Since the 1976 Viking missions, when NASA first successfully placed uncrewed landers on Mars, scientists who study life in the universe, known as astrobiologists, have been gathering evidence to determine whether microorganisms ever lived on the red planet. It has been a challenging determination to make. Until a Mars sample return mission occurs, all necessary analyses must take place on Mars, using instruments designed as much to withstand the stresses of space travel as to collect data, which limits how thoroughly scientists can study Martian rocks. As a result, the search for evidence of microbial life on Mars is inherently incremental. 

Recently, scientists added another piece of exciting, yet inconclusive, evidence to their search. In the summer of 2024, the Mars 2020 Perseverance Rover science team was searching for signs of ancient microbial life in a 3,700-million-year-old lake bed on Mars, known as Jezero Crater. In the process, they detected complex, carbon-containing organic molecules in mudstones within a river channel that once brought water to the now-dry lake bed. 

This is not the first time complex organic molecules have been detected in Martian mudstones. However, there are 2 reasons that astrobiologists are particularly interested in this new discovery. First, these organic molecules are widely dispersed across all 4 river channel mudstones they analyzed. Second, some of the organic molecules they found are associated with minerals that are known to support microbial life on Earth. 

Widely dispersed organic molecules associated with minerals that can support microbial life are exactly what astrobiologists would expect to see if microorganisms once lived in Jezero Crater. However, organic molecules can also form through geological processes, like when gases and minerals react at high temperatures and pressures at deep-sea vents on Earth. Therefore, astrobiologists must carefully assess organic molecules to determine their origin. 

In July of 2026, more than 60 Perseverance science team members took a first step towards determining whether ancient microorganisms could have made the organic molecules found in Jezero Crater. They compared the organic molecule detections in Martian mudstones to similar detections of organic molecules in samples of known origin, including fossilized Earth life, meteorites, and minerals. 

NASA scientists detected the organic molecules in Jezero Crater with a rover instrument called Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC). SHERLOC uses a 248.6 nanometer (nm) wavelength laser to excite molecules in unknown materials. When molecules are excited, they absorb and scatter the laser light, causing characteristic shifts in the wavelength of the scattered light. 

Instruments like this, known as Raman spectrometers, detect the shifted light and display the detections as lines called spectra, which scientists use to identify the unknown molecules. The Raman spectra from the 4 mudstones in Jezero crater showed shifts of about 1600 nm, which is characteristic of complex carbon molecules. These shifts appear as bands in the spectra that are often called G-bands.

Raman spectrometers are common laboratory instruments, but most use lasers with wavelengths of 485 nm or higher, so the spectra they produce can be slightly different from SHERLOC spectra even when the laser excites the same kind of molecule. To get around this issue, the scientists compared the Mars spectra with spectra of complex carbon molecules from fossilized Earth microorganisms, coal, graphite, meteorites, and synthetic samples collected by Raman instruments using the same wavelength laser that SHERLOC uses. They found that the spectra collected on Mars overlap with at least one example from every sample type except graphite. 

These results don’t rule out the possibility that organic molecules in Jezero Crater were produced by ancient microbial life, but they can’t tell us exactly how they formed either. That determination will have to wait until the samples are brought to Earth so they can be studied with laboratory instruments.

The Perseverance team has made a small but critical contribution towards determining whether microbial life ever inhabited our closest planetary neighbor, Mars. Their efforts exemplify how the science of astrobiology and the search for possible extraterrestrial life slowly and carefully move forward. If we keep at it, humans may one day have a definitive answer to one of our most consequential questions: Are we alone?

The post Are Martian organics remnants of ancient life? appeared first on Sciworthy.

Reframing subjective policy issues as questions of objective “science” makes it easier to justify relying on “experts” for policy answers.

Source

The human brain is remarkably adept at juggling different kinds of information, allowing us to switch rapidly between tasks and adapt our behavior as circumstances change. A new study by MIT neuroscientists takes a closer look at how the brain accomplishes this, providing evidence for flexible neural modules that may help support this cognitive versatility.

Using mice, scientists found that a group of neurons in the prefrontal cortex could switch between retaining sensory information and maintaining an action plan in working memory.

“We found that the brain doesn’t dedicate a separate group of neurons for every type of information,” says Yuma Osako, an MIT postdoc and the lead author of the new study. “Instead, it uses the same populations of neurons to perform the same computation on different kinds of information, which means the same subset of neurons can hold both an action and a sensory stimulus in working memory,”

The findings also lend support to a longstanding theory known as compositionality—the idea that cognition can be constructed by combining and reusing neural components.

“One of the solutions that’s always been proposed has been this idea of compositionality — that you can take pieces of cognition that perform part of a task and reuse them in another task,” says Timothy Buschman, a professor at the Princeton Neuroscience Institute, and the senior author of the paper, in a statement. 

Another way to see this is to view it as “cognitive Legos,” Buschman suggests. Instead of building a new neural circuit when a new task starts, the brain reuses existing circuits and combines them in different ways.

The Test 

To see how this neural network operates, the scientists trained mice to compare two tones and respond depending on whether the sounds matched. As the mice performed the tasks, the scientists recorded electrical activity from thousands of neurons. 

“When mice do tasks that test whether memory computations can be reused, the answer is they are,” notes Mriganka Sur, the Newton Professor of Neuroscience at MIT’s Picower Institute for Learning and Memory. “There are subspaces of functional activity in the prefrontal cortex that can be the substrate of mixing and matching toward flexible cognition.”

Two important components of the task allowed the researchers to examine how different kinds of information were maintained. First, the mice had to remember the initial tone for a short period. They then had to retain their decision and form an action plan.

In the parietal cortex, neurons were dedicated to storing information about the tone. However, researchers found something different in the prefrontal cortex: a specific group of neurons could switch roles.

During one stage of the task, the circuit helped maintain a sensory memory. During another, the same population was involved in maintaining an action plan. This flexibility may help explain how a finite number of neurons can support an enormous range of behaviors.

“Our everyday life requires us to temporarily hold many different kinds of information. One big question is how the brain can represent an unlimited variability of information using only a finite number of neurons,” Osako says.

The researchers view these reusable neural circuits as potential building blocks for flexible cognition. More broadly, the findings suggest that the brain may be less like a machine filled with components dedicated to individual tasks and more like an interconnected system that continually repurposes its existing neural resources.

The recent study appeared in the journal Nature.

Chrissy Newton is a PR professional and the founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com. To contact Chrissy with a story, please email chrissy @ thedebrief.org.

A timeline of key scientific discoveries from the 16th to the 21st century highlights the early role of the Christian worldview in the Scientific Revolution. Influential founding figures like Newton, Faraday, and Maxwell linked their faith to their scientific contributions. Yet a decline in Christian influence among later scientists is noted.

In Nolan's supposal, the mad scientist takes on the mystique of a wizard. Perhaps this is fitting, given that he sees science and wizardry as the same thing.

Source