Remember When Life was Found in a Martian Meteorite? Turns out, it was Just Geology

The Alan Hills meteorite is a part of history to Mars aficionados. It came from Mars and meteorite hunters discovered in Antarctica in 1984. Scientists think it’s one of the oldest chunks of rock to come from Mars and make it to Earth.

The meteorite made headlines in 1996 when a team of researchers said they found evidence of life in it.

Did they?

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Is That a Fossil on Mars? Non-Biological Deposits can Mimic Organic Structures

There’s nothing easy about searching for evidence of life on Mars. Not only do we somehow have to land a rover there, which is extraordinarily difficult. But the rover needs the right instruments, and it has to search in the right location. Right now, the Perseverance lander has checked those boxes as it pursues its mission in Jezero Crater.

But there’s another problem: there are structures that look like fossils but aren’t. Many natural chemical processes produce structures that mimic biological ones. How can we tell them apart? How can we prepare for these false positives?

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Greenland’s Ice Sheet is Similar in Many Ways to the Solar System’s Icy Worlds and Can Teach Us How to Search for Life

Many regions on Earth are temperate, nutrient-rich, stable environments where life seems to thrive effortlessly. But not all of Earth. Some parts, like Greenland’s ice sheet, are inhospitable.

In our nascent search for life elsewhere in the Solar System, it stands to reason that we’ll be looking at worlds that are marginal and inhospitable. Icy worlds like Jupiter’s moon Europa and Saturn’s moon Enceladus are our most likely targets. These frozen worlds have warm oceans under layers of ice.

What can Greenland’s cryo-ecosystems tell us about searching for life on icy bodies like Europa and Enceladus?

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The Interior of Enceladus Looks Really Great for Supporting Life

When NASA’s Voyager spacecraft visited Saturn’s moon Enceladus, they found a body with young, reflective, icy surface features. Some parts of the surface were older and marked with craters, but the rest had clearly been resurfaced. It was clear evidence that Enceladus was geologically active. The moon is also close to Saturn’s E-ring, and scientists think Enceladus might be the source of the material in that ring, further indicating geological activity.

Since then, we’ve learned a lot more about the frigid moon. It almost certainly has a warm and salty subsurface ocean below its icy exterior, making it a prime target in the search for life. The Cassini spacecraft detected molecular hydrogen—a potential food source for microbes—in plumes coming from Enceladus’ subsurface ocean, and that energized the conversation around the moon’s potential to host life.

Now a new paper uses modelling to understand Enceladus’ chemistry better. The team of researchers behind it says that the subsurface ocean may contain a variety of chemicals that could support a diverse community of microbes.

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This is What Perseverance’s Landing Site Looked Like Billions of Years Ago. See Why it’s Such a Compelling Target?

Today is a milestone in NASA’s Perseverance mission to Mars. At 1:40 pm Pacific time today, the rover will have traveled 235.4 million km (146.3 million miles). That means the spacecraft is halfway to Mars and its rendezvous with Jezero Crater. The spacecraft isn’t traveling in a straight line, and the planets are moving, so it’s not equidistant to both planets.

“Although we’re halfway into the distance we need to travel to Mars, the rover is not halfway between the two worlds,” Kangas explained. “In straight-line distance, Earth is 26.6 million miles [42.7 million kilometers] behind Perseverance and Mars is 17.9 million miles [28.8 million kilometers] in front.”

But today’s still a good time to take another look at Jezero Crater, and why NASA chose it as the mission’s target.

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Here’s a Clever Idea, Looking for the Shadows of Trees On Exoplanets to Detect Multicellular Life

That’s the kind of headline that can leave us scratching our heads. How can you see tree shadows on other worlds, when those planets are tens or hundreds of light years—or even further—away. As it turns out, there might be a way to do it.

One team of researchers thinks that the idea could potentially be used to answer one of humanity’s long-standing questions: Are we alone?

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Maybe Volcanoes Could Explain the Phosphine in Venus’ Atmosphere

The detection of phosphine in Venus’ atmosphere was one of those quintessential moments in space science. It was an unexpected discovery, and when combined with our incomplete understanding of planetary science, and our wistful hopefulness around the discovery of life, the result was a potent mix that lit up internet headlines.

As always, some of the headlines were a bit of an over-reach. But that’s the way it goes.

At the heart of it all, there is compelling science. And the same, overarching question that keeps popping up: Are we alone?

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Why Lava Tubes Should be Our Top Exploration Priority on Other Worlds

When magma comes out of the Earth onto the surface, it flows as lava. Those lava flows are fascinating to watch, and they leave behind some unique landforms and rocks. But a lot of what’s fascinating about these flows can be hidden underground, as lava tubes.

These lava tubes are turning out to be a very desirable target for exploration on other worlds, just as they are here on Earth.

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