Flowing Martian Water was Protected by Sheets of Carbon Dioxide

An artistic interpretation of an ice-covered river sourced from meltwater beneath Mars’ south polar cap. Image Credit: Peter Buhler/PSI.

Mars’ ancient climate is one of our Solar System’s most perplexing mysteries. The planet was once wet and warm; now it’s dry and cold. Whatever befell the planet, it didn’t happen all at once.

New research shows that on ancient cold Mars, sheets of frozen carbon dioxide allowed rivers to flow and a sea the size of the Mediterranean to exist.

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From Frozen to Sweltering: Earth’s Climate Over the Last 485 Million Years

New research shows the global mean surface temperature across the last 485 million years. The gray shading corresponds to different confidence levels, and the black line shows the average. The colored bands along the top reflect the climate state, with cooler colors indicating icehouse (coolhouse and coldhouse) climates, warmer colors indicating greenhouse (warmhouse and hothouse) climates, and the gray representing a transitional state. Image Credit: Judd et al. 2024.

Earth’s last half-billion years were action-packed. During that time, the climate underwent many changes. There have been changes in ocean levels and ice sheets, changes in the atmosphere’s composition, changes in ocean chemistry, and ongoing biological evolution punctuated with extinction events.

A record of Earth’s temperature over the last 485 million years is helping scientists understand how it all played out and illustrating what could happen if we continue to enrich the atmosphere with carbon.

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Life Might Thrive on the Surface of Earth for an Extra Billion Years

This view of Earth from space is a fusion of science and art, drawing on data from multiple satellite missions and the talents of NASA scientists and graphic artists. This image originally appeared in the NASA Earth Observatory story Twin Blue Marbles. Image Credits: NASA images by Reto Stöckli, based on data from NASA and NOAA.

The Sun is midway through its life of fusion. It’s about five billion years old, and though its life is far from over, it will undergo some pronounced changes as it ages. Over the next billion years, the Sun will continue to brighten.

That means things will change here on Earth.

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Our Carbon Dioxide Emissions Have a Mesmerizing Side

This screenshot is from NASA's new global CO2 visualization. Image Credit: NASA/SVS

Our CO2 emissions are warming the planet and making life uncomfortable and even unbearable in some regions. In July, the planet set consecutive records for the hottest day.

NASA is mapping our emissions, and while what they show us isn’t uplifting, it is visually appealing in a ghoulish way. Maybe the combination of visual appeal and ghoulishness will build momentum in the fight against climate change.

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The LIFE Telescope Passed its First Test: It Detected Biosignatures on Earth.

LIFE will have five separate space telescopes that fly in formation and work together to detect biosignatures in exoplanet atmospheres. Image Credit: LIFE, ETH Zurich

We know that there are thousands of exoplanets out there, with many millions more waiting to be discovered. But the vast majority of exoplanets are simply uninhabitable. For the few that may be habitable, we can only determine if they are by examining their atmospheres. LIFE, the Large Interferometer for Exoplanets, can help.

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Another Explanation for K2-18b? A Gas-Rich Mini-Neptune with No Habitable Surface

Artist depiction of the mini-Neptune K2-18 b. Credit: NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)

Exoplanet K2-18b is garnering a lot of attention. James Webb Space Telescope spectroscopy shows it has carbon and methane in its atmosphere. Those results, along with other observations, suggest the planet could be a long-hypothesized ‘Hycean World.’ But new research counters that.

Instead, the planet could be a gaseous mini-Neptune.

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JWST Takes a Detailed Look at Jupiter’s Moon Ganymede

Juno captured this image of Ganymede in July 2022. Now the JWST is taking a look at our Solar System's largest moon. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

Nature doesn’t conform to our ideas of neatly-contained categories. Many things in nature blur the lines we try to draw around them. That’s true of Jupiter’s moon Ganymede, the largest moon in the Solar System.

The JWST took a closer look at Ganymede, the moon that’s kind of like a planet, to understand its surface better.

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The JWST Just Found Carbon on Europa, Boosting the Moon’s Potential Habitability

This reprocessed colour view of Jupiter’s moon Europa was made from images taken by NASA's Galileo spacecraft in the late 1990s. Credit: NASA/JPL-Caltech

Most planets and moons in the Solar System are clearly dead and totally unsuitable for life. Earth is the only exception. But there are a few worlds where there are intriguing possibilities of life.

Chief among them is Jupiter’s moon Europa, and the JWST just discovered carbon there. That makes the moon and its subsurface ocean an even more desirable target in the search for life.

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Geoengineering is Shockingly Inexpensive

Geoengineering isn't a quick fix for our climate crisis, and it's also expensive. Image Credit: University of Leeds

Despite decades of warnings and international climate agreements, global carbon emissions are still rising. Carbon emissions seem like an unstoppable juggernaut as energy-hungry humans keep breeding and pursuing more affluent lifestyles. Reducing emissions won’t be enough to confront the climate crisis; we need additional solutions.

Geoengineering, also called climate engineering, could be the solution we seek. But is it financially feasible?

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JWST Finds a Comet Still Holding Onto Water in the Main Asteroid Belt

This artist's illustration shows the rocky body of a comet with a detailed, cratered surface. Glowing rays emanate from the rocky surface like sunlight through clouds, representing water ice being vapourised by the heat of the Sun. Image Credit: NASA, ESA

Comets are instantly recognizable by their tails of gas and dust. Most comets originate in the far, frozen reaches of our Solar System, and only visit the inner Solar System occasionally. But some are in the Main Asteroid Belt, mixed in with the debris left over after the Solar System formed.

Astronomers just found water vapour coming from one of them.

“With Webb’s observations of Comet Read, we can now demonstrate that water ice from the early Solar System can be preserved in the asteroid belt.”

Michael Kelley, University of Maryland
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