Category: 7. Science

The spacecraft first headed to gas giant Jupiter for a gravity assist in 2007, in a maneuver which would increase its velocity by around 14,000 kilometers per hour (9,000 miles per hour). As it did so, it imaged Jupiter’s moons Io, Europa, and Ganymede, before heading towards Pluto at its new zippy speed of around 300 million miles per year.

Arriving at its primary target in 2015, the spacecraft collected data on Pluto and its moons Charon, Nix, Hydra, Kerberos, and Styx. 

“Data from New Horizons clearly indicated that Pluto and its satellites were far more complex than imagined, and scientists were particularly surprised by the degree of current activity on Pluto’s surface,” NASA explained of the mission. “The atmospheric haze and lower than predicted atmospheric escape rate forced scientists to fundamentally revise earlier models of the system.”

But the spacecraft was not done yet. Following the Pluto flyby, NASA redirected it towards an object in the Kuiper belt, around 6.4 billion kilometers (4 billion miles) from Earth. When it arrived in 2019, the object became the most distant object ever visited by a spacecraft.

The object was officially named Arrokoth in 2019 after the word for “sky” in the Powhatan/Algonquian language.

“The name ‘Arrokoth’ reflects the inspiration of looking to the skies and wondering about the stars and worlds beyond our own,” Alan Stern, New Horizons principal investigator from Southwest Research Institute, Boulder, Colorado, said in a statement at the time. “That desire to learn is at the heart of the New Horizons mission, and we’re honored to join with the Powhatan community and people of Maryland in this celebration of discovery.”

Arrokoth is a contact binary, with one lobe in contact with a smaller lobe, resembling a space snowman. The two lobes are believed to have clumped together under the force of gravity, but this closeup view of the asteroid revealed a few mysteries.

“What we’ve learned after sitting down and scratching our heads a little bit is that it’s what we call a ‘cold classical Kuiper Belt’ object,” New Horizons mission scientist Carey Lisse told the BBC’s Sky at Night magazine.

“It’s not cold because it’s far from the Sun; it’s dynamically cold. Its orbit has been pretty much the same for the entire history of the Solar System.”

These “cold” objects make up around a third of the Kuiper belt, with their circular orbits indicating that they haven’t been disturbed too much by the giant planets of the Solar System.

The team believes that Arrokoth is a “primordial” object, being largely unaffected by other objects in the past 4.6 billon years. That makes it pretty useful for studying the early Solar System, though heating can still affect the object at its surface, and perhaps as much as 10 meters (32 feet) deep.

One interesting aspect of the object, studied since New Horizon’s brief visit, is how the two lobes came together. 

“They are just touching each other, it’s like they are kissing, or if they were spacecraft they would be docking,” New Horizons co-investigator William McKinnon explained to Sky and Telescope. “There is no evidence that the merger of these two lobes was at all violent.”

According to that team, the two objects must have come together very slowly indeed, impacting at relative speeds of less than 3 meters per second. Others have put the velocity of impact at even lower. 

“We find that the individual mapped mounds on Arrokoth’s larger lobe, Wenu, are consistent with the merger or assembly of discrete, similarly sized multi-km-scale planetesimals from Arrokoth’s natal collapse cloud,” another recent team, which looked closely at mounds on the object, explained in their paper. 

“Our numerical calculations of collisional mergers of precursor bodies indicate that normal impact speeds ≲1 m/s are necessary to preserve the shapes of the individual subunits, using gravel friction parameters.”

Further study of such objects could tell us a lot about the formation of the Solar System. While no further trips are planned to Arrokoth, New Horizons is still operational.

“The New Horizons mission has a unique position in our solar system to answer important questions about our heliosphere and provide extraordinary opportunities for multidisciplinary science for NASA and the scientific community,” Nicola Fox, associate administrator for NASA’s Science Mission Directorate in Washington, said in a 2023 statement. “The agency decided that it was best to extend operations for New Horizons until the spacecraft exits the Kuiper Belt, which is expected in 2028 through 2029.” 

If another suitable target can be identified soon, New Horizons may be able to take a closer look at it, revealing further details of the Kuiper belt.

Earth’s deepest layers were not always solid rock blanketing a molten core. New simulations show a hidden sea of magma pooled above the core during the planet’s chaotic youth and how it still shapes the underground landscape today.

Charles‑Édouard Boukaré, a planetary physicist at York University, guided the work and argues that the ancient melt layer, or basal magma ocean, was an unavoidable consequence of early cooling. 

“Another way to say this is there is a memory,” Boukaré said, explaining that the planet’s interior still remembers its fiery beginnings.

Modeling the infant Earth

The research team combined isotope data from ancient rocks with modern seismic images to build a three‑dimensional model of a newborn planet.

Their code tracked how iron‑rich liquid separated from lighter crystal mush and trickled to the bottom of the mantle.

Even when they forced crystallization to start in mid‑mantle zones, dense melt still slid downward, proving that the deep pool forms, no matter where solidification begins.

The result overturns earlier one‑directional models that made the mantle freeze from the core upward.

The simulations reproduced present‑day mantle temperatures and predicted a lingering layer of melt up to 60 miles (96 kilometers) thick.

That prediction matches tiny signals in seismic data that hint at pockets of extraordinary heat above the core.

Heat flow kept Earth’s core liquid

Cooling crust near the surface formed the first minerals, but their extra weight made them plunge back into the mantle.

Most solidified crystals remelted on the trip down, yet some carried shallow chemical signatures that are now buried nearly 1,800 miles (2,900 kilometers) deep.

Iron oxide lowered the melting point of these sinking masses and helped them merge into the basal ocean. Heat flowing out of Earth’s core kept the iron‑rich mixture liquid long after the rest of the mantle stiffened into rock.

Because the melt is denser than the surrounding solids, it refuses to rise and cool.

That quirk sealed in a reservoir of incompatible elements such as neodymium and tungsten, explaining why modern lava sometimes carries ancient isotopic fingerprints.

Clues from mantle blobs

Seismologists have mapped two continent‑sized zones beneath Africa and the Pacific where earthquake waves slow sharply.

These large, low‑shear velocity provinces might be the frozen rims of the primeval ocean, dating back more than 4.4 billion years.

Alternative theories say the blobs are piles of sunken ocean crust recycled by plate tectonics. Yet the volume and dense, iron‑enriched makeup of the blobs fit the basal magma ocean story far better than crustal recycling alone.

If the blobs truly are relics of early melt, they could act as anchors that pin mantle plumes in place, explaining the long‑lived volcanic tracks that dot the Pacific seafloor.

Their presence also helps seismologists interpret odd, low‑velocity patches found near Earth’s core–mantle boundary worldwide.

Earth’s core drives convection

Heat leaving the core drives convection that powers the geodynamo, the engine behind Earth’s magnetic field. A thick, insulating sheet of iron‑rich melt alters that heat flow and could modulate magnetic strength over tens of millions of years.

“Continent drift might affect the location of tectonic plates,” notes Boukaré, hinting that the drift could partially reflect the deep ocean’s rhythm of currents. Changes in melt thickness also tweak how stiff slabs sink and how buoyant plumes rise. 

Isolated melt pockets may even lubricate slab edges, letting plates slide with less friction. That effect could explain why subduction zones sometimes shift along straight lines rather than wandering like rivers.

Chemical prints in ancient rocks

Isotopic ratios of samarium–neodymium and lutetium–hafnium vary subtly in rocks that are older than 3 billion years.

The variations match the signature expected when shallow crystals rain into a deep, iron‑saturated melt, then remix into later lavas.

Some Archean basalts in western Greenland preserve these signals, confirming that early differentiation products were never fully erased by later convection.

The model reconciles that evidence with the fact that most upper mantle rocks look chemically uniform today.

Geochemists once limited the amount of bridgmanite crystallization because they feared it would skew surface isotopes, but the new work shows that shallow and deep processes can cancel each other’s signals. This finding opens room for more extensive early mantle stratification than previously thought.

Echoes on other worlds

It is theorized that Mars lost its magnetic shield early, and Venus never developed plate tectonics, outcomes that may reflect how long their own basal oceans survived.

Running Boukaré’s code with Martian gravity produces a melt layer that freezes quickly, starving the core of heat and ending dynamo action.

Super‑Earth exoplanets, with stronger gravity and thicker mantles, may hold basal oceans far longer.

That persistence could dampen surface volcanism and help the planets retain atmospheres, parameters that astronomers use when ranking habitability.

Future questions about Earth’s core

Laboratory experiments that squeeze minerals to core pressures are planned to test how truly dense molten iron‑silicate mixtures become. Those results will refine melt‑mobility numbers in the next generation of mantle models.

Seismologists are also hunting for ultrasonic echoes that bounce off the melt’s upper surface, a signal that would prove the ocean still exists today. Any detection would transform theories about mantle convection and core cooling in one stroke.

Looking ahead, the team plans to fold more trace elements into the model and simulate mantle overturn events triggered by giant impacts.

Those runs could reveal whether the basal ocean ever mixed completely or still hides a liquid heart.

Success in either search would ripple into planetary science, informing models of exoplanets and guiding missions that probe the deep interiors of rocky worlds.

The next decade of experiments and observations could turn the idea of a lasting magma sea from theory into accepted geology.

The study is published in Nature.

Photo credits: @Sylvain Petitgirard/University of Bayreuth.

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BYLINE: Kitta MacPherson

Newswise — A Rutgers-led team of scientists has developed an eco-friendly, very stable, ultra-bright material and used it to generate deep-blue light (emission at ~450 nm) in a light-emitting diode (LED), an energy-efficient device at the heart of all major lighting systems.

The new copper-iodide hybrid emitter materials are expected to contribute to the advancement of blue LED technologies because of their excellent qualities, according to the scientists who pioneered the discovery. The process that produces the material is described in the science journal Nature.

“Deep-blue LEDs are at the heart of today’s energy-efficient lighting technologies,” said Jing Li, a Distinguished Professor and Board of Governors Professor of Chemistry and Chemical Biology in the Department of Chemistry and Chemical Biology in the School of Arts and Sciences who leads the study. “However, existing options often present issues with stability, scalability, cost, efficiency or environmental concerns due to the use of toxic components. This new copper-iodide hybrid offers a compelling solution, leveraging its nontoxicity, robustness and high performance.”

LEDs are lighting devices that use special materials called semiconductors to turn electricity into light in an efficient and durable way. Blue LEDS were discovered in the early 1990s and earned their discoverers the 2014 Nobel Prize in physics.

Blue LEDs are particularly important because they are used to create white light and are essential for general lighting applications.

Li and her colleagues at Rutgers collaborated with scientists at Brookhaven National Laboratory and four other research teams representing national and international institutions in the effort to work on new materials that would improve upon existing blue LEDs.

The researchers involved in the study found a way to make blue LEDs more efficient and sustainable by using a new type of hybrid material: a combination of copper iodide with organic molecules.

“We wanted to create new kind of materials that give very bright deep-blue light and use them to fabricate LEDs at lower cost than current blue LEDs,” Li said.

The new hybrid copper-iodide semiconductor offers a number of advantages over some other materials used in LEDs, scientists said. Lead-halide perovskites, while cost effective, contain lead, which is toxic to humans, as well as have issues with stability, due to their sensitivity to moisture and oxygen. Organic LEDs (OLEDs) are flexible and potentially efficient but may lack structural and spectral stability, meaning they can degrade quickly and lose their color quality over time. Colloidal quantum dots perform well mainly in green and lower-energy LEDs and are often cadmium-based, which may raise toxicity concerns. Phosphorescent organic emitters may be costly and complex to synthesize.

“The new material provides an eco-friendly and stable alternative to what currently exists, addressing some of these issues and may potentially advance LED technology,” Li said.

The hybrid copper-iodide material possesses favorable qualities such as a very high photoluminescence quantum yield of about 99.6%, meaning it converts nearly all the photoenergy it receives into blue light. Blue LEDs made from this material have reached a maximum external quantum efficiency (the ratio between the number of emitted photons and number of injected electrons) of 12.6%, among the highest achieved so far for solution-processed deep-blue LEDs.

Not only are these LEDs bright, they also last longer compared with many others. Under normal conditions, they have an operational half-lifetime of about 204 hours, meaning they can keep shining for a good amount of time before their brightness starts to fade. In addition, the material works well in larger-scale applications. The researchers successfully created a larger device that maintains high efficiency, showing that this material has potential to be used in real-world applications.

The secret to the material’s impressive performance lies in an innovative technique developed by the scientists called dual interfacial hydrogen-bond passivation. The manufacturing technique significantly boosts the performance of the LEDs four-fold.

“Our processing method minimizes defects that can impede the movement of electric charges at the interface of these hybrid materials,” said Kun Zhu, a former graduate student and postdoctoral associate at Rutgers who is now at the Max Planck Institute in Germany and is the paper’s first author. “This approach could be a versatile strategy for generating high-performance LEDs.”

If the LED can be imagined as a sandwich with different layers, each layer has a specific job, such as emitting light or transporting electrons and holes. Sometimes, the emissive layer doesn’t interact perfectly with its interface layers, which can reduce efficiency or shorten lifespan. The technique eliminates such problems by forming hydrogen bonds between the layers to create better connections.

“Overall, this type of new material is paving the way for better, brighter and longer-lasting LEDs,” Li said.

Other Rutgers scientists contributing to the study included Deirdre O’Carroll, associate professor, and Nasir Javed, doctoral student, of the Department of Chemistry and Chemical Biology and Department of Materials Science and Engineering; and Sylvie Rangan, assistant research professor, and Leila Kasaei, postdoctoral research associate, of the Department of Physics and Astronomy.

The research was funded by the U.S. Department of Energy.

 Explore more of the ways Rutgers research is shaping the future.

A giant plasma plume dubbed “The Beast” was recently spotted dancing above the sun as it showered our home star with blobs of impossibly fast fire. The shapeshifting projection, which stretched more than 13 times wider than Earth, was the first of several sizable solar structures to emerge in recent days.

The animalistic mass appeared Saturday (July 12) over the northwestern limb of the sun, allowing photographers from around the world to snap some stunning shots, including Michael Jäger, who captured the plume from Martinsburg in Austria (see above); and Simon Metcalfe, who saw it from near his home in Gloucestershire, England (see below).

Researchers just got a step closer to understanding the origins of our solar system, with the discovery of an object orbiting the sun—dubbed “Ammonite.” The findings were recently published in the peer-reviewed scientific journal Nature Astronomy.

Ammonite, or its scientific name 2023 KQ14, is known as a sednoid, which is a type of cosmic body circling the sun beyond Neptune with a highly eccentric orbit. It’s only the fourth sednoid ever discovered. It comes as close as 66 astronomical units (AU) from the sun and as far away as 252 AU. One astronomical unit is equal to the average distance between Earth and the sun, or about 93 million miles.

Ammonite was discovered by the survey project “FOSSIL” (Formation of the Outer Solar System: An Icy Legacy), which is led by researchers from Japan and Taiwan who explore the outer solar system to learn about its past. The research team used the powerful Subaru Telescope, located at the Mauna Kea Observatory in Hawaii. The telescope has wide-field imaging capabilities that are uniquely suited for scanning large patches of the sky for faint, slow-moving objects like Ammonite.

Computer simulations show that Ammonite’s orbit has remained stable for billions of years, unaffected by gravitational interactions with other solar system objects. This long-term stability makes Ammonite one of the best-preserved “fossils” of our solar system’s distant past, suggesting that it originates from the solar system’s early formation and retains a fossil record of the orbital configuration.

Ying-Tung Chen, one of the authors of the study and a support scientist at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), in Taiwan, said in a statement that while previously known sednoid objects all share roughly similar orbital orientations, Ammonite’s orbit is oriented in the opposite direction, suggesting that the outer solar system is more diverse and complex than previously thought.

What caused this clustering of objects is still unclear, with scientists hypothesizing about the possibility of a passing star or an ejected planet.

“The significance of discovering Ammonite goes far beyond adding one more distant object,” Shiang-Yu Wang, one of the study’s authors and a research fellow at ASIAA, said in a statement. “Ammonite’s orbit tells us that something sculpted the outer solar system very early on. Whether it was a passing star or a hidden planet, this discovery brings us closer to the truth.”

Using the James Webb Space Telescope (JWST), astronomers have discovered an oddball galaxy, dubbed the Infinity Galaxy, that could be host to a “direct collapse black hole.” That is, a black hole originally created directly from a vast cloud of collapsing gas and dust rather than a dying star.

The Infinity Galaxy gets its name from the fact that its shape resembles an infinity symbol (a sideways 8) with two red lobes or “nuclei.” This shape is thought to have arisen because the Infinity Galaxy was formed as two disk galaxies engaged in a head-on collision.

International researchers have, for the first time, pinpointed the moment when planets began to form around a star beyond the Sun. Using the ALMA telescope, in which the European Southern Observatory (ESO) is a partner, and the James Webb Space Telescope, they have observed the creation of the first specks of planet-forming material — hot minerals just beginning to solidify. This finding marks the first time a planetary system has been identified at such an early stage in its formation and opens a window to the past of our own Solar System.

“For the first time, we have identified the earliest moment when planet formation is initiated around a star other than our Sun,” says Melissa McClure, a professor at Leiden University in the Netherlands and lead author of the new study, published today in Nature.

Co-author Merel van ‘t Hoff, a professor at Purdue University, USA, compares their findings to “a picture of the baby Solar System”, saying that “we’re seeing a system that looks like what our Solar System looked like when it was just beginning to form.”

This newborn planetary system is emerging around HOPS-315, a ‘proto’ or baby star that sits some 1300 light-years away from us and is an analogue of the nascent Sun. Around such baby stars, astronomers often see discs of gas and dust known as ‘protoplanetary discs’, which are the birthplaces of new planets. While astronomers have previously seen young discs that contain newborn, massive, Jupiter-like planets, McClure says, “we’ve always known that the first solid parts of planets, or ‘planetesimals’, must form further back in time, at earlier stages.”

In our Solar System, the very first solid material to condense near Earth’s present location around the Sun is found trapped within ancient meteorites. Astronomers age-date these primordial rocks to determine when the clock started on our Solar System’s formation. Such meteorites are packed full of crystalline minerals that contain silicon monoxide (SiO) and can condense at the extremely high temperatures present in young planetary discs. Over time, these newly condensed solids bind together, sowing the seeds for planet formation as they gain both size and mass. The first kilometre-sized planetesimals in the Solar System, which grew to become planets such as Earth or Jupiter’s core, formed just after the condensation of these crystalline minerals.

With their new discovery, astronomers have found evidence of these hot minerals beginning to condense in the disc around HOPS-315. Their results show that SiO is present around the baby star in its gaseous state, as well as within these crystalline minerals, suggesting it is only just beginning to solidify. “This process has never been seen before in a protoplanetary disc — or anywhere outside our Solar System,” says co-author Edwin Bergin, a professor at the University of Michigan, USA.

These minerals were first identified using the James Webb Space Telescope, a joint project of the US, European and Canadian space agencies. To find out where exactly the signals were coming from, the team observed the system with ALMA, the Atacama Large Millimeter/submillimeter Array, which is operated by ESO together with international partners in Chile’s Atacama Desert.

With these data, the team determined that the chemical signals were coming from a small region of the disc around the star equivalent to the orbit of the asteroid belt around the Sun. “We’re really seeing these minerals at the same location in this extrasolar system as where we see them in asteroids in the Solar System,” says co-author Logan Francis, a postdoctoral researcher at Leiden University.

Because of this, the disc of HOPS-315 provides a wonderful analogue for studying our own cosmic history. As van ‘t Hoff says, “this system is one of the best that we know to actually probe some of the processes that happened in our Solar System.” It also provides astronomers with a new opportunity to study early planet formation, by standing in as a substitute for newborn solar systems across the galaxy.

ESO astronomer and European ALMA Programme Manager Elizabeth Humphreys, who did not take part in the study, says: “I was really impressed by this study, which reveals a very early stage of planet formation. It suggests that HOPS-315 can be used to understand how our own Solar System formed. This result highlights the combined strength of JWST and ALMA for exploring protoplanetary discs.”

More information

This research was presented in the paper “Refractory solid condensation detected in an embedded protoplanetary disk” ( doi:10.1038/s41586-025-09163-z ) to appear in Nature.

The team is composed of M. K. McClure (Leiden Observatory, Leiden University, The Netherlands [Leiden]), M. van ‘t Hoff (Department of Astronomy, The University of Michigan, Michigan, USA [Michigan] and Purdue University, Department of Physics and Astronomy, Indiana, USA), L. Francis (Leiden), Edwin Bergin (Michigan), W.R. M. Rocha (Leiden), J. A. Sturm (Leiden), D. Harsono (Institute of Astronomy, Department of Physics, National Tsing Hua University, Taiwan), E. F. van Dishoeck (Leiden), J. H. Black (Chalmers University of Technology, Department of Space, Earth and Environment, Onsala Space Observatory, Sweden), J. A. Noble (Physique des Interactions Ioniques et Moléculaires, CNRS, Aix Marseille Université, France), D. Qasim (Southwest Research Institute, Texas, USA), E. Dartois (Institut des Sciences Moléculaires d’Orsay, CNRS, Université Paris-Saclay, France.)

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.

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High above us, particles from the Sun hurtle toward Earth, colliding with the upper atmosphere and creating powerful explosions in a murky process called magnetic reconnection. A single magnetic reconnection event can release as much energy as the entire United States uses in a day.

NASA’s new TRACERS (Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites) mission will study magnetic reconnection, answering key questions about how it shapes the impacts of the Sun and space weather on our daily lives.

The TRACERS spacecraft are slated to launch no earlier than late July 2025 aboard a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California. The two TRACERS spacecraft will orbit Earth to study how the solar wind — a continuous outpouring of electrically charged particles from the Sun — interacts with Earth’s magnetic shield, the magnetosphere.

As solar wind flows out from the Sun, it carries the Sun’s embedded magnetic field out across the solar system. Reaching speeds over one million miles per hour, this soup of charged particles and magnetic field plows into planets in its path.

“Earth’s magnetosphere acts as a protective bubble that deflects the brunt of the solar wind’s force. You can think of it as a bar magnet that’s rotating and floating around in space,” said John Dorelli, TRACERS mission science lead at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “As the solar wind collides with Earth’s magnetic field, this interaction builds up energy that can cause the magnetic field lines to snap and explosively fling away nearby particles at high speeds — this is magnetic reconnection.”

Openings in Earth’s magnetic field at the North and South Poles, called polar cusps, act as funnels allowing charged particles to stream down towards Earth and collide with atmospheric gases. These phenomena are pieces of the space weather system that is in constant motion around our planet — whose impacts range from breathtaking auroras to disruption of communications systems and power grids. In May 2024, Earth experienced the strongest geomagnetic storm in more than 20 years, which affected high-voltage power lines and transformers, forced trans-Atlantic flights to change course, and caused GPS-guided tractors to veer off-course.

The TRACERS mission’s twin satellites, each a bit larger than a washing machine, will fly in tandem, one behind the other, in a relatively low orbit about 360 miles above Earth. Traveling over 16,000 mph, each satellite hosts a suite of instruments to measure different aspects of extremely hot, ionized gas called plasma and how it interacts with Earth’s magnetosphere.

The satellites will focus where Earth’s magnetic field dips down to the ground at the North polar cusp. By placing the twin TRACERS satellites in a Sun-synchronous orbit, they always pass through Earth’s dayside polar cusp, studying thousands of reconnection events at these concentrated areas.

This will build a step-by-step picture of how magnetic reconnection changes over time and from Earth’s dayside to its nightside.

NASA’s TRICE-2 mission also studied magnetic reconnection near Earth, but with a pair of sounding rockets launched into the northern polar cusp over the Norwegian Sea in 2018.

“The TRICE mission took great data. It took a snapshot of the Earth system in one state. It proved that these instruments could make this kind of measurement and achieve this kind of science,” said David Miles, TRACERS principal investigator at the University of Iowa. “But the system’s more complicated than that. The TRACERS mission demonstrates how you can use multi-spacecraft technology to get a picture of how things are moving and evolving.”

Because previous missions could only take one measurement of an event per launch, too many changes in the region prevented forming a full picture. Following each other closely in orbit, the twin TRACERS satellites will provide multiple snapshots of the same area in rapid succession, spaced as closely as 10 seconds apart from each other, reaching a record-breaking 3,000 measurements in one year. These snapshots will build a picture of how the whole Earth system behaves in reaction to space weather, allowing scientists to better understand how to predict space weather in the magnetosphere.

The TRACERS mission will collaborate with other NASA heliophysics missions, which are strategically placed near Earth and across the solar system. At the Sun, NASA’s Parker Solar Probe closely observes our closest star, including magnetic reconnection there and its role in heating and accelerating the solar wind that drives the reconnection events investigated by TRACERS.

Data from recently launched NASA missions, EZIE (Electrojet Zeeman Imaging Explorer), studying electrical currents at Earth’s nightside, and PUNCH (Polarimeter to Unify the Corona and Heliosphere) studying the solar wind and interactions in Earth’s atmosphere, can be combined with observations from TRACERS. With research from these missions, scientists will be able to get a more complete understanding of how and when Earth’s protective magnetic shield can suddenly connect with solar wind, allowing the Sun’s material into Earth’s system.

“The TRACERS mission will be an important addition to NASA’s heliophysics fleet.” said Reinhard Friedel, TRACERS program scientist at NASA Headquarters in Washington. “The missions in the fleet working together increase understanding of our closest star to improve our ability to understand, predict, and prepare for space weather impacts on humans and technology in space.”

The TRACERS mission is led by David Miles at the University of Iowa with support from the Southwest Research Institute in San Antonio, Texas. NASA’s Heliophysics Explorers Program Office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the mission for the agency’s Heliophysics Division at NASA Headquarters in Washington. The University of Iowa, Southwest Research Institute, University of California, Los Angeles, and the University of California, Berkeley, all lead instruments on TRACERS that study changes in the magnetic field and electric field. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, manages the VADR (Venture-class Acquisition of Dedicated and Rideshare) contract.

by Desiree Apodaca
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Header Image:
An artist’s concept of the TRACERS mission, which will help research magnetic reconnection and its effects in Earth’s atmosphere.
Credits: Andy Kale

Doing NASA Science brings many rewards. But can taking part in NASA citizen science help your career? To find out, we asked participants in NASA’s Exoplanet Watch project about their experiences. In this project, amateur astronomers work together with professionals to track planets around other stars.

First, we heard from professional software programmers. Right away, one of them told us about getting a new job through connections made in the project.

“I decided to create the exoplanet plugin, [for citizen science] since it was quite a lot of manual work to check which transits were available for your location. The exoplanet plugin and its users got me in contact with the Stellar group… Through this group, I got into contact with a company called OurSky and started working for them… the point is, I created a couple of plugins for free and eventually got a job at an awesome company.”

Another participant talked about honing their skills and growing their confidence through Exoplanet Watch.

“There were a few years when I wasn’t actively coding. However, Exoplanet Watch rekindled that spark…. Participating in Exoplanet Watch even gave me the confidence to prepare again for a technical interview at Meta-despite having been thoroughly defeated the first time I tried.”

Teachers and teaching faculty told us how Exoplanet Watch gives them the ability to better convey what scientific research is all about – and how the project motivates students!

“Exoplanet Watch makes it easy for undergraduate students to gain experience in data science and Python, which are absolutely necessary for graduate school and many industry jobs.”

“Experience with this collaborative work is a vital piece of the workforce development of our students who are seeking advanced STEM-related careers or ongoing education in STEM (Science, Technology, Engineering, & Mathematics) fields after graduation… Exoplanet Watch, in this way, is directly training NASA’s STEM workforce of tomorrow by allowing CUNY (The City University of New York) students to achieve the science goals that would otherwise be much more difficult without its resources.”

One aspiring academic shared how her participation on the science team side of the project has given her research and mentorship experience that strengthens her resume.

“I ended up joining the EpW team to contribute my expertise in stellar variability… My involvement with Exoplanet Watch has provided me with invaluable experience in mentoring a broad range of astronomy enthusiasts and working in a collaborative environment with people from around the world. … Being able to train others, interact in a team environment, and work independently are all critical skills in any work environment, but these specific experiences have also been incredibly valuable towards building my portfolio as I search for faculty positions around the USA.”

There are no guarantees, of course. What you get out of NASA citizen science depends on what you put in. But there is certainly magic to be found in the Exoplanet Watch project. As one student said:

“Help will always be found at Hogwarts, to those who need it.” Exoplanet Watch was definitely Hogwarts for me in my career as an astronomer!”

Around 201 million years ago, acidification turned Earth’s oceans from cradles of life into harbingers of extinction.

New research from the University of St Andrews and the University of Birmingham has confirmed for the first time that a sharp and rapid drop in ocean pH directly contributed to a major extinction event. The cause? A massive surge in atmospheric carbon dioxide.

The study represents the first full reconstruction of ancient ocean pH using boron isotopes in fossil oysters. It shows that the acidification during the Triassic-Jurassic boundary was not only severe but prolonged.

Earth’s oceans thrived before the fall

In the seas, early modern corals, ichthyosaurs, ammonites, and bivalves thrived. Coral reefs flourished until the acidification triggered a “reef gap” – a period of reef absence that lasted hundreds of thousands of years. This collapse wasn’t subtle.

It reshaped marine ecosystems, reducing carbonate sedimentation and leaving many marine organisms unable to form shells or skeletons.

Using oysters from Lavernock Point, Wales, researchers detected a 0.29 unit or greater drop in ocean pH. It may have exceeded 0.41 units. This translates to more than a doubling of atmospheric CO₂, with levels climbing over 1300 ppm. For context, today’s CO₂ levels hover near 420 ppm.

Drastic changes, fast consequences

The pH drop happened in tandem with a sharp decline in the carbon isotope ratio (δ¹³C), known as the “main carbon isotope excursion (CIE).”

This points to an enormous carbon release event. The study’s authors estimate that over 10,000 gigatons of carbon may have entered the system, mainly from Earth’s mantle. These emissions likely came from volcanic activity as the supercontinent Pangaea began breaking apart.

“The geological record tells us that major CO₂ release transforms the face of our planet, acidifying the ocean, and causing mass extinction. We have to act fast to avoid these outcomes in our future,” said study co-author Dr. James Rae.

Volcanoes linked to ocean acidification

Using the cGENIE Earth system model, the researchers tested scenarios with different carbon sources. The model confirmed that the likely carbon input was mantle-derived.

The size and speed of the event eliminated methane clathrates as the dominant cause, although they may have contributed. The data also ruled out biomass burning and indicated that volcanic CO₂ and contact metamorphism played the lead roles.

Carbonate saturation dropped drastically. Marine organisms used to high-saturation seas struggled as saturation levels fell below safe thresholds.

Initial drop hit harder

Interestingly, the more catastrophic acidification may have happened earlier, during the “initial CIE”. Though no oyster samples span that exact interval, the data suggest that the initial event was faster and possibly two to three times more intense in terms of pH drop.

This would align with the wider collapse of carbonate sedimentation and widespread death of shell-building marine life.

Earth’s oceans slowly bounce back

Despite the devastation, ocean pH eventually recovered. Around 201.28 million years ago, pH levels began to rise again.

This rebound may have resulted from the emergence of silica-producing organisms. These organisms disrupted a process called reverse weathering.

This process had previously prolonged the high-CO₂, low-pH conditions by locking alkalinity away in clays. Its sudden stop helped restore ocean chemistry.

History warns of a repeat

“The mass extinction event during the Triassic-Jurassic period was over a much longer timeframe, whereas modern ocean acidification is happening at a much quicker rate,” said study co-author Dr. Sarah Greene.

“This warning from the past should give us fresh cause to step up efforts to reduce human greenhouse gas emissions that could otherwise see acidification reach or exceed levels seen during these mass extinction events.”

The data show this is not an isolated case. Ocean acidification has now been confirmed in at least three of Earth’s five mass extinctions. These include the Permian–Triassic, Toarcian, and now the Triassic–Jurassic.

According to the study, the observed pH drops in these events are strikingly similar in size to worst-case predictions for 2100 under IPCC’s RCP8.5 scenario.

Acid oceans could return to Earth

Mass extinctions don’t just come from space rocks or ice ages. Earth can end its own chapters when the carbon cycle breaks down.

The Triassic–Jurassic event tells us that prolonged CO₂ release, even from natural sources, can tip the balance. It can turn oceans hostile and trigger a global loss of life.

Today, the same process is unfolding, only much faster. The past offers no comfort. It offers a clear call to action.

The study is published in the journal Nature Communications.

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