A new study suggests Mercury may have shrunk about 30% more than scientists previously thought, losing as much as 14 miles in diameter as its interior cooled and contracted over billions of years. "That's significant for a planet barely 3,000 miles (4,900 kilometers) across," reports the Associated Press. From the report: Mercury's rough surface, continually reshaped by debris hurled from impact craters, may have hidden the true extent of the loss, according to the researchers whose findings appear in the journal Geophysical Research Letters. The news comes one week after a pair of European and Japanese spacecraft shed its cruising platform and advanced toward Mercury. Known as BepiColombo, the linked craft are expected to enter orbit around Mercury in November before splitting up for a fuller survey. BepiColombo's laser instrument should confirm how much Mercury is withering as a result of internal cooling, said Gaku Nishiyama, the study's lead author who is taking part in the space mission. The shrinkage could be even more than his team is estimating based on measurements from NASA's Messenger spacecraft in the 2010s. Only one other spacecraft has ever visited Mercury, NASA's Mariner 10 in the 1970s.

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alternative_right shares a report from ScienceDaily: A new analysis of more than 1,700 supernovae is questioning whether the universe is really accelerating at all. After accounting for the ages of the stars that produce these explosions, researchers found signs that cosmic expansion may actually be slowing. They also argue that the apparent acceleration changes with direction, which would be difficult to explain with dark energy. Other cosmologists dispute the conclusion, setting up a major test for upcoming observatories. The analysis has been published in Monthly Notices of the Royal Astronomical Society. The conclusion is disputed, though. The report mentions a separate paper co-authored by Professor Maria Vincenzi, also at the University of Oxford, that "concludes that observations continue to support an accelerating universe."

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"No rocket had ever reached orbit from Western European soil — until today," reports Space.com. DW.com reports that a Spectrum space rocket from German company Isar Aerospace launched today from the Arctic Norwegian spaceport at Andoya: "Germany has spaceflight capabilities," said the country's Ministry for Research, Technology and Space on X, praising a "milestone that impressively demonstrates our country's innovative strength and technical expertise". This was the German company's second attempt to launch the Spectrum rocket into space. The first attempt, which took place 18 months ago, was unsuccessful. The Spectrum rocket is designed for small and medium-sized payloads. It carried five smal satellites and an in-flight technological experiment, the company said. According to Isar Aerospace, the launch was for "both the vehicle's qualification mission and its first flight carrying payload." The move is believed to bring Europe closer to being able to offer satellite flights from its own territory. Several countries voiced interest in the growing market of commercial space missions, including Britain and Sweden... Isar is also working on the development of a second launch site, located in Canada. The company said that while the US launched 198 rockets last year, Europe's tally was just eight. Isar's goal is to produce some 40 rockets a year. Although the rocket is not yet ready for mass production, Isar has already received orders through 2028. Today's launch webcast was produced in collaboration with NASASpaceflight, notes Space.com. And they note that Spectrum chief engineer Nikolaos Perakis says"This is just the beginning... I'm really looking forward to the next steps." Reuters quotes this statemnt from Norway's minister of industry and commerce, Cecilie Myrseth. "The fact that we can now launch satellites from Andoeya strengthens Norwegian and European security in the turbulent times we live in."

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New submitter greytree shares a report from Brown University: LUX-ZEPLIN, an experiment co-led by Brown University faculty and students, observed a particle interaction that could be interpreted as a signal from WIMPs, a dark matter candidate -- but researchers need more data to confirm. [...] The result does not yet meet the statistical threshold required to claim a discovery, but it is the most compelling hint of dark matter reported by the experiment to date. "We're very intrigued to see this event in the data, in the region where we expect dark matter to show up, and the competing backgrounds are very low," said Rick Gaitskell, a professor of physics at Brown University and the spokesperson for LZ. "With only one event, we don't want to get ahead of ourselves. We are not claiming to have seen dark matter. But we have seen something interesting that we want to share with the scientific community for their input." [...] If the anomalous event was caused by dark matter, the WIMP that generated it would likely have a mass of at least 200 GeV/c2 (gigaelectronvolts), or more than 200 times the mass of a proton. The LZ results have not reached "5-sigma" significance, the statistical threshold in physics that an event must reach to be considered a discovery. The new analysis is 2.6 sigma, meaning there is approximately a 0.5% chance that the event could be explained by known backgrounds. With additional data, researchers can test whether the finding continues to grow in significance or fades away. LZ has already accumulated the world's largest dark matter dataset and will continue to accrue WIMP search data at SURF, substantially improving their search statistics. JiJi Fan, an associate professor of physics at Brown not involved in the LZ experimental research but whose theoretical work is cited in the new LZ paper, said the new findings were "very intriguing." While the event recorded by LZ could not have been the simplest type of WIMP interaction, there are other types of possible interactions that could explain it, she said. Had a WIMP interacted in the simplest way at the high energy associated with this recent event, the detector would have recorded many recoil events at lower energies following the initial event. LZ recorded a single event, however, which requires an expanded theoretical explanation. "There are well-motivated theoretical extensions, including inelastic scattering and momentum-dependent elastic scattering, that could potentially account for this single event," Fan said. "This also sets up a target for on-going dark matter hunting, not only at direct detection experiments such as LZ but also at other complementary experimental frontiers." The results were presented in a scientific talk at the 2026 TeV Particle Astrophysics conference in Japan on Tuesday, Sept. 1. A paper detailing the finding can be found here (PDF).

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SpaceX is significantly reducing Falcon 9 launches from Florida this year, ending the Space Coast's decade-long run as the world's busiest spaceport as more missions shift to Vandenberg Space Force Base in California. The slowdown is expected to continue until Starship begins flying regularly from Florida. Longtime Slashdot reader schwit1 shares a report from Ars Technica: A Falcon 9 launch early Tuesday was the last planned Starlink mission from Cape Canaveral until SpaceX begins flying Starship missions from Florida, according to Kiko Dontchev, the company's vice president of launch. For at least the rest of the year, and maybe longer, this means the launch rate at the Florida spaceport will drop from eight or nine per month to perhaps two per month. It wasn't long ago when two launches per month was the norm, an indication of just how quickly SpaceX's launch cadence has grown. Cape Canaveral and Kennedy Space Center sit on adjoining property and share the same range on Florida's east coast, so it is worth considering them a single spaceport. The last time the Florida spaceport did not lead the world in space launches was in 2015. "From here on, Starlink missions out of Florida will fly on Starship," Dontchev wrote on X. "The West Coast team will continue regularly launching Starlink from Vandenberg." "Yep, that'll be louder -- but everybody knows the real action will be in Louisiana, starting in 2029 or so," writes schwit1. SpaceX on Tuesday announced plans to spend up to $100 billion building a new Starship launch facility in Vermilion Parish, Louisiana, which the state says could eventually "support thousands of launches annually." Further reading: Musk's other unstated reasons for shutting down Falcon 9 in Florida (Behind The Black)

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SpaceX plans to spend up to $100 billion building a new Starship launch facility in Vermilion Parish, Louisiana, which the state says could eventually "support thousands of launches annually." CNBC reports: Once built, Starbase, LA will serve as the main launch facility for Starship, SpaceX's in-development rocket that's the largest ever built and designed to be fully reusable. Musk has aspirations to massively expand SpaceX's Starlink satellite network, to launch orbital data centers and to someday colonize Mars. Those ambitions, and justification for SpaceX's nearly $2 trillion market cap, hinge on the success of Starship. SpaceX said, in a video posted to its website on Tuesday, that the search for a site to build launch pads and have access to ample fuel for its operations took about seven years. Musk said in the video that the company would bring "probably 10,000 really exciting jobs" to Louisiana with the spaceport. A fact sheet posted online by the state of Louisiana said SpaceX is expected to generate an estimated "3,000 direct new jobs over the next 10 years" in the state, and "8,100 indirect new jobs." SpaceX said it would work on a "historic coastal restoration" in Louisiana, in partnership with the state to "bring the marsh back" and ensure the wetlands around its new facility will have "storm protection."

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