A new study reveals that about 3.8 million years after the solar system's first solids formed, Jupiter was twice its current size with a magnetic field 50 times stronger, profoundly influencing the structure of the early solar system. Phys.Org reports: [Konstantin Batygin, professor of planetary science at Caltech] and [Fred C. Adams, professor of physics and astronomy at the University of Michigan] approached this question by studying Jupiter's tiny moons Amalthea and Thebe, which orbit even closer to Jupiter than Io, the smallest and nearest of the planet's four large Galilean moons. Because Amalthea and Thebe have slightly tilted orbits, Batygin and Adams analyzed these small orbital discrepancies to calculate Jupiter's original size: approximately twice its current radius, with a predicted volume that is the equivalent of over 2,000 Earths. The researchers also determined that Jupiter's magnetic field at that time was approximately 50 times stronger than it is today.

Adams highlights the remarkable imprint the past has left on today's solar system: "It's astonishing that even after 4.5 billion years, enough clues remain to let us reconstruct Jupiter's physical state at the dawn of its existence." Importantly, these insights were achieved through independent constraints that bypass traditional uncertainties in planetary formation models -- which often rely on assumptions about gas opacity, accretion rate, or the mass of the heavy element core. Instead, the team focused on the orbital dynamics of Jupiter's moons and the conservation of the planet's angular momentum -- quantities that are directly measurable.

Their analysis establishes a clear snapshot of Jupiter at the moment the surrounding solar nebula evaporated, a pivotal transition point when the building materials for planet formation disappeared and the primordial architecture of the solar system was locked in. The results add crucial details to existing planet formation theories, which suggest that Jupiter and other giant planets around other stars formed via core accretion, a process by which a rocky and icy core rapidly gathers gas. The findings have been published in the journal Nature Astronomy.

The Prossimo project (funded by the nonprofit Internet Security Research Group) seeks to "move the Internet's security-sensitive software infrastructure to memory safe code." Two years ago the Prossimo project made an announcement: they'd begun work on rav1d, a safer high performance AV1 decoder written in Rust, according to a new update: We partnered with Immunant to do the engineering work. By September of 2024 rav1d was basically complete and we learned a lot during the process. Today rav1d works well — it passes all the same tests as the dav1d decoder it is based on, which is written in C. It's possible to build and run Chromium with it.

There's just one problem — it's not quite as fast as the C version...

Our Rust-based rav1d decoder is currently about 5% slower than the C-based dav1d decoder (the exact amount differs a bit depending on the benchmark, input, and platform). This is enough of a difference to be a problem for potential adopters, and, frankly, it just bothers us. The development team worked hard to get it to performance parity. We brought in a couple of other contractors who have experience with optimizing things like this. We wrote about the optimization work we did. However, we were still unable to get to performance parity and, to be frank again, we aren't really sure what to do next.

After racking our brains for options, we decided to offer a bounty pool of $20,000 for getting rav1d to performance parity with dav1d. Hopefully folks out there can help get rav1d performance advanced to where it needs to be, and ideally we and the Rust community will also learn something about how Rust performance stacks up against C.
This drew a snarky response from FFmpeg, the framework that powers audio and video processing for everyone from VLC to Twitch. "Rust is so good you can get paid $20k to make it as fast as C," they posted to their 68,300 followers on X.com.

Thanks to the It's FOSS blog for spotting the announcement.

The only nuclear power plant still operating in Taiwan was shut down on Saturday, reports Japan's public media organization NHK: People in Taiwan have grown increasingly concerned about nuclear safety in recent years, especially after the 2011 nuclear disaster in Fukushima, northeastern Japan... Taiwan's energy authorities plan to focus more on thermoelectricity fueled by liquefied natural gas. They aim to source 20 percent of all electricity from renewables such as wind and solar power next year.
AFP notes that nuclear power once provided more than half of Taiwan's energy, with three plants operating six reactors across an island that's 394 km (245 mi) long and 144 km (89 mi) wide.

So the new move to close Taiwan's last reactor is "fuelling concerns over the self-ruled island's reliance on imported energy and vulnerability to a Chinese blockade," — though Taiwan's president insists the missing nucelar energy can be replace by new units in LNG and coal-fired plants: The island, which targets net-zero emissions by 2050, depends almost entirely on imported fossil fuel to power its homes, factories and critical semiconductor chip industry. President Lai Ching-te's Democratic Progressive Party has long vowed to phase out nuclear power, while the main opposition Kuomintang (KMT) party says continued supply is needed for energy security... [The Ma'anshan Nuclear Power Plant] has operated for 40 years in a region popular with tourists and which is now dotted with wind turbines and solar panels. More renewable energy is planned at the site, where state-owned Taipower plans to build a solar power station capable of supplying an estimated 15,000 households annually. But while nuclear only accounted for 4.2 percent of Taiwan's power supply last year, some fear Ma'anshan's closure risks an energy crunch....

Most of Taiwan's power is fossil fuel-based, with liquefied natural gas (LNG) accounting for 42.4 percent and coal 39.3 percent last year. Renewable energy made up 11.6 percent, well short of the government's target of 20 percent by 2025. Solar has faced opposition from communities worried about panels occupying valuable land, while rules requiring locally made parts in wind turbines have slowed their deployment.

Taiwan's break-up with nuclear is at odds with global and regional trends. Even Japan aims for nuclear to account for 20-22 percent of its electricity by 2030, up from well under 10 percent now. And nuclear power became South Korea's largest source of electricity in 2024, accounting for 31.7 percent of the country's total power generation, and reaching its highest level in 18 years, according to government data.... And Lai acknowledged recently he would not rule out a return to nuclear one day. "Whether or not we will use nuclear power in the future depends on three foundations which include nuclear safety, a solution to nuclear waste, and successful social dialogue," he said.
DW notes there's over 100,000 barrels of nuclear waste on Taiwan's easternmost island "despite multiple attempts to remove them... At one point, Taiwan signed a deal with North Korea so they could send barrels of nuclear waste to store there, but it did not work out due to a lack of storage facilities in the North and strong opposition from South Korea...

"Many countries across the world have similar problems and are scrambling to identify sites for a permanent underground repository for nuclear fuel. Finland has become the world's first nation to build one."

Thanks to long-time Slashdot reader AmiMoJo for sharing the news.

NASA engineers have successfully revived Voyager 1's backup thrusters, unused since 2004 and once considered defunct. Space.com reports: This remarkable feat became necessary because the spacecraft's primary thrusters, which control its orientation, have been degrading due to residue buildup. If its thrusters fail completely, Voyager 1 could lose its ability to point its antenna toward Earth, therefore cutting off communication with Earth after nearly 50 years of operation. To make matters more urgent, the team faced a strict deadline while trying to remedy the thruster situation. After May 4, the Earth-based antenna that sends commands to Voyager 1 -- and its twin, Voyager 2 -- was scheduled to go offline for months of upgrades. This would have made timely intervention impossible.

To solve the problem, NASA's team had to reactivate Voyager 1's long-dormant backup roll thrusters and then attempt to restart the heaters that keep them operational. If the star tracker drifted too far from its guide star during this process, the roll thrusters would automatically fire as a safety measure -- but if the heaters weren't back online by then, firing the thrusters could cause a dangerous pressure spike. So, the team had to precisely realign the star tracker before the thrusters engaged. Because Voyager is so incredibly distant, the team faced an agonizing 23-hour wait for the radio signal to travel all the way back to Earth. If the test had failed, Voyager might have already been in serious trouble. Then, on March 20, their patience was finally rewarded when Voyager responded perfectly to their commands. Within 20 minutes of receiving the signal, the team saw the thruster heaters' temperature soar -- a clear sign that the backup thrusters were firing as planned. "It was such a glorious moment. Team morale was very high that day," Todd Barber, the mission's propulsion lead at JPL, said in the statement. "These thrusters were considered dead. And that was a legitimate conclusion. It's just that one of our engineers had this insight that maybe there was this other possible cause, and it was fixable. It was yet another miracle save for Voyager."

Evidence is mounting for "a vast reservoir of liquid water" on Mars, according to a new article by Australian National University professor Hrvoje TkalÄiÄ and geophysics associate professor Weijia Sun from the Chinese Academy of Geological Sciences, announcing their recently published paper.

"Using seismic data from NASA's InSight mission, we uncovered evidence that the seismic waves slow down in a layer between 5.4 and 8 kilometres below the surface, which could be because of the presence of liquid water at these depths." Mars is covered in traces of ancient bodies of water. But the puzzle of exactly where it all went when the planet turned cold and dry has long intrigued scientists... Billions of years ago, during the Noachian and Hesperian periods (4.1 billion to 3 billion years ago), rivers carved valleys and lakes shimmered. As Mars' magnetic field faded and its atmosphere thinned, most surface water vanished. Some escaped to space, some froze in polar caps, and some was trapped in minerals, where it remains today. But evaporation, freezing and rocks can't quite account for all the water that must have covered Mars in the distant past.

Calculations suggest the "missing" water is enough to cover the planet in an ocean at least 700 metres deep, and perhaps up to 900 metres deep. One hypothesis has been that the missing water seeped into the crust. Mars was heavily bombarded by meteorites during the Noachian period, which may have formed fractures that channelled water underground. Deep beneath the surface, warmer temperatures would keep the water in a liquid state — unlike the frozen layers nearer the surface.

In 2018, NASA's InSight lander touched down on Mars to listen to the planet's interior with a super-sensitive seismometer. By studying a particular kind of vibration called "shear waves", we found a significant underground anomaly: a layer between 5.4 and 8 kilometres down where these vibrations move more slowly. This "low-velocity layer" is most likely highly porous rock filled with liquid water, like a saturated sponge. Something like Earth's aquifers, where groundwater seeps into rock pores. We calculated the "aquifer layer" on Mars could hold enough water to cover the planet in a global ocean 520-780m deep.
InSight's seismometer captured vibrations between the crust of Mars and its lower layers from two meteorite impacts in 2021 and a Marsquake in 2022. "These signatures let us pinpoint boundaries where rock changes, revealing the water-soaked layer 5.4 to 8 kilometres deep."

It's an exciting possibility. "Purified, it could provide drinking water, oxygen, or fuel for rockets." And since microbes thrives on earth in deep rocks filled with water, "Could similar life, perhaps relics of ancient Martian ecosystems, persist in these reservoirs?"