Earth’s Long-Term Habitability Relies on Chemical Cycles. How Can We Better Understand Them?

Biogeochemical cycles move matter around Earth between the atmosphere, the oceans, the lithosphere, and living things. Image Credit: By Alexander Davronov - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=106124364

We, and all other complex life, require stability to evolve. Planetary conditions needed to be benign and long-lived for creatures like us and our multicellular brethren to appear and to persist. On Earth, chemical cycling provides much of the needed stability.

Chemical cycling between the land, atmosphere, lifeforms, and oceans is enormously complex and difficult to study. Typically, researchers try to isolate one cycle and study it. However, new research is examining Earth’s chemical cycling more holistically to try to understand how the planet has stayed in the ‘sweet spot’ for so long.

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Can the Gaia Hypothesis Be Tested in the Lab?

A new paper proposes an experimental setup that could test the classic Daisyworld model — a hypothesis of a self-regulating planetary ecosystem — in the lab via two synthetic bacterial strains. Credit: Victor Maull/Image Designer

During the 1970s, inventor/environmentalist James Lovelock and evolutionary biologist Lynn Margulis proposed the Gaia Hypothesis. This theory posits that Earth is a single, self-regulating system where the atmosphere, hydrosphere, all life, and their inorganic surroundings work together to maintain the conditions for life on the planet. This theory was largely inspired by Lovelock’s work with NASA during the 1960s, where the skilled inventor designed instruments for modeling the climate of Mars and other planets in the Solar System.

According to this theory, planets like Earth would slowly grow warmer and their oceans more acidic without a biosphere that regulates temperature and ensures climate stability. While the theory was readily accepted among environmentalists and climatologists, many in the scientific community have remained skeptical since it was proposed. Until now, it has been impossible to test this theory because it involves forces that work on a planetary scale. But in a recent paper, a team of Spanish scientists proposed an experimental system incorporating synthetic biology that could test the theory on a small scale.

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In 250 Million Years, a Single Supercontinent will Form, Wiping Out Nearly all Mammals

Figure 1 from the study displaying the warmest month average temperature (degrees Celsius) for Earth and the hypothesized supercontinent, Pangea Ultima, 250 million years from now, which the researchers hypothesize would make life for most mammals extremely difficult. (Credit: University of Bristol)

A recent study published in Nature Geoscience uses supercomputer climate models to examine how a supercontinent, dubbed Pangea Ultima (also called Pangea Proxima), that will form 250 million years from now will result in extreme temperatures, making this new supercontinent uninhabitable for life, specifically mammals. This study was conducted by an international team of researchers led by the University of Bristol and holds the potential to help scientists better understand how Earth’s climate could change in the distant future from natural processes, as opposed to climate change.

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Could We Find Aliens Terraforming Other Worlds?

Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons

The first early humans to use fire had no inkling of what it would lead to.

Fire was one of our first technologies, and humans have been making changes to their environments since the advent of controlled fire hundreds of thousands of years ago. Fast forward to current times, and our modern technological and global civilization is changing the Earth’s entire biosphere. From carbon emissions that acidify the oceans and weaken the shells of marine life to microplastics that find their way into organisms’ bloodstreams, our technology is intersecting, or combining, with the biosphere.

This has spawned a useful word: biotechnosphere.

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Scientists Have Been Underestimating the Asteroid That Created the Biggest Known Crater on Earth

South Africa's Vredefort Crater is Earth's largest impact crater. New Research clarifies the power of the impact and its catastrophic effects. Image Credit: NASA Earth Observatory image by Lauren Dauphin / University of Rochester illustration by Julia Joshpe

Ancient impacts played a powerful role in Earth’s complex history. On other Solar System bodies like the Moon or Mercury, the impact history is preserved on their surfaces because there’s nothing to erase it. But Earth’s geologic activity has erased the evidence of impact craters over time, with some help from erosion.

Earth’s complex history has elevated its status among its Solar System siblings and created a world that’s rippling with life. Ancient giant impacts have played a role in that history, bringing catastrophe and disruption and irrevocably changing the course of events. Deciphering the role these giant impacts played is difficult since the evidence is missing or severely degraded. So how do scientists approach this problem?

One crater at a time.

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Antarctica Lost an Ice Shelf, but Gained an Island

The eastern coast of Antarctica has lost most of the Glenzer and Conger ice shelves, as seen in these satellite images taken between November 15, 1989 - January 9, 2022. Credit: NASA GSFC/UMBC JCET.

Collapsing ice shelves on the eastern coast of Antarctica has revealed something never seen before: a landform that might be an island. But this is not the first newly revealed island off the Antarctic coast. A series of islands have appeared as the ice shelves along the continent’s coastline has disintegrated over the past few years.

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Because of Extreme Drought, Lake Powell is Barely a Lake Anymore

This Copernicus Sentinel-2 image allows us a wider view of Lake Powell and its dwindling water levels amidst the climate crisis. Contains modified Copernicus Sentinel data (2022), processed by ESA.

The two largest reservoirs in the United States are now at their lowest levels since they were first created. After several decades of drought – with the past two years classified as intense drought in the US Southwest — both Lake Powell and Lake Mead are shrinking. Recent satellite images show just how dramatic the changes have been, due to the ongoing the climate crisis..

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Scientists Simulate the Climate of Arrakis. It Turns Out Dune is a Pretty Realistic Exoplanet

Is the planet Arrakis realistic? Image Credit: By The Central Intelligence Agency - The World Factbook - Algeria, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29196928

Science fiction author Frank Herbert is renowned for the richly-detailed worlds he created. None of his work is more well-known than “Dune,” which took him six years to complete. Like his other work, Dune is full of detail, including the description of planet Dune, or as the Fremen call it, Arrakis.

Dune is an unforgiving desert world that suffers powerful dust storms and has no rainfall. Scientists who specialize in modelling climates set out to see how realistic Dune is compared to exoplanets. Their conclusion?

Frank Herbert did a great job, considering he created Dune in the 1960s.

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Mars Might Have Lost its Water Quickly

This artist's concept depicts the early Martian environment (right) – believed to contain liquid water and a thicker atmosphere – versus the cold, dry environment seen at Mars today (left). Image Credit: NASA's Goddard Space Flight Center

Mars is an arid place, and aside from a tiny amount of water vapour in the atmosphere, all water exists as ice. But it wasn’t always this arid. Evidence of the planet’s past wet chapter dots the surface. Paleolakes like Jezero Crater, soon to be explored by NASA’s Perseverance Rover, provide stark evidence of Mars’ ancient past. But what happened to all that water?

It disappeared into space, of course. But when? And how quickly?

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Scientists in Japan Have Found a Detailed Record of the Earth’s Last Magnetic Reversal, 773,000 Years Ago

Earth Observation has come a long way. But if satellites could orbit closer to Earth, in VLEO, then our observations would be a lot better. Image Credit: NASA Earth Observatory.

Every 200,000 to 300,000 years Earth’s magnetic poles reverse. What was once the north pole becomes the south, and vice versa. It’s a time of invisible upheaval.

The last reversal was unusual because it was so long ago. For some reason, the poles have remained oriented the way they are now for about three-quarters of a million years. A new study has revealed some of the detail of that reversal.

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