landing site and the Fan Front feature. Rocks from the Fan Front sampled in 2022 show evidence of water that predates life on Earth. Image Credit: NASA/JPL-Caltech/MSSS/JHU-APL

According to NASA’s Perseverance rover, ancient rocks in Jezero Crater formed in the presence of water. These sedimentary rocks are more than 3.5 billion years old and may predate the appearance of life on Earth. When and if these samples are returned to Earth, scientists hope to determine if they hold evidence of ancient Martian life.

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