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Nature could be said to be constructed out an immense number of physical processes… indeed, that’s almost the definition of “physics”. But what makes a physical process a measurement? And once we understand that, what makes a measurement in quantum physics, a fraught topic, different from measurements that we typically perform as teenagers in a grade school science class?

We could have a long debate about this. But for now I prefer to just give examples that illustrate some key features of measurements, and to focus attention on perhaps the simplest intuitive measurement device… one that we’ll explore further and put to use in many interesting examples of quantum physics.

Measurements and Devices

We typically think of measurements as something that humans do. But not all measurements are human artifice. A small fraction of physical processes are natural measurements, occuring without human intervention. What distinguishes a measurement from some other garden variety process?

A central element of a measurement is a device, natural or artificial, simple or complicated, that records some aspect of a physical process semi-permanently, so that this record can be read out after the process is over, at least for a little while.

For example, the Earth itself can serve as a measurement device. Meteor Crater in Arizona, USA is the record of a crude measurement of the size, energy and speed of a large rock, as well of how long ago it impacted Earth’s surface. No human set out to make the measurement, but the crater’s details are just as revealing as any human experiment. It’s true that to appreciate and understand this measurement fully requires work by humans: theoretical calculations and additional measurements. But still, it’s the Earth that recorded the event and stored the data, as any measurement device should.

Figure 1: A rock’s energy, measured by the Earth. Meteor Crater, Arizona, USA; National Map Seamless Server – NASA Earth Observatory

The Earth has served as a measurement device in many other ways: its fossils have recorded its life forms, its sedimentary rocks have recorded the presence of its ancient seas, and a layer of iridium and shocked quartz have provided a record of the giant meteor that killed off the dinosaurs (excepting birds) along with many other species. The data from those measurements sat for many millions of years, unknown until human scientists began reading it out.

I’m being superficial here, skipping over all sorts of subtle issues. For instance, when does a measurement start, and when is it over? For instance, did the measurement of the rock that formed Meteor Crater start when the Earth and the future meteor were first created in the early days of the solar system, or only when the rock was within striking distance of our planet? Was it over when Meteor Crater had solidified, or was it complete when the first human measured its size and shape, or was it finished when humans first inferred the size of the rock that made the crater? I don’t want to dwell on these definitional questions today. The point I’m making here is that measurement has nothing intrinsically to do with human beings per se. It has to do with the ability to record a process in such a way that facts about that process can be extracted, long after the process is over.

The measurement device for any particular process has to satisfy some basic requirements.

• Pre-measurement metastability: The device must be fairly stable before the process occurs, so that it doesn’t react or change prematurely, but not so stable that it can’t change when the process takes place.
• Sensitivity: During the interaction between the device and whatever is being measured, the device needs to react or change in some substantial way that is predictable (at least in part).
• Post-measurement stability: The change to the device during the measurement has to be semi-permanent, long-lasting enough that there’s time to detect and interpret it.
• Interpretability: The change to the device has to be substantial and unambiguous enough that it can be used to extract information about what was measured.

Examples of Devices

A simple example: consider a small paper cup as a device for measuring the possible passage of a rubber ball. If the paper cup is sitting on a flat, horizontal table, it is reasonably stable and won’t go anywhere, barring a strong gust of wind. But if a rubber ball goes flying by and hits the cup, the cup will be knocked off the table… and thus the cup is very sensitive to the collision with the ball. The change is also stable and semi-permanent; once the cup is on the floor, it won’t spontaneously jump back up onto the table. And so, after setting a cup on a table in a windowless room near a squash court and returning days later, we can figure out from the position of the cup whether a rubber ball (or something similar) has passed close to the cup while we were away. Of course, this is a very crude measurement, but it captures the main idea.

Incidentally, such a measurement is sometimes referred to as “non-destructive”: the cup is so flimsy that its the effect of the cup on the ball is very limited, and so the ball continues onward almost unaffected. This is in contrast to the measurement of the rock that made Meteor Crater, which most certainly was “destructive” to the rock.

Yet even in this destructive event, all the criteria for a measurement are met. The Earth and its dry surface in Arizona are (and were) pretty stable over millennia, despite erosion. The Earth’s surface is very sensitive to a projectile fifty meters across and moving at ten or more kilometers per second; and the resulting deep, slowly-eroding crater represents a substantial, semi-permanent change that we can interpret roughly 50,000 years later.

In Figure 2 is a very simple and crude device designed to measure disturbances ranging from earthquakes to collisions. It consists of a ball sitting stationary within a dimple (a low spot) on a hill. It will remain there as long as it isn’t jostled — it is reasonably stable. But it is sensitive: if an earthquake occurs, or if something comes flying through the air and strikes the ball, it will pop out of the dimple. Then it will roll down the hill, never to return to the its original perch — thus leaving a long-lasting record of the process that disturbed it. We can later read the ball’s absence from the dimple, or its presence far off to the right, as evidence of some kind of violent disturbance, whereas if it remains in the dimple we may conclude that no such violent disturbance has occurred.

Figure 2: If the ball in the dip is subjected to a disturbance, it will end up rolling off to the right, thus recording the existence of the event that disturbed it.

What about measurement devices in quantum physics? The needs are often the same; a measurement still requires a stable yet sensitive device that can respond to an interaction in a substantial, semi-permanent, interpretable way.

Today we’ll keep things very simple, and limit ourselves to a quantum version of Fig. 2, employed in the simplest of circumstances. But soon we’ll see that when measurements involve quantum physics, surprising and unfamiliar issues quickly arise.

An Simple Device for Quantum Measurement

Here’s an example of a suitable device, a sort of microscopic version of Fig. 2. Imagine a small ball of material, perhaps a few atoms wide, that is gently trapped in place by forces that are strong but not too strong. (These might be of the form of an ion trap or an atom trap; or we might even be speaking of a single atom incorporated into a much larger molecule. The details do not matter here.) This being quantum physics, the trap might not hold the ball in place forever, thanks to the process known as “tunneling“; but it can be arranged to stay in place long enough for our purposes.

Figure 3: A nearly-atomic-sized object in an idealized trap; if jostled sharply, it may move past the dark ring and permanently escape.

If the ball is bumped by an atom or subatomic particle flying by at high speed, it may be knocked out of its trap, following which it will keep moving. So if we look in the trap and discover it empty, or if we find the ball far outside the trap, we will know that some energetic object must have passed through the trap. The ball’s location and motion record the existence of that passing object. (They also potentially record additional information, depending on how we set up the experiment, about the object’s motion-energy and its time of arrival.)

To appreciate a measurement involving quantum physics, it’s often best to first think through what happens in a pre-quantum version of the same scenario. Doing so gives us an opportunity to use two complementary views of the measurement: an intuitive one in physical space and more abstract one in the space of possibilities. This will help us interpret the quantum case, where an understanding of a measurement can only be achieved in the space of possibilities.

A Measurement in Pre-Quantum Physics

We’re going to imagine that an incoming projectile (which I’ll draw in purple) is moving along a straight line (which we’ll call the x-axis) and strikes the measuring device — the ball (which I’ll draw in blue) sitting inside its trap. To keep things simple enough to draw, I’ll assume that any collision that occurs will leave the ball and projectile still moving along the x-axis.

With these two objects restricted to a one-dimensional line, our space of possibilities will be two-dimensional, one dimension representing the possible positions x1 of the projectile, and the other representing the possible positions x2 of the ball. (If you are not at all familiar with the space of possibilities and how to think about it, I recommend you first read this article, which addresses the key ideas, and this article, which gives an example very much relevant to this post.)

Below in Fig. 4 is an animation showing what happens, from two viewpoints, as the projectile strikes the ball, allowing the ball’s motion to measure the passage of the projectile.

The first (at left) is the familiar viewpoint: what would happen before our eyes, in physical space, if these objects were big enough to see. The projectile moves to the right, with the ball stationary; a collision occurs, following which the projectile continues on the right, albeit a bit more slowly, and the ball, having popped out of its trap, moves off the the right.

The second viewpoint (at right) is not something we could see; it happens in the space of possibilities (or “configuration space,”) which we can see only in our minds. In this two-dimensional space, with axes that are the projectile’s and ball’s possible positions x1 and x2, the system — the combination of the projectile and ball — is at any moment sitting at one point. That point is indicated by a star; its location has as its x1 coordinate the projectile’s position at a moment in time, while its x2 coordinate is the ball’s position at that same moment in time.

Figure 4: (Left) In physical space, the projectile travels to the right and strikes the stationary ball, causing the latter to move. (Right) The same process seen in the space of possibilities; note the labels on the axes. On the diagonal line, the two objects would be coincident in physical space, with x1 = x2.

The two animations are synchronized in time. I suggest you spend some time with the animation until it is clear to you what is happening.

• Initially, the star moves horizontally. This indicates that the value of x2 isn’t changing; the ball is stationary. Both x1 and x2 are initially negative, so the star is in the lower-left quadrant.
• Notice the diagonal line, at x1 = x2 ; if the system is on that line, a collision between the two objects is occurring, since they are at the same point. It is when the star reaches this line that the ball begins to move, and the star’s motion is correspondingly no longer horizontal.
• After the collision, both the projectile and ball move to the right, which means the values of x1 and x2 are both increasing. This in turn means that the star moves up and to the right following the collision, eventually reaching the upper-right quadrant where both x1 and x2 are positive.

By contrast, if the measurement device were switched off, so that the projectile and the ball could no longer interact, the projectile would just continue its constant motion to the right, unchanged, and the ball would remain at its initial location, as in Fig. 5. In the space of possibilities, the star would move to the right as the projectile’s position x1 steadily increases, while it would remain at the same vertical level because the ball’s position x2 is never changing.

Figure 5: Same as Fig. 4 except that no collision occurs; the ball remains stationary and the projectile continues on steadily. The Same Measurement in Quantum Physics

Now, how do we describe the measurement in quantum physics? In general we cannot portray what happens in a quantum system using only physical space. Instead, our system of two objects is described by a single wave function, which is a function of the space of possibilities. That is, it is a function of x1 and x2, and also time, since it changes from moment to moment. [Important: the system is not described by two wave functions (i.e., one per object), and the single wave function of the system is not a function of physical space, with its coordinate x. There is one wave function, and it is a function of all possibilities.]

At each moment in time, and for each possible arrangement of the system — for each of the possible locations of the two objects, with the projectile having position x1 and the ball having position x2 — this function gives us a complex number Ψ(x1, x2; t). The absolute value squared of this number gives us the probability of the corresponding possibility — the probability that if we choose to measure the positions of the projectile and ball, we will find the projectile has position x1 and that the ball has position x2.

What I’m going to do now is plot for you this wave function, using a 3d plot, where two of the axes are x1 and x2 and the third axis is the absolute value of Ψ(x1, x2; t). [Not its square, though the difference doesn’t matter much here.] The colors give the argument (or “phase”) of the complex number Ψ(x1, x2; t). As suggested by recent plots where we looked at wave functions for a single particle, the flow of the color bands often conveys the motion of the system across the space of possibilities; you’ll see this in the patterns below.

Going in the reverse order from above, let’s first look at the quantum wave function corresponding to Fig. 5, when no measurement takes place and the projectile passes by the ball unimpeded. You can see that the peak in the wave function, telling us most probable values for the results of measurements of x1 and x2, if carried out at a specific time t, moves along roughly the same path as the star in Fig. 5: the most probable values of x1 increase steadily with time, while those of x2 remain fixed.

Figure 6: The wave function corresponding to a quantum version of Fig. 5, with no measurement carried out; the system is most likely to be to be found where the wave function is largest. The projectile’s most likely position x1 steadily increases while the most likely position x2 of the ball remains constant. Compare to the right-hand panel of Fig. 5.

In this situation, the ball’s behavior has nothing to do with the projectile. We cannot learn anything one way or the other about the projectile from the position or motion of the ball.

What about when a measurement takes place, as in Fig. 4? Again, as seen in Fig. 7, the majority of the wave function follows the path of the star, with the most probable values of x2 beginning to increase around the most likely time of the collision. This change in the most likely value of x2 is an indication of the presence of the projectile and its interaction with the ball. [Note: Fig. 7, unlike other quantum wave functions shown in this series, is a sketch, not a precise solution to the full quantum equations; I simply haven’t yet found a set-up where the equations can be solved numerically with enough precision and speed to get a nice-looking result. I expect I’ll eventually find an example, but it might take some time.]

Figure 7: As in Fig. 6, but including the measurement illustrated in Fig. 4. [Note this is only a sketch, not a full calculation.] The most likely position x2 of the ball is initially constant but begins to increase following the collision, thus recording the observation of the projectile. Compare to the right-hand panel of Fig. 4.

More precisely, because of the collision, the motion of the ball is now correlated with that of the projectile — their motions are logically and physically related. That by itself is not unusual; all interactions between objects lead to some level of correlation between them. But this correlation is stable; as a result of the collision, the ball is highly unlikely to be found back in its initial position. And so, when we later look at the trap and find it empty, this does indeed give us reliable information about the projectile, namely that at some point it passed through the trap. (This type of correlation, both within and beyond the measurement context, will be a major topic in the future.)

So far, this all looks quite straightforward. The motion of the star in Fig. 4 is seen in the motion of the peak of the wave function in Fig. 7. Similar behavior is seen in Figs. 5 and 6. But these are simple cases: where the projectile’s motion is well-known, its location is not too uncertain, and the measurement device is almost perfect. We will soon explore far more complex and interesting quantum examples, using this simple one as our conceptual foundation, and things won’t be so straightforward anymore.

I’ll stop here for today. Please let me know in the comments if there are aspects of this story that you find confusing; we need all to be on the same page before we advance into the more subtle elements of our quantum world.

Small nuclear reactors have been around since the 1950s. They mostly have been used in military ships, like aircraft carriers and submarines. They have the specific advantage that such ships could remain at sea for long periods of time without needing to refuel. But small modular reactors have never taken off as a source of grid energy. The prevailing opinion for why this is seems to be that they are simply not cost effective. Larger reactors,  which are already expensive endeavors, produce more megawatts per dollar. SMRs are simply too cost inefficient.

This is unfortunate because they have a lot of advantages. Their initial investment is smaller, even though the cost per unit energy is more. They are safe and reliable. They have a small footprint. And they are scalable. The military uses them because the strategic advantages are worth the higher cost. Some argue that the zero carbon on demand energy they provide is worth the higher cost, and I think this is a solid argument. Also there are continued attempts to develop the technology to bring down the cost. Arguably it may be worth subsidizing the SMR industry so that the technology can be developed to greater cost effectiveness. Decarbonizing the energy sector is worth the investment.

But there is another question – are there civilian applications that would also justify the higher cost per unit energy? I have recently encountered two that are interesting. The first is a direct extension of the military use – using an SMR to power a cargo ship. South Korean company, HD Korea Shipbuilding & Offshore Engineering, has revealed their designs for an SMR powered cargo ship, and has received “approval in principle”. Obviously this is just the beginning phase – they need to actually develop the design and get full approval. But the concept is compelling.

The SMR has a smaller footprint overall than a traditional combustion engine. They do not need space for an exhaust system or for fuel tanks. This saved space can be used for extra cargo – and that extra cargo offsets the higher cost of the SMR. The calculus here is different – you don’t have to compare an SMR to every other form of grid power, including gigawatt scale nuclear. You only have to compare it to other forms of cargo ship propulsion. You have to look at the overall cost effectiveness of the cargo delivery system, not just the production of watts. As an aside, the company is also planning on incorporating a “supercritical carbon dioxide-based propulsion system”, which is about 5% more efficient than traditional steam-based propulsion system.

Shipping accounts for about 3% of global greenhouse gas emissions.  Decarbonizing this sector therefore will be critical for getting close to net zero.

The second potential civilian application is for powering datacenters. Swiss company, Deep Atomic, is developing an SMR that is purpose-built for large data centers, again by leveraging advantages specific to one application. Their design provides not only 60 MWe of power, but 60 MW worth of cooling. Apparently is can use its waste heat to power cooling systems for a data center. The SMR design is also meant to be located right next to the data center, even close to urban centers. The company also hopes to produce these SMR in a factory to help bring down construction costs.

Right now this is just a design, and not a reality, but it’s the idea that’s interesting. Instead of thinking of SMRs as just another method of providing power to the grid, they are being reimagined as being optimized for a specific purpose, which could possibly allow them to gain that extra efficiency to make them cost effective. Data centers, which are increasingly critical to our digital world, are very energy hungry. You can no longer just plug them into the existing grid and expect to get all the energy you need. Right now there is no regulatory requirement for data centers to provide their own energy. In late 2024, Energy Secretary Jennifer Granholm “urged” AI companies to provide their own green energy to power their data centers. Many have responded with plans to do that. But it would not be unreasonable to require them to do so.

Without a plan to power data centers their growing energy demand is not sustainable. This could also completely wipe out any progress we make at trying to decarbonize energy production, as new demand will equal or outstrip any green energy production. This is what has been happening so far. This is another reason why we absolutely need nuclear power if we are going to meet our carbon goals.

There is also the hope that these niche applications of SMRs will bootstrap the entire industry. Making SMRs for ships and data centers could create an economy of scale that brings down the cost of SMRs overall, making them viable for more and more applications.

The post Are Small Modular Reactors Finally Coming? first appeared on NeuroLogica Blog.

For a few evenings around 28 February, every planet in the solar system will be visible in the night sky, thanks to a rare great planetary alignment. Here's how to make sure you don't miss this planetary parade.

While experimenting with waves, researchers discovered that vibrating a container of liquid would cause bubble to "gallop" across its surface

The latest chemicals used in refrigerants and aerosols can break down into pollutants, scientists say.

A research team has successfully developed a super-photostable organic dye after two years of dedicated research demonstrating perseverance akin to that of Marie Curie, who painstakingly extracted just 0.1 grams of radium from eight tons of ore to earn her Nobel Prize.

An engineering student refined a century-old math problem into a simpler, more elegant form, making it easier to use and explore. Divya Tyagi's work expands research in aerodynamics, unlocking new possibilities in wind turbine design that Hermann Glauert, a British aerodynamicist and the original author, did not consider.

An engineering student refined a century-old math problem into a simpler, more elegant form, making it easier to use and explore. Divya Tyagi's work expands research in aerodynamics, unlocking new possibilities in wind turbine design that Hermann Glauert, a British aerodynamicist and the original author, did not consider.

Scientists have harnessed a unique property called incipient ferroelectricity to create a new type of computer memory that could revolutionize how electronic devices work, such as using much less energy and operating in extreme environments like outer space.

Scientists have harnessed a unique property called incipient ferroelectricity to create a new type of computer memory that could revolutionize how electronic devices work, such as using much less energy and operating in extreme environments like outer space.

A planet’s history is told in its ancient rock. Earth’s oldest rocks are in the Canadian Shield, Australia’s Jack Hill, the Greenstone Belts in Greenland, and a handful of other locations. These rocks hold powerful clues to our planet’s history. On Mars, the same holds true.

That’s why NASA’s Perseverance rover is revisiting some of them.

Perseverance is exploring Jezero Crater, an ancient paleolake. Its thick layer of sediments may contain evidence of ancient life on Mars. Every crater has a rim, and Perseverance’s current campaign involves studying the rim. The crater rim is different than the sediments. It’s made of ancient rock uplifted and exposed on the surface by the ancient impact that created Jezero.

On Earth, geologists regularly study rock that has made itself easy to examine by coming up from the deeper crust and presenting itself. The same thing happens on Mars, though impacts do the lifting, not plate tectonics. Perseverance is studying the rocks on the crater rim in its current Crater Rim Campaign. The location it’s exploring is an exposed outcrop named Tablelands.

This image shows Perseverance’s landing ellipse (green circle) and the different regions in the Jezero Crater. The rover is currently exploring the crater rim, shown in purple. Image Credit: NASA/JPL-Caltech/USGS/University of Arizona

One type of rock that can teach us a lot about Mars’ ancient history is serpentine. It’s common on Earth and Mars and forms in the presence of water. Its presence on Mars is some of our strongest evidence that the planet was once wet.

Perseverance sampled Silver Mountain, a rock in the Tablelands. The rover used its abrasion tool on its robotic arm to create a fresh surface it could analyze. That analysis showed Silver Mountain is rich in pyroxene, a type of silicate found in almost every igneous and metamorphic rock. The rover also collected a core.

After that, it visited a rock named Serpentine Lake that showed telltale signs of serpentine. Perseverance used its abrasion tool to clean the rock for a detailed investigation. Serpentine Lake has an intriguing texture, described in a press release as “cookies and cream.” It’s also high in serpentine and other minerals that form in the presence of water.

Perseverance used its Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to examine the Serpentine Lake rock. The rock shows a high concentration of serpentine, indicating that it was exposed to water for a long time, a hint of Mars’ potential ancient habitability. Its unusual texture also hints at complex geological processes. Image Credit: NASA/JPL-Caltech

After that, Perseverance doubled back to revisit a rock named “Cat Arm Reservoir.”

It was the first rock the rover studied on the canyon rim. The rover analyzed its composition and detected coarse pyroxene and feldspar crystals, indicating an igneous origin. Unfortunately, Perseverance’s sample tube was empty. Sometimes, the rock the rover tries to sample is weak and turns to dust. This is rare, but it did happen during the rover’s very first sampling attempt, and it happened again with Cat Arm Reservoir.

This image from NASA’s Perseverance Location Tracker shows the rover’s convoluted path as it explores the rim of Jezero Crater. Image Credit: NASA/JPL

Perseverance travelled a small distance and tried to collect a core sample from Cat Arm Reservoir again. That attempt also failed. Then the rover chose a different spot nearby named “Green Gardens” and successfully collected a core sample. It’s next to the abrasion patch on Serpentine Lake.

NASA’s Mars Perseverance rover acquired this image of the area in front of it. It shows the Serpentine Lake abrasion patch on the right-hand side of the rock, with the Green Gardens sampling location on the left. The rover used its onboard Front Right Hazard Avoidance Camera A and captured the image on Feb. 16, 2025 (sol 1420, or Martian day 1,420 of the Mars 2020 mission) at the local mean solar time of 16:45:19. Image Credit: NASA/JPL-Caltech

Like the Serpentine Lake rock, Green Garden is also green, which is a characteristic of the mineral serpentine. Serpentine forms in the presence of water when hydrothermal vents alter ultramafic rocks. Scientists are interested in these minerals because their structure and composition can reveal the history of water on Mars. On Earth, serpentine rock also hosts microbial life, so the same may have been true on Mars. Unfortunately, it’s not clear how much evidence of this life can be preserved.

Perseverance’s “Green Garden” core sample was collected on February 17th. Image Credit: NASA/JPL-Caltech

Perseverance will spend some more time exploring the Tablelands outcrop. It may re-examine the Serpentine Lake abrasion patch and analyze the debris from the Green Gardens drilling and coring. This could take a couple of weeks.

Next on its agenda is “Broom Point,” further down the crater rim. Broom Point contains a spectacular formation of layered rock, which is also intriguing to scientists.

Mars’ ancient history is told in its ancient rocks, but it’s impossible to know in advance which rock holds which clues and how everything will fall into place.

We don’t know what Perseverance will discover about Broom Point. But the rock will tell us something. It always does.

• Press Release: Cookies, Cream, and Crumbling Cores
• Press Release: Gardens on Mars? No, Just Rocks!
• Press Release: Assessing Perseverance’s First Sample Attempt
• NASA: Where is Perseverance?

The post Perseverance Takes A Second Look At Some Ancient Rocks appeared first on Universe Today.

Data from the Chinese rover Zhurong is adding to the pile of evidence for oceans on ancient Mars. For a year, this little craft traveled over nearly two kilometers of the Martian surface and made radar scans of buried natural structures that look like ocean shorelines.

Zhurong’s ground-penetrating radar (GPR) looked under the surface to a depth of 80 meters. There, the radar instrument found thick layers of material similar to beach deposits on Earth. The best way to create such formations is by wave action stirring up and depositing sediments along the shore of an ocean. If these findings stand, they’ll provide a deeper look into Mars’s ancient warm, wet past, and the existence of long-gone seas.

Map of Utopia Planitia showing the landing site of the Zhurong rover and four proposed ancient shorelines. The landing site is about 280 kilometers north of and some 500 meters lower in elevation than the northern hypothesized shorelines. In its traverse, Zhurong traveled south from its landing site, toward the ancient shorelines. Courtesy: Hai Liu, Guangzhou University, China Figuring Out Mars Shorelines

“The southern Utopia Planitia, where Zhurong landed on May 15, 2021, is one of the largest impact basins on Mars and has long been hypothesized to have once contained an ancient ocean,” said Hai Liu, a professor with the School of Civil Engineering and Transportation at Guangzhou University and a core member of the science team for the Tianwen-1 mission, which included China’s first Mars rover, Zhurong. “Studying this area provides a unique opportunity to investigate whether large bodies of water ever existed in Mars’ northern lowlands and to understand the planet’s climate history.”

At first, scientists considered lava flows or dunes to explain the structures Zhurong measured. But, their shapes say otherwise. “The structures don’t look like sand dunes. They don’t look like an impact crater. They don’t look like lava flows. That’s when we started thinking about oceans,” said Michael Manga, a University of California, Berkeley, professor of earth and planetary science. He was part of Hai’s team that recently published a paper about Zhurong’s findings. “The orientation of these features are parallel to what the old shoreline would have been. They have both the right orientation and the right slope to support the idea that there was an ocean for a long period of time to accumulate the sand-like beach.”

Digging into the Past

Aside from their meteorological and geological value, the presence of these shoreline structures also implies that Mars’s ancient oceans were ice-free. “To make ripples by waves, you need to have an ice-free lake. Now we’re saying we have an ice-free ocean. And rather than ripples, we’re seeing beaches,” Manga said. That tells us Mars was a warmer world—at least for a while. Rivers could well have flowed across the surface, contributing rocks and sediments along the shorelines. And, of course, there are structures that imply the presence of oceans. On Earth, oceans provide life habitats and there’s no reason to think that Mars oceans couldn’t have done that, too.

“The presence of these deposits requires that a good swath of the planet, at least, was hydrologically active for a prolonged period in order to provide this growing shoreline with water, sediment, and potentially nutrients,” said co-author Benjamin Cardenas, an assistant professor of geosciences at The Pennsylvania State University (Penn State). “Shorelines are great locations to look for evidence of past life. It’s thought that the earliest life on Earth began at locations like this, near the interface of air and shallow water.”

Shoreline Evidence for Changes on Mars

As far back as Viking, scientists had images showing what looked like irregular shorelines and flow features on the surface. Those features implied bodies of water and flowing rivers. Other missions returned images and data showing ponded areas where smaller bodies of water existed. More recent missions returned images of regions scoured and changed by catastrophic floods. The shoreline features imply that oceans existed.

We know today that Mars’s surface no longer hosts bodies of water. In the past, much of it escaped to space along with Mars’ atmosphere. But some water also went underground and remains there as ice deposits. And, some combined with rocks to form new minerals. Other geological features seem to point to the existence of Martian oceans, like the shorelines Zhurong and Viking measured.

Schematic showing how a series of beach deposits would have formed at the Zhurong landing site in the distant past on Mars (left) and how long-term physical and chemical weathering on the planet altered the properties of the rocks and minerals and buried the deposits. Courtesy: Hai Liu, Guangzhou University, China

However, the irregular shape of those shorelines continued to intrigue planetary scientists. That’s because they didn’t exactly look like shorelines like we see along Earth’s oceans, which are level. In 2007, Manga came up with the idea that the shapes of the shorelines were altered by changes in the planet’s rotation. Why did that happen? Blame it on volcanoes in the Tharsis region. Some 4 billion years ago volcanic activity there built up a huge bulge. That eventually messed with the planet’s rotation. “Because the spin axis of Mars has changed, the shape of Mars has changed. And so what used to be flat is no longer flat,” Manga explained.

If the findings hold up, the buried shorelines tell a compelling story of the last days of oceans on Mars. Based on the team’s paper, that water appears to have lasted tens of millions of years. As it disappeared and the climate dried up, wind-blown regolith covered the shorelines that Zhurong measured.

For now, the Zhurong data provides a look into shoreline deposits that are pristine—but buried under the subsurface. “There has been a lot of shoreline work done,” said Cardenas, “but it’s always a challenge to know how the last 3.5 billion years of erosion on Mars might have altered or completely erased evidence of an ocean. But not with these deposits. This is a very unique dataset.”

For More Information

Ancient Beaches Testify to Long-ago Ocean on Mars
Ancient Ocean Coastal Deposits Imaged on Mars

The post Rover Finds the Shoreline of an Ancient Beach on Mars appeared first on Universe Today.

Researchers have developed a new technique that predicts nuclear properties in record detail. The study revealed how the structure of a nucleus relates to the force that holds it together. This understanding could advance efforts in quantum physics and across a variety of sectors, from to energy production to national security.

Springtails, small bugs often found crawling through leaf litter and garden soil, are expert jumpers. Inspired by these hopping hexapods, roboticists have made a walking, jumping robot that pushes the boundaries of what small robots can do. The research glimpses a future where nimble microrobots can crawl through tiny spaces, skitter across dangerous ground, and sense their environments without human intervention.

Springtails, small bugs often found crawling through leaf litter and garden soil, are expert jumpers. Inspired by these hopping hexapods, roboticists have made a walking, jumping robot that pushes the boundaries of what small robots can do. The research glimpses a future where nimble microrobots can crawl through tiny spaces, skitter across dangerous ground, and sense their environments without human intervention.

A bioinspired robot can change shape to alter its own physical properties in response to its environment, resulting in a robust and efficient autonomous vehicle as well as a fresh approach to robotic locomotion.

A bioinspired robot can change shape to alter its own physical properties in response to its environment, resulting in a robust and efficient autonomous vehicle as well as a fresh approach to robotic locomotion.

Researchers have developed a generative AI tool that mimics scientists to support and speed up the process of scientific discoveries.

A research team demonstrated the 'world's smallest shooting game,' a unique nanoscale game inspired by classic arcade games. This achievement was made possible by real-time control of the force fields between nanoparticles using focused electron beams. This research has practical applications, as the manipulation of nanoscale objects could revolutionize biomedical engineering and nanotechnology.

A research team demonstrated the 'world's smallest shooting game,' a unique nanoscale game inspired by classic arcade games. This achievement was made possible by real-time control of the force fields between nanoparticles using focused electron beams. This research has practical applications, as the manipulation of nanoscale objects could revolutionize biomedical engineering and nanotechnology.