Category: 7. Science

Incorporating small amounts of oxidants into methane pyrolysis can significantly enhance carbon and hydrogen production and sustain catalyst activity. Given oxidants are normally considered contaminants in methane pyrolysis, the work calls into question long-standing beliefs about the process.

Methane pyrolysis uses heat to break methane down in the absence of oxygen, generating hydrogen gas and solid carbon. Adding a catalyst lowers the required temperature and speeds up the reaction. It’s a promising route to low- or zero-emission hydrogen, with the added benefit of fitting into existing infrastructure, making it potentially easy to scale. Plus, the solid carbon byproduct can be put to good use.

Working with a fluidised bed reactor filled with Fe/Al₂O₃ catalyst at 750°C, Marco Gigantino, Henry Moise, and colleagues from Stanford University in the US, demonstrated that introducing just 5% carbon dioxide into the methane stream doubled the carbon yield over an hour of operation, with a corresponding hydrogen boost. This addition produced carbon monoxide as a byproduct. Microscopy showed that carbon dioxide enabled the formation of thick carbon layers prone to detachment via fluidisation, ideal for harvesting solid carbon without deactivating the catalyst.

Adding water and oxygen yielded similar benefits. Optimal oxidant-to-methane ratios were determined for both carbon dioxide and water, each yielding over 30% more carbon than methane alone after 14 minutes. When tested on Ni/Al₂O₃ and Co/Al₂O₃ catalysts, the carbon dioxide co-feed continued to outperform methane-only conditions.

Cementite (Fe₃C) is a key intermediate in the breakdown of methane. Gigantino and co-workers identified that oxidants speed up the breakdown of cementite, boosting carbon production by regenerating active sites on the catalyst surface. This showed that the catalyst phases are in constant flux. However, at high oxidant levels, cementite transitions into iron oxides, which reduces catalyst activity – highlighting the need to carefully balance oxidant levels for efficient methane pyrolysis.

Raman spectroscopy revealed a subtle shift in the carbon structure: oxidants promoted the removal of amorphous carbon, favouring the growth of graphitic materials, including carbon nanotubes. The team observed that this not only improved catalyst longevity but enhanced the quality of the solid carbon byproduct. They tested oxidant-assisted methane pyrolysis in monolithic reactors and observed that the results mirrored those in the fluidised bed: the experiments yielded higher conversion rates and greater carbon accumulation when using oxidant co-feeds.

The team also studied the potential economic impact of including small amounts of oxidants. According to Gigantino, ‘higher profitability comes from needing to recycle less methane, which improves operating costs and overall process viability. Compared to steam methane reforming, this approach is also significantly less energy-intensive. We’re confident the energy penalty for separating small amounts of carbon monoxide is minor compared to the efficiency gains.’

Chester Upham, a clean energy scientist from the University of British Columbia, Canada, describes the study as ‘a nice and interesting addition to the field of pyrolysis, which is rapidly growing in interest as a reaction and way of producing affordable clean hydrogen.’

The evidence comes from the Neumark-Nord 2 site in central Germany, dating back 125,000 years to an interglacial period when temperatures were similar to those of today. The site was situated in a lake landscape. At this location, researchers found that Neanderthals not only broke bones to extract marrow but also crushed large mammal bones into tens of thousands of fragments to render calorie-rich bone grease through heating them in water. This discovery substantially shifts our understanding of Neanderthal food strategies, pushing the timeline for this kind of complex, labour–intensive resource management back in time tens of thousands of years.

The findings, led by archaeologists from MONREPOS (Leibniz Zentrum Archaeology, Germany) and Leiden University (The Netherlands), in cooperation with the State Office for Heritage Management and Archaeology Saxony-Anhalt (Germany), indicate that Neanderthals operated what can be described as a prehistoric “fat factory,” carefully selecting a lakeside location to systematically process bones from at least 172 large mammals, including deer, horses and aurochs. These activities, previously believed to be limited to later human groups, now appear to have been part of Neanderthal behavior as early as 125,000 years ago.

This discovery builds on decades of research at the ca. 30 ha large Neumark-Nord site complex already discovered in the 1980s by Jena archaeologist Dietrich Mania. From 2004 to 2009, the Neumark-Nord 2 site was excavated in year-round campaigns by a team led by MONREPOS and Leiden achaeologists. The excavations included a field school, which trained over 175 international students, including dozens of Leiden participants.  

In 2023, the team published evidence that Neanderthals hunted and butchered straight-tusked elephants—up to 13-ton animals that could provide over 2,000 adult daily food portions. The use of fire to manage landscape vegetation and the diversity of processed species at different locations reveal a level of planning and ecological engagement previously underestimated in Neanderthals.

‘What makes Neumark-Nord so exceptional is the preservation of an entire landscape, not just a single site,’ notes Leiden-based author Prof. Wil Roebroeks. ‘We see Neanderthals hunting and minimally butchering deer in one area, processing elephants intensively in another, and—as this study shows—rendering fat from hundreds of mammal skeletons in a centralized location. There’s even some evidence of plant use, which is rarely preserved. This broad range of behaviors in the same landscape gives us a much richer picture of their culture.’

‘This was intensive, organised, and strategic,’ says Dr. Lutz Kindler, the study’s first author. ‘Neanderthals were clearly managing resources with precision—planning hunts, transporting carcasses, and rendering fat in a task-specific area. They understood both the nutritional value of fat and how to access it efficiently – most likely involving caching carcass parts at places in the landscape for later transport to and use at the grease rendering site’.

‘Indeed, bone grease production requires a certain volume of bones to make this labour-intensive processing worthwhile and hence the more bones assembled, the more profitable it becomes’, adds co-author Prof. Sabine Gaudzinski-Windheuser.

The Neumark-Nord discoveries are continuing to reshape our view of Neanderthal adaptability and survival strategies. They show that Neanderthals could plan ahead, process food efficiently, and make sophisticated use of their environment.

The authors emphasise the sheer quantity of herbivores that Neanderthals must have routinely been “harvesting” in this warm-temperate phase: beyond the remains of minimally 172 large mammals processed at that small site alone within a very short period, hundreds of herbivores, including straight-tusked elephants, were butchered around the Neumark-Nord 1 lake in the early Last Interglacial, within the excavated areas only. Other exposures in the wider area around Neumark-Nord have yielded more coarse-grained evidence of regular exploitation of the same range of prey animals, at sites such as Rabutz, Gröbern and Taubach. The last site contained cut-marked remains of 76 rhinos and 40 straight-tusked elephants. Roebroeks: ‘Safely assuming that with these sites we are only looking at the tip of the proverbial ice-berg of Neanderthal impact on herbivore populations, especially on slowly-reproducing taxa, could have been substantial during the Last Interglacial.’

‘The sheer size and extraordinary preservation of the Neumark-Nord site complex gives us a unique chance to study how Neanderthals impacted their environment, both animal and plant life,’ said Dr. Fulco Scherjon, data manager and computer scientist on the project. ‘That’s incredibly rare for a site this old—and it opens exciting new possibilities for future research.’

Main Image: The Neumark-Nord 2/2B site was excavated through year-round campaigns by a core team from 2004 to 2009, alongside an international field school that included more than 175 students in total. Photo: Wil Roebroeks, Leiden University 

Studying civil engineering in the US’s top universities sets you up for a career of undeniable demand. From smart cities to sustainable transport networks, this is a nation with no shortage of examples to inspire you and no dampening of demand for more architects of progress. Demand for civil engineers here is set to surge by 6% by 2033, with no fewer than 22,900 new opportunities each year.

This is a good opportunity – and a great one for anyone who holds a BEng from any of its top institutions. That degree signals to employers your capacity for problem-solving, innovation, leadership, project management, and entrepreneurship. More so if a long list of practical experience comes with it. The following US universities offer programmes that provide both – a solid reputation among employers and a substantial dose of hands-on learning.

University of Alaska Anchorage

Set in the heart of the state’s largest city and its business, industrial, cultural, and recreational centre, the University of Alaska Anchorage is where roughly 12,000 students from the US and 89 countries are pursuing their dreams. Here, culture, innovation and adventure converge – a powerful combination that’s led scores of students to successful futures.

Such outcomes can be attributed to the college’s small class sizes, state-of-the-art engineering facilities, mentorship programmes, and numerous student activities. It’s the full learning experience.

Of the many programmes offered here, Geomatics is a highlightnot only trains you to acquire, analyse, manage, and present geospatial data related to the Earth and its built environment, but graduates also get to work with technology in both indoor and outdoor settings. The programme is one of the few in the US to offer programmes in all six disciplines of geomatics, including land surveying and mapping, geodesy, hydrography, remote sensing, traditional and digital photogrammetry, Light Detection and Ranging (LiDAR), and geographic information systems (GIS).

Lessons do not just end in the classroom, though. You will get to apply the theories you have learned to the real world, working on capstone projects alongside actual clients. From designing intersections, trail systems, websites, wind turbines, and solar hydroponic systems, to conducting research, opportunities are vast. You can also take your expertise to student clubs and organisations where activities include travelling the country to compete in engineering tournaments and visiting conferences to learn from others and present your own research work.

A programme that does this is Civil Engineering. Here, you will gain hands-on experience through the college’s strong partnerships with local consulting firms, government agencies, and non-profit organisations. This allows you to engage with the professional community of Anchorage and assist them with designing real-world projects that will make a difference not only within the city but the world.

Apply to University of Alaska Anchorage today.

George Washington University

George Washington University is committed to creating an even better world. Since its founding can solve them effectively. This is clear for all to see at its School of Engineering & Applied Science.

At this world-class school in the nation’s capital, you learn about the foundations of science and technology, exercise your leadership skills, and be creative when tackling environmental and societal challenges. Whether you’re aiming for engineering, diving deep into computing, or boosting your tech know-how for roles beyond these two fields, GW Engineering has the undergraduate programme for you.

Take the Bachelor of Science with a Major in Civil Engineering programme, for example. Apart from gaining the knowledge and skills to plan, design, and construct buildings, you will also be working on existing real-world projects, such as the clean-up of a deadzone in the Gulf of Mexico, the design of civil infrastructure systems to withstand natural hazards, crash protection for children in car seats, and more. The programme offers an Environmental Engineering Option too, which tackles the economic, environmental, and social aspects of civil engineering.

Guiding you every step of the way are some of the best minds in the field. Over half of faculty members hold doctoral degrees from the nation’s top engineering and computer science programmes. Peers-wise, expect to be part of one of the nation’s most gender-balanced cohorts. GW Engineering has twice the number of female undergraduates compared to other schools.

University of Nebraska-Lincoln

You have the power to shape your future and impact the world – the University of Nebraska–Lincoln is there to only guide you on your journey to success. Since its etablishment in

Its College of Engineering is one of its kind too. It’s the only engineering college in the state, drawing the brightest students here to fulfill their highest aspirations and ambitions.

Here, you work with professors with national and international calibre. They are leaders in their various engineering fields, operate the latest technologies in quality facilities, and engage with a vast network of successful alumni and friends of the college. Their research reaches across the traditional disciplines to apply foundational knowledge to develop and understand the complex systems ranging from the human body to the built and natural environment.

To join them, the BS in Civil Engineering is a good launchpad. Thanks to an 18:1 student-to-faculty ratio, you’ll never be just another face in class. Professors know you and care about your success. Over at Kiewit Hall, you’ll have a US$115 million student-centric engineering hub filled with state-of-the-art classrooms, teaching labs, Engineering Student Services, design/build spaces for student organisations, and a large outdoor quad/promenade for the university community.

As the college aims to turn students into “complete engineers,” practical experience is crucial. As a student here, you’ll learn by using testing equipment to design and monitor critical infrastructure like water treatment and structural systems. You’ll also explore a wide range of specialised courses, tackling design concepts from your freshman year onwards. That’s part of the “Nebraska difference,” the kind that’s led to 80% of students receiving a job offer before graduation.

*Some of the institutions featured in this article are commercial partners of Study International

Here in the 21st century, we’ve learned so much more about our Universe than we could have imagined even just a single generation ago. Back in 1990, we hadn’t discovered any planets orbiting stars beyond our own Solar System; today, we’re closing in on 6000 confirmed exoplanets. Back then, the only prospects for life beyond Earth were potential microbes on planets or moons in our backyard; now, we know of scores of stars that may host living worlds around them. And a number of missions that didn’t just image the other planets and/or moons from afar, but orbited, probed, or even landed on them to explore them have occurred, teaching us about the complex chemistry and composition of worlds that are wildly different from our own.

Over all the time that’s passed since the Voyager missions, however, there are two major planets in our Solar System that remain unexplored from up close — unvisited — since the late 1980s, when Voyager 2 flew by them. Uranus and Neptune, the smallest gas giants in the Solar System and the closest analogues we have to the most common type of exoplanet found thus far: the mini-Neptune. In fact, in recent months, many have speculated that some of these mini-Neptunes may be potentially inhabited, advancing the science case for studying the worlds we do have that are like them, Uranus and Neptune, up close.

Here in the JWST era, we’ve seen these worlds better than ever since Voyager 2’s flyby, but haven’t designed or flown a mission to go visit them in all the time since. 2034 will be the perfect opportunity to change that, however. Here’s the science of why.

Pioneer 11, following in the footsteps of Pioneer 10, actually flew through Jupiter’s lunar system, then used Jupiter’s gravity as an assist maneuver to take it to Saturn. While exploring the Saturnian system, a planetary science first, it discovered and then nearly collided with Saturn’s moon Epimetheus, missing it by an estimated ~4000 km. Newtonian gravity, alone, was capable of calculating these maneuvers.

The Solar System is a complicated — but thankfully, regular — place. The best way to get to the outer Solar System, which is to say, any planet beyond Jupiter, is to use Jupiter itself to help you get there. In physics, whenever you have a small object (like a spacecraft) fly by a massive, stationary one (like a star or planet), the gravitational force can change its velocity tremendously, but its speed must remain the same.

But if there’s a third object that’s gravitationally important, that story changes slightly, and in a way that’s particularly relevant for reaching the outer Solar System. A spacecraft flying by, say, a planet that’s bound to the Sun, can gain-or-lose speed by stealing-or-giving-up momentum to the planet/Sun system. The massive planet doesn’t care, but the spacecraft can get a boost (or a deceleration) depending on its trajectory.

This type of maneuver is known as a gravity assist, and it was essential in getting both Voyager 1 and Voyager 2 on their way out of the Solar System, and more recently, in getting New Horizons to fly by Pluto. Even though Uranus and Neptune have spectacularly long orbital periods of 84 and 165 years, respectively, the mission windows for getting to them recur every 12 years or so: every time Jupiter completes an orbit and lines up with Earth, Uranus, and Neptune once again.

By either passing inside of a planet’s orbit while plunging toward the Sun (as shown), or outside of a planet’s orbit while moving away from the Sun, a spacecraft can get de-boosted via the gravity assist/gravitational slingshot mechanism. The two opposite maneuvers would increase the spacecraft’s speed, resulting in a velocity boost, rather than a de-boost. Both are used in navigating spacecraft across the Solar System.

A spacecraft launched from Earth typically flies by some of the inner planets a few times in preparation for a gravity assist from Jupiter. A spacecraft flying by a planet can get proverbially slingshotted — gravitational slingshot is a word for a gravity assist that boosts it — to greater speeds and energies. If we wanted to, the alignments are right that we could launch a mission to Neptune today. Uranus, being closer, is even easier to get to.

Bac in 2009, the Argo mission was proposed: it would fly-by Jupiter, Saturn, Neptune, and Kuiper belt objects, with a launch window lasting from 2015 to 2019. However, performing flyby missions are relatively easy, because you don’t have to slow the spacecraft down relative to the planet you’re targeting.

Inserting it into orbit around a world is harder, but it’s also far more rewarding. Instead of a single pass, an orbiter can get you whole-world coverage, multiple times, over long periods of time. You can see changes in the atmosphere of a world, and examine it continuously in a wide variety of wavelengths invisible to the human eye. You can find new moons, new rings, and new phenomena that you never expected. You can even send down a lander or probe to the planet or one of its moons. All of that and more already happened around Saturn with the Cassini mission, which came to a planned end in 2017.

A 2012 (top) and a 2016 (bottom) image of Saturn’s north pole, both taken with the Cassini wide-angle camera. The difference in color is due to changes in the chemical composition of Saturn’s atmosphere, as induced by direct photochemical changes.

Cassini didn’t just learn about the physical and atmospheric properties of Saturn, although it did that spectacularly. It didn’t just image and learn about the rings, although it did that too. What’s most incredible is that we observed changes and transient events that we never would have predicted.

• Saturn exhibited seasonal changes, which corresponded to chemical and color changes around its poles.
• A colossal storm developed on Saturn, encircling the planet and lasting for many months.
• Saturn’s rings were found to have intense vertical structures and to change over time; they’re dynamic and not static, and provide a laboratory to teach us about planet-and-moon formation.
• And, with its data, we solved old problems and discovered new mysteries about its moons Iapetus, Titan, and Enceladus, among others.

In other words, we discovered all that we discovered about Saturn — along with its system of moons and rings — because we dared to go there with a high-tech, radiation-hard dedicated orbiter mission, and because we equipped it with a suite of instruments that could probe so much about this planet and the moons it encountered. It was loaded with discovery potential, and that enabled it to find out what was previously unknown about the Saturnian system: to the benefit of all of humanity.

Over a period of 8 months, the largest storm in the Solar System raged, encircling the entire gas giant world. The storm itself was large enough that it was capable of fitting as many as 10-to-12 Earths inside. Cassini, although it wasn’t expecting this to occur, was equipped with instrument technology that was more than sufficient to discover and study this unprecedented feature.

Without a doubt, there’s no question that we absolutely want to do the analogous things for Uranus and Neptune. Many orbiting missions to Uranus and Neptune have been proposed and made it quite far in the mission submission process, but none have actually been slated to be built or fly. NASA, the ESA, JPL, and the UK have all proposed Uranus orbiters that are still in the running, but no one knows what the future holds.

One of the major, flagship-class missions proposed to NASA’s planetary science decadal survey in 2011 was a Uranus probe and orbiter; it was ranked #3, but in the most recent planetary science decadal, it was ranked as the highest-priority planetary flagship mission. Uranus, as well as its outer neighbor, Neptune, are both suspected (based on modeling and Voyager 2 data) to have enormous liquid oceans beneath their atmospheres, which an orbiter should be able to discover for certain. The mission could also include an atmospheric probe, with the potential to measure cloud-forming molecules, heat distribution, and how wind speed changes with depth.

In all the time since Voyager 2, which flew by Uranus in 1986 and Neptune in 1989, we’ve only studied these planets from afar. The most recent views that we have of these worlds, however, are indeed the most spectacular ones obtained in all the time since: visions of Uranus and Neptune from the James Webb Space Telescope.

Numerous features surrounding Neptune, as identified in the JWST images. All 7 of Neptune’s inner moons can be seen here, along with the two main rings and two dusty, more diffuse rings seen here. Triton, although captured by JWST, is too far away to be a part of this cropped JWST image.

JWST’s views of Uranus and Neptune showed us features we only ever had hints of from Voyager 2 data, with Uranus in particular making a very interesting test case. You see, Neptune got its JWST close-up more than halfway through 2022, and so many features were revealed in a visually stunning way. They include:

• Neptune’s disk,
• its highly reflective clouds,
• all seven of its known inner moons,
• its four major rings (Adams, Lassell, Le Verrier, and Galle),
• and its highly reflective largest moon, Triton,

in our best view of all of these features since 1989’s visit.

Uranus, on the other hand, has already been viewed twice by JWST, with its second, superior looking coming in late 2023. Uranus is a bit special: of all the planets in the Solar System, it’s the only one that rotates primarily on its side, with its rotational axis oriented at a nearly 90° tilt (at around 98°) to the “vertical” rotation of the other planets. With an 84 year orbit around the Sun, this means that every 21 years, it undergoes transitions from Uranian solstice, where one pole points directly at the Sun and the other point directly away, to Uranian equinox, where each part of that world receives equal night and daylight, and then back again in the next 21 years.

When Voyager 2 flew by Uranus in 1986, the planet was near solstice, with its southern hemisphere facing the Sun and its northern hemisphere facing away. In 2007, Uranus achieved equinox, and now heads toward its next 2028 solstice. It won’t reach equinox again until 2049, when JWST will likely be out of fuel and defunct, but when an orbiter mission could be present.

When Voyager 2 flew by Uranus in 1986, it was at Uranian solstice. It appeared bland and featureless due to the Sun heating one of its poles, not the entire, rapidly rotating planet. Then, in 2007, Uranus was at equinox, displaying rapidly evolving atmospheric features and auroral activity visible remotely: from Hubble and from the world’s flagship ground-based telescopes. Now, however, it’s approaching Uranian solstice once again, which it will reach in 2028. This time, the opposite pole from 1986 is starting to face the Sun, and the planet, again, overall, will soon become largely featureless in appearance.

Therefore, when JWST takes its looks at Uranus, we’re seeing it as it’s finishing its transition from equinox-to-solstice, illuminating one pole, preferentially, but only obliquely: at an angle. What JWST saw was spectacular, and again, unprecedented since Voyager 2.

• Uranus currently displays a polar cap, although those high-altitude ices and clouds are beginning to dissipate due to their continuous exposure to sunlight.
• Surrounding that cap is a less dense region, where the cap is evaporating.
• Dark lanes indicate further evidence of evaporation, punctuated by bright spots: Uranian storms.
• Then the inner Zeta (ζ) ring, followed by the α and β rings, the η ring, the thin δ, and the thick ε ring.
• After that, nine of Uranus’s prominent, inner moons appear: Bianca (#3) through Puck (#12), excluding only the too-small Cupid.
• And finally, the five major moons Miranda, Ariel, Umbriel, Titania, and Oberon can be seen.

The five largest moons of Uranus, in order from the innermost to the outermost, are Miranda, Ariel, Umbriel, Titania, and Oberon, with the latter two being the largest and first-discovered among Uranus’s moons. All of these moons and the innermost one rotate within a single degree of Uranus’s orbital plane except for Miranda, which is inclined by 4.3 degrees.

While JWST can continue to image Uranus for approximately the next 20 years or so from afar, the ideal goal is to go there, in situ, during the opposite conditions from when we were last there. We went during solstice last time, with Voyager 2, and therefore the next time, ideally, we’ll go to coincide with equinox. And it just so happens that the travel-time to Uranus, to enter an easily-insertable orbit around it with the appropriate gravity assists on the way there, involves about a 13 year travel-time. Under ideal conditions, after leaving Earth, you’d get a gravity assist from Jupiter, and then you fly past Uranus, dropping off (and inserting) an orbiter and possibly an atmospheric probe as well, and then you’d continue on, assisted by Uranus’s gravity, to Neptune, where you’d then have a second orbiter and possibly atmospheric probe, too.

Most orbiters that have been proposed, with or without probes, typically are slated for about 5 year science lifetimes. What should give us all tremendous hope for a future mission is that there will be a launch window to reach both worlds with a single mission, Uranus and Neptune alike, that align at once: in 2034. That’s when the conceptual ODINUS mission would send twin orbiters to both Uranus and Neptune simultaneously: arriving at Uranus in 2047, just two years before the next (2049) Uranian equinox, and then allowing an orbiter to arrive at Neptune about three years later: in 2050. The ODINUS mission itself, as originally proposed, would be a spectacular, joint venture between NASA and the ESA.

Uranus and its five major moons are depicted here in this montage of images acquired by the Voyager 2 mission in 1986. The five moons, from largest to smallest, are Ariel, Miranda, Titania, Oberon, and Umbriel. Puck, the 6th largest moon, is interior to all of them, and appears in the first and second JWST images of Uranus alongside these five. An orbiter and atmospheric probe, combined, could revolutionize our knowledge of this world.

In order to get the maximum amount of science possible out of the mission, you’d have to design your instruments properly. The orbiter would require multiple separate instruments on it designed to image and measure various properties of Uranus, its rings, and its moons. Uranus and Neptune should have enormous liquid oceans beneath their atmospheres, and an orbiter should be able to discover it for certain. The atmospheric probe would measure cloud-forming molecules, heat distribution, and how wind speed changed with depth. Originally, missions were focused on just one world at a time: Uranus as the higher-priority one (because it’s closer and has been studied for longer), and Neptune as the secondary one.

As proposed by the ESA’s Cosmic Vision program, the Origins, Dynamics, and Interiors of the Neptunian and Uranian Systems (ODINUS) mission goes even farther: expanding this concept to two twin orbiters, where we would send one to Neptune and one to Uranus. A launch window in 2034, where Earth, Jupiter, Uranus, and Neptune all align properly, could send them both off simultaneously. The scientific advantages of orbiters over a flyby mission are tremendous: longer observing times over much longer temporal baselines, the ability to focus on multiple targets over time, and the ability to discover features you may not have even anticipated would be there. Its proposed suite of six-to-eight instruments would not just take images and spectra, but seismic, magnetic, and ion measurements. The only additional costs are in terms of fuel, and enabling your orbiting spacecraft to perform burns, slow down, and enter and maintain stable orbits. The deluge of science that you get from remaining around a planet, long term, more than makes up for those increased costs.

A Plutonium-238 oxide pellet glowing from its own heat. Also produced as a by-product of nuclear reactions, Pu-238 is the radionuclide used to power deep-space vehicles, from the Mars Curiosity Rover to the ultra-distant Voyager spacecraft. It is most useful very far from the Sun, and Pu-238 also powered the Cassini and Galileo missions.

The current limitations on a mission like this don’t come from technical accomplishments; the technology exists to do it today. The difficulties are a combination of:

• political, arising from NASA’s finite, limited, and threatened budget,
• physical, because even with low-cost, heavy payload launch vehicles, we can still only send a limited amount of overall mass to the outer Solar System,
• and practical, because at these incredible distances from the Sun, solar panels will not power a sustained mission.

That practical limitation requires a power source of radioactive isotopes, with the radioisotope thermoelectric generator (RTG) Plutonium-238 serving as our preferred source for such missions.

However, most places in the world stopped producing Pu-238 back in the 20th century, and if we want enough to power a dual orbiter mission to Uranus and Neptune by the time the launch window arrives in 2034, we should really start producing it now. For the New Horizons mission to Pluto, an orbiter would have been a much more challenging mission strategy; New Horizons was too small and its speed was far too great, plus Pluto’s mass is quite low for attempting an orbital insertion. But for Neptune and Uranus, particularly if we choose the right gravity assists from Jupiter (and possibly Saturn), this could be feasible.

A unique, dual mission to both Uranus and Neptune could be launched in 2034, allowing us to fill in the biggest gaps in our knowledge of the Solar System: the gaps of what’s truly happening on and around our final two planets. The only way we’ll find out is if we dare and go look at what’s out there.

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Trundling along the ecliptic in Virgo, our satellite hangs near the bright star Spica in the evening sky.

Most supernovae are the explosive deaths of massive stars, but one important variety comes from an unassuming source. White dwarfs, the small, inactive cores left over after stars like our Sun burn out their nuclear fuel, can produce what astronomers call a Type Ia supernova.

“The explosions of white dwarfs play a crucial role in astronomy,” says Priyam Das, a PhD student at the University of New South Wales Canberra, Australia, who led the study on SNR 0509-67.5 published today in Nature Astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood. “Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved,” he adds.

All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion. However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass.

Now, astronomers have captured a new image that proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead. In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.

Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.

Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says these results show “a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature.” The team were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.

Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their predictable brightness — no matter how far away they are — helps astronomers to measure distances in space. Using them as a cosmic measuring tape, astronomers discovered the accelerating expansion of the Universe, a discovery that won the Physics Nobel Prize in 2011. Studying how they explode helps us to understand why they have such a predictable brightness.

Das also has another motivation to study these explosions. “This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,” he says, describing the “beautifully layered structure” that a supernova creates. For him, “revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.”

This research was presented in a paper to appear in Nature Astronomy titled “Calcium in a supernova remnant shows the fingerprint of a sub-Chandrasekhar mass explosion.”

The team is composed of P. Das (University of New South Wales, Australia [UNSW] & Heidelberger Institut für Theoretische Studien, Heidelberg, Germany [HITS]), I. R. Seitenzahl (HITS), A. J. Ruiter (UNSW & HITS & OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Hawthorn, Australia & ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions), F. K. Röpke (HITS & Institut für Theoretische Astrophysik, Heidelberg, Germany & Astronomisches Recheninstitut, Heidelberg, Germany), R. Pakmor (Max-Planck-Institut für Astrophysik, Garching, Germany [MPA]), F. P. A. Vogt (Federal Office of Meteorology and Climatology – MeteoSwiss, Payerne, Switzerland), C. E. Collins (The University of Dublin, Dublin, Ireland & GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany), P. Ghavamian (Towson University, Towson, USA), S. A. Sim (Queen’s University Belfast, Belfast, UK), B. J. Williams (X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, USA), S. Taubenberger (MPA & Technical University Munich, Garching, Germany), J. M. Laming (Naval Research Laboratory, Washington, USA), J. Suherli (University of Manitoba, Winnipeg, Canada), R. Sutherland (Australian National University, Weston Creek, Australia), and N. Rodríguez-Segovia (UNSW).

Geologists from The University of Hong Kong (HKU) have made a breakthrough in understanding how the Earth’s early continents formed during the Archean time, more than 2.5 billion years ago. Their findings, recently published in Science Advances, suggest that early continental crust likely formed through deep Earth processes called mantle plumes, rather than the plate tectonics that shape continents today.

A New Perspective on Earth’s Early Crust

Unlike other planets in our solar system, Earth is a unique planet with continental crust—vast landmasses with granitoid compositions that support life. However, the origin of these continents has remained a mystery. Scientists have long debated whether early continental crust formed through plate tectonics, i.e., the subduction and collision of giant slabs of Earth’s crust, or through other processes that do not involve plate movement.

This study, led by Drs Dingyi ZHAO and Xiangsong WANG in Mok Sau-King Professor Guochun ZHAO’s Early Earth Research Group at the HKU Department of Earth and Planetary Sciences, together with international collaborators, has uncovered strong evidence that a distinct geodynamic mechanism shaped the Earth’s formative years. Rather than the plate tectonic processes we see today, the research points to a regime dominated by mantle plumes—towering columns of hot, molten rock ascending from deep within the Earth. It also identifies a phenomenon known as sagduction, wherein surface rocks gradually descend under their weight into the planet’s hotter, deeper layers. These findings shed new light on the dynamic processes that governed the early evolution of Earth’s lithosphere.

Studying Ancient Rocks to Understand the Deep Past

The team analysed ancient granitoid rocks called TTGs (tonalite–trondhjemite–granodiorite), which make up a large part of the oldest continental crust. These rocks, found in northern China, date back around 2.5 billion years. Using advanced techniques, the researchers studied tiny minerals within the rocks, known as zircons, which preserve chemical signatures from the time the rocks were formed.

By measuring the water content and oxygen isotope composition of these zircons, the team found that the rocks were formed in dry, high-temperature environments, unlike those typically found in zones where tectonic plates collide and one sinks below the other (subduction zones). The oxygen signatures also indicate a mixture of molten oceanic rocks and sediments, consistent with rocks formed above mantle plumes rather than subduction zones.

The researchers proposed a two-stage model to explain their findings:

1. Around 2.7 billion years ago, a mantle plume caused thick piles of basalt (Fe- and Mg-rich volcanic rock) to form on the seafloor.
2. Then, around 2.5 billion years ago, another mantle plume brought heat that caused the lower parts of these basalts to melt partially. This process produced the lighter TTG rocks that eventually formed continental crust.

Implications for Earth and Planetary Science

“Our results provide strong evidence that Archean continental crust did not have to be formed through subduction,” explained Dr Dingyi Zhao, postdoctoral fellow of the Department of Earth and Planetary Sciences and the first author of the paper. “Instead, a two-stage process involving mantle plume upwelling and gravitational sagduction of greenstones better explains the geochemical and geological features observed in the Eastern Block.”

The study distinguishes between two coeval Archean TTG suites—one plume-related and the other arc-related— by comparing their zircon water contents and oxygen isotopes. Professor Guochun Zhao emphasised “The TTGs from the Eastern Block contain markedly less water than those formed in a supra-subduction zone in the Trans-North China Orogen, reinforcing the interpretation of a non-subduction origin.”

“This work is a great contribution to the study of early Earth geodynamics,” co-author Professor Fang-Zhen Teng from the University of Washington added. “Our uses of zircon water and oxygen isotopes have provided a powerful new window into the formation and evolution of early continental crust.”

This study not only provides new insights into understanding the formation of Archean continental crust, but also highlights the application of water-based proxies in distinguishing between tectonic environments. It contributes to a growing body of evidence that mantle plumes played a major role in the formation of the early continental crust.

Journal paper: A two-stage mantle plume–sagduction origin of Archean continental crust revealed by water and oxygen isotopes of TTGs, by Dingyi Zhao et al., Science Advances (2025). DOI: 10.1126/sciadv.adr9513

The intricate, hidden processes that sustain coral life are being revealed through a new microscope developed by scientists at UC San Diego’s Scripps Institution of Oceanography.

The diver-operated microscope — called the Benthic Underwater Microscope imaging PAM, or BUMP — incorporates pulse amplitude modulated (PAM) light techniques to offer an unprecedented look at coral photosynthesis on micro-scales. 

In a new study, researchers describe how the BUMP imaging system makes it possible to study the health and physiology of coral reefs in their natural habitat, advancing longstanding efforts to uncover precisely why corals bleach.

Engineers and marine researchers in the Jaffe Lab for Underwater Imaging at Scripps Oceanography designed and built the cutting-edge microscope with funding from the U.S. National Science Foundation. The microscope is already yielding new insights into the relationship between corals and the symbiotic microalgae that support their health, revealing for the first time how well individual algae photosynthesize within coral tissue. 

Their findings were published July 3 in the journal Methods in Ecology and Evolution.

“This microscope is a huge technological leap in the field of coral health assessment,” said Or Ben-Zvi, a postdoctoral researcher at Scripps Oceanography and lead author of the study. “Coral reefs are rapidly declining, losing their photosynthetic symbiotic algae in the process known as coral bleaching. We now have a tool that allows us to examine these microalgae within the coral tissue, non-invasively and in their natural environment.” 

Corals are reef-building animals that can’t photosynthesize on their own. Instead, they rely on microalgae living inside their tissues to do it for them. These symbiotic algae use sunlight, carbon dioxide and water to produce oxygen and energy-rich sugars that support coral growth and reef formation. 

At just 10 micrometers across, or about one-tenth the width of a human hair, these algae are far too small to be seen with the naked eye. When corals are stressed by warming waters or poor environmental conditions, they lose these microalgae, leading to a pale appearance (“coral bleaching”) and eventual starvation of the coral. Although this process is known, scientists don’t fully understand why, and it hasn’t been possible to study at appropriate scales in the field — until now.

“The microscope facilitates previously unavailable, underwater observations of coral health, a breakthrough made possible thanks to the National Science Foundation and its critical investment in technology development,” said Jules Jaffe, a research oceanographer at Scripps and co-author of the study. “Without continued federal funding, scientific research is jeopardized. In this case, NSF funding allowed us to fabricate a device so we can solve the physiological mystery of why corals bleach, and ultimately, use these insights to inform remediation efforts.”

The new imaging system builds upon previous technology developed by the Jaffe Lab, notably the Benthic Underwater Microscope, or BUM, from 2016. The main component of the BUMP is a microscope unit that is controlled via a touch screen and powered by a battery pack. Through an array of high-magnification lenses and focused LED lights, the microscope captures vivid color and fluorescence images and videos, and it now has the ability to measure photosynthesis and map it in higher resolution via focal scans.

With this tool, scientists are literally shining a light on biological processes underwater, using PAM light measurement techniques to visualize fluorescence and measure photosynthesis, and using imaging to create high-resolution 3D scans of corals.

When viewing the corals under the microscope, the red fluorescence of corals is attributed to the presence of chlorophyll, a photosynthetic pigment in the microalgae. With the PAM technique, the red fluorescence is measured, providing an index of how efficiently the microalgae are using light to produce sugars. The cyan/green fluorescence, concentrated around specific areas such as the mouth and tentacles of the coral, is attributed to special fluorescent proteins produced by the corals themselves and play multiple roles in the coral’s life functions.

The tool is small enough to fit in a carry-on suitcase and light enough for a diver to transport to the seafloor without requiring ship-based assistance. In collaboration with the Smith Lab at Scripps Oceanography, Ben-Zvi, a marine biologist, tested and calibrated the instrument at several coral reef hot spots around the globe: Hawaii, the Red Sea and Palmyra Atoll.

Peering through the microscope, she was surprised by how active the corals were, noting that they changed their volume and shape constantly. Coral behavior that looks like kissing or fighting has been previously documented by the Jaffe Lab, and Ben-Zvi was able to add some new observations to the mix, such as seeing a coral polyp seemingly trying to capture or remove a particle that was passing by, by rapidly contracting its tentacles.

“The more time we spend with this microscope, the more we hope to learn about corals and why they do what they do under certain conditions,” said Ben-Zvi. “We are visualizing photosynthesis, something that was previously unseen at the scales we are examining, and that feels like magic.”

Because scientists can bring the instrument directly into underwater study sites, their work is non-invasive — they don’t need to collect samples or even touch the corals.

“We get a lot of information about their health without the need to interrupt nature,” said Ben-Zvi. “It’s similar to a nurse who takes your pulse and tells you how well you’re doing. We’re checking the coral’s pulse without giving them a shot or doing an intrusive procedure on them.”

The researchers said that data collected with the new microscope can reveal early warning signs that appear before corals experience irreversible damage from global climate change events, such as marine heat waves. These insights could help guide mitigation strategies to better protect corals.

Beyond corals, the tool has widespread potential for studying other small-scale marine organisms that photosynthesize, such as baby kelp. Several researchers at Scripps Oceanography are already using the BUMP imaging system to study the early life stages of the elusive giant kelp off California.

“Since photosynthesis in the ocean is important for life on earth, a host of other applications are imaginable with this tool, including right here off the coast of San Diego,” said Jaffe.

In addition to Ben-Zvi and Jaffe, this study was co-authored by Paul Roberts — formerly with Scripps Oceanography and now at the Monterey Bay Aquarium Research Institute — along with Dimitri Deheyn, Pichaya Lertvilai, Devin Ratelle, Jennifer Smith, Joseph Snyder and Daniel Wangpraseurt of Scripps Oceanography.

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Journal

Methods in Ecology and Evolution

Method of Research

Observational study

Subject of Research

Animals

Article Title

The Benthic Underwater Microscope Imaging PAM (BUMP): A Non-invasive Tool for In Situ Assessment of Microstructure and Photosynthetic Efficiency

Article Publication Date

3-Jul-2025