They haven't built a spacecraft for travelling to our nearest star system. But "Engineers have designed a spacecraft that could take up to 2,400 people on a one-way trip to Alpha Centauri," reports LiveScience: The craft, called Chrysalis, could make the 25 trillion mile (40 trillion kilometer) journey in around 400 years, the engineers say in their project brief, meaning many of its potential passengers would only know life on the craft. Chrysalis is designed to house several generations of people until it enters the star system, where it could shuttle them to the surface of the planet Proxima Centuri b — an Earth-size exoplanet that is thought to be potentially habitable.

The project won first place in the Project Hyperion Design Competition, a challenge that requires teams to design hypothetical multigenerational ships for interstellar travel.

Before boarding the ship, the Chrysalis project would require initial generations of ship inhabitants to live in and adapt to an isolated environment in Antarctica for 70 to 80 years to ensure psychological wellbeing. The ship could theoretically be constructed in 20 to 25 years and retains gravity through constant rotation. The vessel, which would measure 36 miles (58 km) in length, would be constructed like a Russian nesting doll, with several layers encompassing each other around a central core. The layers include communal spaces, farms, gardens, homes, warehouses and other shared facilities, each powered by nuclear fusion reactors....

This plan is purely hypothetical, as some of the required technology, like commercial nuclear fusion reactors, don't yet exist.
Thanks to long-time Slashdot reader fahrbot-bot for submitting the article — and for sharing this observation...

"My first thought was that someone read Arthur C. Clarke's book, Rendezvous with Rama and used it as a model design!"

NASA's Crew-10 mission has departed the International Space Station after 146 days, with astronauts Nichole Ayers, Anne McClain, Takuya Onishi, and Kirill Peskov set to splash down off California's coast on Saturday morning. You can watch a recording of the SpaceX Crew-10 undocking and departure on X. Reuters reports: The four-person crew launched to the ISS on March 14 in a routine mission that replaced the Crew-9 crew, which included NASA astronauts Butch Wilmore and Suni Williams, the astronaut pair left on the station by Boeing's Starliner capsule. Five months after the Starliner mission's conclusion, Wilmore this week retired from NASA after a 25-year career in which he flew four different spacecraft and logged a total of 464 days in space. Wilmore was a key technical adviser to Boeing's Starliner program along with Williams, who remains at the agency in its astronaut corps. [...] NASA said they are returning to Earth with "important and time-sensitive research" conducted in the microgravity environment of the ISS during the 146-day mission. The astronauts had over 200 science experiments on their to-do list.

Jim Lovell, the legendary NASA astronaut who commanded the Apollo 13 "successful failure" mission, has died at age 97. From a report: Lovell was already well-known among NASA astronauts, having flown to space on the Gemini 7, Gemini 12 and Apollo 8 missions, before he was selected to command Apollo 13, which would have marked the third successful crewed moon landing for NASA. But during the ill-fated mission -- which carried Lovell as well as astronauts John Swigert Jr. and Fred Haise Jr. on board -- an oxygen tank located on the crew's service module exploded when they were about 200,000 miles (322,000 kilometers) away from Earth.

Lovell delivered the news to mission control, saying "Houston, we've had a problem." With the damage effectively taking out the crew's power source and other life support supplies, the Apollo 13 crew had to abruptly abandon their trek to the lunar surface and use several engine burns to swing around the far side of the moon and put themselves on a course back toward Earth. The three-person crew made a high-stakes splashdown return in the South Pacific Ocean about three days after the tank explosion, marking the conclusion of what has come to be known as the "successful failure" of the Apollo missions. The ordeal was fictionalized in Ron Howard's 1995 film "Apollo 13." [...]

Lovell was the first astronaut to make four spaceflights, totaling more than 715 hours in space. He was part of NASA's second-ever astronaut class, selected in September 1962 and nicknamed the "New Nine." And joining the Apollo 13 crew after having first served on Apollo 8, which intentionally circumnavigated the moon but did not land on its surface, made Lovell the first human ever to see the moon up close for a second time. Further reading: Acting NASA Administrator Reflects on Legacy of Astronaut Jim Lovell (Source: NASA)

alternative_right quotes a report from The Register: Space fans looking to camp out in style have a chance to pick up an Airstream trailer that once served as the Convoy Command Vehicle for NASA's Space Shuttle operations at Edwards Air Force Base -- if they have a couple hundred thousand to spare, that is. "This is the NASA 025 Command Vehicle," current owner Jonathan Kitzen says of the once-silver, now paint-daubed and otherwise unassuming Airstream trailer. "NASA 025 was designed to land crewed missions at Edwards Air Force Base. [Airstream] informed me that this was, in their, words, 'the only NASA Airstream ever sold,' and the others [001-024] were all crushed or in museums. The sister crew vehicle (a 28-ft with one rear axle) is sitting at Kennedy museum [the Kennedy Space Center Visitor Complex]. All the rest are gone, except for this one."

Kitzen picked up the vehicle in 2022 up after spotting it on a government surplus auction site, where it had been listed with few details and at a very low starting price. As for how the rare vehicle ended up for sale in the first place, Kitzen says he was told it was a mistake. "Apparently there was some miscommunication when the vehicle was decommissioned," he claims in the sale listing. "It should have been offered to museums but the sales team did not know what it was. They were told it was just a 'NASA vehicle,' they did not know it had any special status or history. To the sellers they thought it was just a van that could have been for moving laundry around the base. It was an accidental (yet valid) sale.

"When I pulled up to Vandenberg Air Force Base after getting my NASA contractor badge I was greeted by the senior asset manager," Kitzen continues. "'We didn't know what we were selling!' were the first words out of her mouth. 'We didn't advertise it or offer it up to museums, the phone has exploded. Nobody told us what it was!'" [...] The listing on vehicle sale site Hemmings.com has an asking price of $199,000, though with no offers yet submitted. A listing on eBay with a $50,000 minimum bid and $290,000 buy-it-now price ended in May with no takers.

Ancient Slashdot reader Epeeist shares a report from The Guardian: The newest version of the maglev train is capable of traveling at 600km/h (about 370mph). However, the train's engineers have wrestled with the problem of the shock waves which occur as the train exits the mouth of a tunnel. When a high-speed train enters an enclosed space such as a tunnel, air in front is compressed, like in a piston. The resulting fluctuations in air pressure coalesce at the tunnel mouth, generating low-frequency shock waves. These are colloquially known as a "tunnel boom" -- a related, albeit different phenomenon to the "sonic boom" heard as aircraft pass the speed of sound. Tunnel booms pose serious challenges to operational safety, as the shock waves can disturb humans and animals nearby, as well as causing structural damage.

Now, however, researchers have discovered that placing innovative soundproofing buffers at tunnel mouths can reduce shock waves by up to 96%. This promises improvements in operational safety, noise pollution and passenger comfort, as well as safeguarding animals in the vicinity of future lines. [...] The porous structure of the new 100-meter long buffers, combined with porous coatings on the tunnel body, allow the trapped air to escape before the train reaches the tunnel mouth, suppressing the boom in the same way as a silencer fitted to a firearm.

Two fundamentally different methods for measuring the universe's expansion rate continue to produce incompatible results -- with direct observations of receding galaxies yielding approximately 73 kilometers per second per megaparsec and cosmic microwave background radiation analysis producing closer to 67 km/s/mpc.

The discrepancy, known as the Hubble tension, has strengthened annually for the past decadem, according to Duke University astronomer Dan Scolnic. The persistent disagreement prevents calculation of the universe's precise age or size. The Lambda-CDM model, which holds that dark energy and dark matter comprise 95% of the universe while visible matter constitutes just 5%, assumes dark energy's nature has remained constant since the Big Bang.

Some theorists propose dark energy's potency changes over time, while others suggest the Milky Way sits within a comparatively empty region of space. A June study using gravitational lensing of quasar light, bypassing traditional distance measurements, matched the higher value. New telescopes including the Vera Rubin Observatory and Nancy Grace Roman Space Telescope may provide additional data. Past improvements in measurement precision have only reinforced rather than resolved the tension.

The Trump administration has reportedly directed NASA to draw up plans to shut down its Orbiting Carbon Observatory satellite missions, which provide vital climate and agricultural data for scientists, oil and gas companies and farmers who need detailed information about carbon dioxide and crop health. As NPR reports, the satellites are "the only two federal satellite missions that were designed and built specifically to monitor planet-warming greenhouse gases." From the report: It is unclear why the Trump administration seeks to end the missions. The equipment in space is state of the art and is expected to function for many more years, according to scientists who worked on the missions. An official review by NASA in 2023 found that "the data are of exceptionally high quality" and recommended continuing the mission for at least three years.

Both missions, known as the Orbiting Carbon Observatories, measure carbon dioxide and plant growth around the globe. They use identical measurement devices, but one device is attached to a stand-alone satellite while the other is attached to the International Space Station. The standalone satellite would burn up in the atmosphere if NASA pursued plans to terminate the mission.

NASA employees who work on the two missions are making what the agency calls Phase F plans for both carbon-monitoring missions, according to David Crisp, a longtime NASA scientist who designed the instruments and managed the missions until he retired in 2022. Phase F plans lay out options for terminating NASA missions. The OCO missions would lose funding under the Trump Administration's budget proposal for Fiscal Year 2026, which begins Oct. 1 but has yet to pass. "Presidential budget proposals are wish lists that often bear little resemblance to final congressional budgets," notes NPR. "The Orbiting Carbon Observatory missions have already received funding from Congress through the end of the 2025 fiscal year, which ends Sept. 30."

"Draft budgets that Congress is currently considering for next year keep NASA funding basically flat. But it's not clear whether these specific missions will receive funding again, or if Congress will pass a budget before current funding expires on Sept. 30."

In a report published Monday, Cloudflare accused Perplexity of deploying undeclared web crawlers that masquerade as regular Chrome browsers to access content from websites that have explicitly blocked its official bots. Since then, Perplexity has publicly and loudly announced that Cloudflare's claims are baseless and technically flawed. "This controversy reveals that Cloudflare's systems are fundamentally inadequate for distinguishing between legitimate AI assistants and actual threats," says Perplexity in a blog post. "If you can't tell a helpful digital assistant from a malicious scraper, then you probably shouldn't be making decisions about what constitutes legitimate web traffic."

Perplexity continues: "Technical errors in Cloudflare's analysis aren't just embarrassing -- they're disqualifying. When you misattribute millions of requests, publish completely inaccurate technical diagrams, and demonstrate a fundamental misunderstanding of how modern AI assistants work, you've forfeited any claim to expertise in this space."

NASA's Lunar Trailblazer mission ended prematurely after losing contact with the satellite just one day post-launch, the agency announced today. Engadget reports: The NASA satellite was part of the IM-2 mission by Intuitive Machines, which took off from a SpaceX Falcon 9 rocket from Kennedy Space Center on February 26 at 7:16PM ET. The Lunar Trailblazer successfully separated from the rocket as planned about 48 minutes after launch. Operators in Pasadena, CA established communication with the satellite at 8:13PM ET, but two-way communication was lost the next day and the team was unable to recover the connection. From the limited data ground teams received before the satellite went dark, the craft's solar arrays were not correctly positioned toward the sun, which caused its batteries to drain. "While it was not the outcome we had hoped for, mission experiences like Lunar Trailblazer help us to learn and reduce the risk for future, low-cost small satellites to do innovative science as we prepare for a sustained human presence on the Moon," said Nicky Fox, associate administrator at NASA Headquarters' Science Mission Directorate. "Thank you to the Lunar Trailblazer team for their dedication in working on and learning from this mission through to the end."

An anonymous reader quotes a report from Politico: Transportation Secretary Sean Duffy will announce expedited plans this week to build a nuclear reactor on the moon, the first major action by the former Fox News host as the interim NASA administrator. NASA has discussed building a reactor on the lunar surface, but this would set a more definitive timeline -- according to documents obtained by POLITICO -- and come just as the agency faces a massive budget cut. [...] The reactor directive orders the agency to solicit industry proposals for a 100 kilowatt nuclear reactor to launch by 2030, a key consideration for astronauts' return to the lunar surface. NASA previously funded research into a 40 kilowatt reactor for use on the moon, with plans to have a reactor ready for launch by the early 2030s.

The first country to have a reactor could "declare a keep-out zone which would significantly inhibit the United States," the directive states, a sign of the agency's concern about a joint project China and Russia have launched. The directive also orders NASA to designate a leader for the effort and to get industry input within 60 days. The agency is seeking companies able to launch a reactor by 2030 since that's around the time China intends to land its first astronaut on the moon. The nuclear initiative means that NASA will continue to have a hand in nuclear development even after the Pentagon's recent cancellation of a joint program on nuclear-powered rocket engines. "While the budget did not prioritize nuclear propulsion, that wasn't because nuclear propulsion is seen as a non-worthy technology," the NASA official said.

"Jeff Bezos' Blue Origin launched a crypto billionaire and five other people to the final frontier on Sunday," reports Space.com: The mission — known as NS-34, because it was the 34th overall flight of Blue Origin's New Shepard vehicle — lifted off from the company's West Texas spaceport at 8:43 a.m. EDT (1243 GMT; 7:43 a.m. local time in West Texas).

The highest-profile NS-34 passenger was Justin Sun, a 34-year-old billionaire who founded the blockchain platform Tron. In June 2021, Sun won an auction for a seat aboard the first-ever crewed flight of New Shepard, plunking down $28 million. [Sun was unable to take that flight due to a scheduling conflict, but Blue Origin says "the proceeds from the $28 million bid benefitted 19 space-focused charities"...] The people flying with Sun on Sunday were Arvinder (Arvi) Singh Bahal, an Indian-born American real estate investor and adventurer; Turkish businessman and photographer Gökhan Erdem; Deborah Martorell, a journalist and meteorologist from Puerto Rico; Englishman Lionel Pitchford, who has run an orphanage in Nepal for three decades; and American entrepreneur James (J.D.) Russell... All six passengers were spaceflight rookies except Russell, who flew on Blue Origin's NS-28 mission in November 2024.

NS-34 was the 14th human spaceflight to date for New Shepard, which consists of a rocket topped by a crew capsule. Both of these elements are reusable; the rocket comes back to Earth for a vertical, powered touchdown like those performed by SpaceX's Falcon 9 rockets, and the capsule lands softly under parachutes. Each New Shepard flight lasts 10 to 12 minutes from liftoff to capsule touchdown.
"New Shepard has now flown 75 people into space," Blue Origin said in a statement, "including five people who have flown twice."

There's now an "influx" of startups fightging wildfires, reports the Washington Post.

"More than 100 new wildfire-related technologies have launched in the U.S. and around the world since 2023, according to Lori Moore-Merrell, who served as U.S. fire administrator during the Biden administration... Unmanned lookout poles that use AI to sense smoke have been erected in the West. Swarms of military-grade drones are increasingly used for wildfire detection and management. AI technology also tracks lightning strikes, which can ignite wildfires..." As America contends with what is already a punishing year of wildfires across massive swaths of the country, new, extremely precise satellite images beamed from space from the initiative FireSat. In March, a satellite outfitted with infrared sensors was launched more than 370 miles into space with the sole task of detecting and monitoring fires. With the ability to loop millions of miles around the planet each day, it found active fires and burn scars using bands of infrared light, demonstrating technology that the project's leaders and its early adopters said could be integral to filling technological gaps in the way they fight burns.

The satellite initiative was launched by a nonprofit coalition called Earth Fire Alliance (EFA). Its partners include Muon Space, which is developing the satellites; Google, which is using AI to help filter through the images; the Gordon and Betty Moore Foundation; and the Environmental Defense Fund. The goal is to have 50 satellites in orbit by 2030 to capture the entire world. At full capacity, the constellation is aiming to sweep the entire Earth every 20 minutes to detect small fires. By spring or summer of next year, it plans to launch three more satellites into space that will coordinate with agencies in states including California and Colorado to help them detect and fight fire.

After it began "peering into the distant universe" in 2022, NASA's James Webb Space Telescope "has discovered a rash of 'little red dots'," reports Science magazine. There's "hundreds of them, shining within the first billion years of the 13.8-billion-year-old universe, so small and red that they defied conventional explanation."

"Only in the past few months has a picture begun to emerge. The little red dots, astronomers say, may be an entirely new type of object: a colossal ball of bright, hot gas, larger than the Solar System, powered not by nuclear fusion, but by a black hole..." The objects, which some astronomers are calling "black hole stars," could be a missing link in the evolution of galaxies and help explain the rapid growth of supermassive black holes that lie at their hearts. "The big breakthrough of the past 6 months is actually the realization that we can throw out all these other models we've been playing with before," says astronomer Anna de Graaff of the Max Planck Institute for Astronomy... JWST couldn't resolve the dots into a recognizable shape, which meant they must have been tiny — less than 2% of the diameter of the Milky Way. "It was a mystery ... as to why they were so spatially compact," says Caitlin Casey of the University of Texas at Austin. An impossibly dense packing of stars would be needed to explain their brightness. "I was excited," Casey says...

For Mitch Begelman, a theoretical astrophysicist at the University of Colorado Boulder, the observations are a vindication. Earlier this month, he and a colleague posted a preprint on arXiv reviving a scenario for the formation of hypothetical "quasi-stars" that he and others had proposed 20 years ago. The first generation of stars, they calculated, could have grown to colossal size in the early universe, which was made up almost entirely of hydrogen, the raw material of stars. When a giant star ran out of fuel, they said, its core would have collapsed into a black hole, but the outer envelope of hydrogen was so dense it survived the blast, enclosing the newborn black hole. As the black hole chewed at its shroud of gas, the entire system glowed as a quasi-star larger than the Solar System. "That's what the quasi-star envelope is doing, it's force-feeding the black hole by pushing matter into it," Begelman says.

Given how common little red dots appear to be in the early universe, theorists are beginning to wonder whether this giant-ball-of-gas phase is an essential part of black hole growth and the evolution of galaxies. "We're probably looking at kind of a new phase of black hole growth that we didn't know about before," de Graaff says.
"If the red dots do turn out to be black hole stars, it will be precisely the sort of breakthrough expected from JWST — and the kind of discovery astronomers live for."

Thanks to Slashdot reader sciencehabit for sharing the news.

The vehicle "once led the Space Shuttle down the runway at Edwards Air Force Base," The Drive reported in 2022, noting it was won in an auction for $21,061 (beating 18 other bidders). "I just figured the NASA brand combined with Airsteam hip seemed like a can't lose combination," the buyer says now, in a listing for the vehicle on the on the automotive sales site Hemmings.com asking $199,000..

They're touting it as a priceless marketing/publicity prop — "a once in a lifetime opportunity" to own what was once an "onsite command center complete with communications and atmospheric monitoring... Imagine pulling into Burning Man driving this..." The seller points out it's the only custom-built "Airstream" trailer ever sold by NASA. (The others were crushed, except for one donated to the Kennedy museum.) But for this one "Apparently there was some miscommunication when the vehicle was decommissioned. It should have been offered to museums but the sales team did not know what it was.")

"Has only 8240 miles on it as driven from Ohio to California then around the Edwards base."

The seller apparently first tried listing it on eBay in May for $50,000. ("Reserve not met," says that listing page now. "Very well maintained, minor dings on exterior...")

Thanks to long-time Slashdot reader schwit1 for sharing the news.

An anonymous reader quotes a report from Ars Technica: Silicon Valley's AI talent war just reached a compensation milestone that makes even the most legendary scientific achievements of the past look financially modest. When Meta recently offered AI researcher Matt Deitke $250 million over four years (an average of $62.5 million per year)—with potentially $100 million in the first year alone -- it shattered every historical precedent for scientific and technical compensation we can find on record. [Meta CEO Mark Zuckerberg reportedly also offered an unnamed AI engineer $1 billion in compensation to be paid out over several years.] That includes salaries during the development of major scientific milestones of the 20th century. [...]

To put these salaries in a historical perspective: J. Robert Oppenheimer, who led the Manhattan Project that ended World War II, earned approximately $10,000 per year in 1943. Adjusted for inflation using the US Government's CPI Inflation Calculator, that's about $190,865 in today's dollars -- roughly what a senior software engineer makes today. The 24-year-old Deitke, who recently dropped out of a PhD program, will earn approximately 327 times what Oppenheimer made while developing the atomic bomb. [...] The Apollo program offers another striking comparison. Neil Armstrong, the first human to walk on the moon, earned about $27,000 annually -- roughly $244,639 in today's money. His crewmates Buzz Aldrin and Michael Collins made even less, earning the equivalent of $168,737 and $155,373, respectively, in today's dollars. Current NASA astronauts earn between $104,898 and $161,141 per year. Meta's AI researcher will make more in three days than Armstrong made in a year for taking "one giant leap for mankind." The report notes that the sums being offered to some of these AI researchers top even the most popular sports athletes. "The New York Times noted that Steph Curry's most recent four-year contract with the Golden State Warriors was $35 million less than Deitke's Meta deal (although soccer superstar Cristiano Ronaldo will make $275 million this year as the highest-paid professional athlete in the world)," reports Ars.

An anonymous reader quotes a report from The Guardian: A 515-mile (829km) lightning flash has set a new record as the longest ever identified. The World Meteorological Organization (WMO) confirmed the new world record for the flash registered on October 22, 2017, over the Great Plains in the US. It stretched from east Texas to near Kansas City, Missouri, roughly the distance between Paris and Venice. The previous record of 768km was also recorded in the Great Plains, a hotspot for severe thunderstorms, on April 29, 2020.

Since 2016, scientific advances in space-based mapping have allowed for lightning flashes to be measured over a broader space, allowing these long flashes to be recorded. This event was one of the first flashes to be documented using the National Oceanic and Atmospheric Administration's latest model of orbital satellite, known as a geostationary operational environmental satellite. [...] The advances in technology have also allowed for the recording of the greatest duration for a single lightning flash. The record is a flash that lasted 17.1 seconds during a thunderstorm over Uruguay and northern Argentina on June 18, 2020. The findings have been published in the journal Bulletin of the American Meteorological Society.

Australia's first domestically built rocket to attempt orbital launch crashed just 14 seconds after liftoff, though the company still declared the mission a success for igniting all engines and leaving the launch pad. The Associated Press reports: The rocket Eris, launched by Gilmour Space Technologies, was the first Australian-designed and manufactured orbital launch vehicle to lift off from the country and was designed to carry small satellites to orbit. It launched Wednesday morning local time in a test flight from a spaceport near the small town of Bowen in the north of Queensland state. In videos published by Australian news outlets, the 23-meter (75-foot) rocket appeared to clear the launch tower and hovered in the air before falling out of sight. Plumes of smoke were seen rising above the site. No injuries were reported. The company hailed the launch as a success in a statement posted to Facebook. A spokesperson said all four hybrid-propelled engines ignited and the maiden flight included 23 seconds of engine burn time and 14 seconds of flight. "Of course I would have liked more flight time but happy with this," wrote CEO Adam Gilmour on LinkedIn. Gilmour said in February that it was "almost unheard of" for a private rocket company to successfully launch to orbit on its first attempt.

"This is an important first step towards the giant leap of a future commercial space industry right here in our region," added Mayor Ry Collins of the local Whitsunday Regional Council.

India launched the $1.5 billion NISAR radar imaging satellite on Wednesday from the Satish Dhawan Space Centre, marking the first joint mission between NASA and the Indian Space Research Organisation. The satellite uses dual radar frequencies -- NASA's L-band and ISRO's S-band -- to detect Earth surface changes as small as one centimeter from its 747-kilometer orbit.

NISAR will map the entire planet every 12 days using a 240-kilometer-wide radar swath, providing data for climate monitoring and disaster response that will be freely available to users worldwide.

A new study analyzing distorted sound waves from the early universe suggests we may live in a massive cosmic void "with roughly 20% lower than the average density of matter," writes Indranil Banik in an article for The Conversation. "Not every physicist is convinced that this is the case. But our recent paper analyzing distorted sounds from the early universe, published in the Monthly Notices of the Royal Astronomical Society, strongly backs up the idea." Slashdot reader alternative_right shares an excerpt from the report: My colleagues and I previously argued that the Hubble tension might be due to our location within a large void. That's because the sparse amount of matter in the void would be gravitationally attracted to the more dense matter outside it, continuously flowing out of the void. In previous research, we showed that this flow would make it look like the local universe is expanding about 10% faster than expected. That would solve the Hubble tension. But we wanted more evidence. And we know a local void would slightly distort the relation between the BAO angular scale and the redshift due to the faster moving matter in the void and its gravitational effect on light from outside.

So in our new paper, Vasileios Kalaitzidis and I set out to test the predictions of the void model using BAO measurements collected over the last 20 years. We compared our results to models without a void under the same background expansion history. In the void model, the BAO ruler should look larger on the sky at any given redshift. And this excess should become even larger at low redshift (close distance), in line with the Hubble tension. The observations confirm this prediction. Our results suggest that a universe with a local void is about one hundred million times more likely than a cosmos without one, when using BAO measurements and assuming the universe expanded according to the standard model of cosmology informed by the CMB.

Our research shows that the ACDM model without any local void is in "3.8 sigma tension" with the BAO observations. This means the likelihood of a universe without a void fitting these data is equivalent to a fair coin landing heads 13 times in a row. By contrast, the chance of the BAO data looking the way they do in void models is equivalent to a fair coin landing heads just twice in a row. In short, these models fit the data quite well. In the future, it will be crucial to obtain more accurate BAO measurements at low redshift, where the BAO standard ruler looks larger on the sky -- even more so if we are in a void. The average expansion rate so far follows directly from the age of the universe, which we can estimate from the ages of old stars in the Milky Way. A local void would not affect the age of the universe, but some proposals do affect it. These and other probes will shed more light on the Hubble crisis in cosmology.

Measuring earth's position (or "geodesy") requires using telescopes that track radiation from distant black holes. Their signals "pass cleanly through the atmosphere and we can receive them during day and night and in all weather conditions," writes a senior scientist at the University of Tasmania.

But there's a problem... Radio waves are also used for communication on Earth — including things such as wifi and mobile phones... [A] few narrow lanes are reserved for radio astronomy. However, in previous decades the radio highway had relatively little traffic. Scientists commonly strayed from the radio astronomy lanes to receive the black hole signals. To reach the very high precision needed for modern technology, geodesy today relies on more than just the lanes exclusively reserved for astronomy.

In recent years, human-made electromagnetic pollution has vastly increased. When wifi and mobile phone services emerged, scientists reacted by moving to higher frequencies. However, they are running out of lanes. Six generations of mobile phone services (each occupying a new lane) are crowding the spectrum... Today, the multitude of signals are often too strong for geodetic observatories to see through them to the very weak signals emitted by black holes. This puts many satellite services at risk.

To keep working into the future — to maintain the services on which we all depend — geodesy needs some more lanes on the radio highway. When the spectrum is divided up via international treaties at world radio conferences, geodesists need a seat at the table. Other potential fixes might include radio quiet zones around our essential radio telescopes. Work is also underway with satellite providers to avoid pointing radio emissions directly at radio telescopes. Any solution has to be global. For our geodetic measurements, we link radio telescopes together from all over the world, allowing us to mimic a telescope the size of Earth. The radio spectrum is primarily regulated by each nation individually, making this a huge challenge.

But perhaps the first step is increasing awareness. If we want satellite navigation to work, our supermarkets to be stocked and our online money transfers arriving safely, we need to make sure we have a clear view of those black holes in distant galaxies — and that means clearing up the radio highway.