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'How We Sharpened the James Webb Telescope's Vision From a Million Kilometers Away'

Slashdot - Sat, 2025-10-18 16:34
The James Webb Space Telescope gets its highest resolution with the aperture masking interferometer (or AMI), "a tiny piece of precisely machined metal that slots into one of the telescope's cameras," according to a new article by Benjamin Pope, an associated math professor at Macquarie University. "We can finally present its first successful observations of stars, planets, moons and even black hole jets." [AMI] was put on Webb to diagnose and measure any blur in its images. Even nanometres of distortion in Webb's 18 hexagonal primary mirrors and many internal surfaces will blur the images enough to hinder the study of planets or black holes, where sensitivity and resolution are key. AMI filters the light with a carefully structured pattern of holes in a simple metal plate, to make it much easier to tell if there are any optical misalignments. We wanted to use this mode to observe the birth places of planets, as well as material being sucked into black holes. But before any of this, AMI showed Webb wasn't working entirely as hoped. At very fine resolution — at the level of individual pixels — all the images were slightly blurry due to an electronic effect: brighter pixels leaking into their darker neighbours. This is not a mistake or flaw, but a fundamental feature of infrared cameras that turned out to be unexpectedly serious for Webb. This was a dealbreaker for seeing distant planets many thousands of times fainter than their stars a few pixels away: my colleagues quickly showed that its limits were more than ten times worse than hoped. So, we set out to correct it... We built a computer model to simulate AMI's optical physics, with flexibility about the shapes of the mirrors and apertures and about the colours of the stars. We connected this to a machine learning model to represent the electronics with an "effective detector model" — where we only care about how well it can reproduce the data, not about why. After training and validation on some test stars, this setup allowed us to calculate and undo the blur in other data, restoring AMI to full function. It doesn't change what Webb does in space, but rather corrects the data during processing. It worked beautifully — the star HD 206893 hosts a faint planet and the reddest-known brown dwarf (an object between a star and a planet). They were known but out of reach with Webb before applying this correction. Now, both little dots popped out clearly in our new maps of the system... With the new correction, we brought Jupiter's moon Io into focus, clearly tracking its volcanoes as it rotates over an hour-long timelapse. "This correction has opened the door to using AMI to prospect for unknown planets at previously impossible resolutions and sensitivities..." the article points out. "Our results on painstakingly testing and enhancing AMI are now released on the open-access archive arXiv in a pair of papers." Thanks to long-time Slashdot reader schwit1 for sharing the article.

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Categories: Linux fréttir

Are Parts of the World Retreating on Electric Vehicles?

Slashdot - Sat, 2025-10-18 15:34
Canada's Prime Minister "paused an electric-vehicle sales mandate that was set to take effect next year," reports the Wall Street Journal, which argues a kind of retreat from electric-vehicle ambitions "is spreading around the globe." Even the U.K.'s Prime Minister "has allowed for a more flexible timetable to hit the country's EV targets." And demand is expected to drop in the U.S., where global consulting firm AlixPartners now predicts EVs will make up 18% of new-vehicle sales by 2030 — just half of what they'd predicted two years ago: j U.S. automaker GM will take a $1.6 billion charge "because of sinking EV sales," reports the Wall Street Journal, "a shift it blamed on recent moves by the U.S. government to end EV subsidies and regulatory mandates... That might just be the beginning of a financial reckoning from automakers that poured billions into new electric models — from sports cars and sedans to big pickups and sport-utility vehicles — to try to get ready for the government-backed EV mandates. Automakers have been saying that consumers aren't adopting EVs as quickly as expected, and government efforts to proliferate the technology are hammering their bottom lines. GM, in announcing its charge, said it is reassessing EV capacity and warned that more losses are possible...Carmakers argue the EV business model is an unprofitable proposition given still-high battery costs, spotty car-charging networks and dwindling government subsidies. Incentive programs have ended or have been pared back across Europe and in the U.S. and Canada. Volkswagen, burdened with massive electrification costs, helped spur the reckoning in Europe when it said it would cut 35,000 jobs as part of a deal with its union. The move sent shock waves through the region's political establishment. Weeks later, the EU launched a "strategic dialogue" with the automotive industry that led to a more flexible timetable for automakers to meet its emissions rules for 2025.

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Categories: Linux fréttir

Reddit Mod Warns 'Do Not Trust' AI-Powered 'Reddit Answers' After It Posts Dangerous Health Advice

Slashdot - Sat, 2025-10-18 14:34
In Reddit's "Family Medicine" subreddit, a moderator noticed earlier this week that the AI-powered "Reddit Answers" was automatically responding to posters, typically with "something related to what was posted." Unfortunately, that moderator says, Reddit Answers "has been spreading grossly dangerous misinformation."And yet Reddit's moderators "cannot disable this feature." Elsewhere a healthcare worker described what happened when they tested Reddit Answers: I made a post in r/familymedicine and a link appeared below it with information on treating chronic pain. The first post it cited urged people to stop their prescribed medications and take high-dose kratom which is an illegal (in some states) and unregulated substance. I absolutely do not endorse this... I also asked about the medical indications for heroin. One answer warned about addiction and linked to crisis and recovery resources. The other connects to a post where someone claims heroin saved their life and controls their chronic pain. The post was encouraging people to stop prescribed medications and use heroin instead. Heroin is a schedule I drug in the US which means there are no acceptable uses. It's incredibly addictive and dangerous. It is responsible for the loss of so many lives... The AI-generated answers could easily be mistaken as information endorsed by the sub it appears in. r/familymedicine absolutely does not endorse using heroin to treat chronic pain. This feature needs to be disabled in medical and mental health subs, or allow moderators of these subreddits to opt out. Better filters are also needed when users ask Reddit Answers health related questions. If this continues there will be adverse outcomes. People will be harmed. This needs to change. Two days ago an official Reddit "Admin" posted that "We've made some changes to where Answers appears based on this feedback," adding that beyond that Reddit "will continue to tweak based on what we're seeing and hearing." But the "Family Medicine" subreddit still has a top-of-page announcement warning every user there... "We do NOT and CANNOT endorse Reddit Answers at this time and urge every user of this sub to disregard anything it says."

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Categories: Linux fréttir

Email Bombs Exploit Lax Authentication In Zendesk

Slashdot - Sat, 2025-10-18 13:00
Cybercriminals are exploiting weak email authentication settings in Zendesk, using the platform's customer support systems to bombard targets with thousands of spam and harassing messages that appear to come from legitimate companies like The Washington Post, Discord, and NordVPN. KrebsOnSecurity reports: Zendesk is an automated help desk service designed to make it simple for people to contact companies for customer support issues. Earlier this week, KrebsOnSecurity started receiving thousands of ticket creation notification messages through Zendesk in rapid succession, each bearing the name of different Zendesk customers, such as CapCom, CompTIA, Discord, GMAC, NordVPN, The Washington Post, and Tinder. The abusive missives sent via Zendesk's platform can include any subject line chosen by the abusers. In my case, the messages variously warned about a supposed law enforcement investigation involving KrebsOnSecurity.com, or else contained personal insults. Moreover, the automated messages that are sent out from this type of abuse all come from customer domain names -- not from Zendesk. [...] In all of the cases above, the messaging abuse would not have been possible if Zendesk customers validated support request email addresses prior to sending responses. Failing to do so may make it easier for Zendesk clients to handle customer support requests, but it also allows ne'er-do-wells to sully the sender's brand in service of disruptive and malicious email floods. "We recognize that our systems were leveraged against you in a distributed, many-against-one manner," said Carolyn Camoens, communications director at Zendesk. "We are actively investigating additional preventive measures. We are also advising customers experiencing this type of activity to follow our general security best practices and configure an authenticated ticket creation workflow."

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Categories: Linux fréttir

Ruby Central tries to make peace after 'hostile takeover'

TheRegister - Sat, 2025-10-18 11:15
Taps Ruby core to oversee RubyGems, Bundler

Ruby Central, the non-profit that recently seized some Ruby open source tools from maintainers, is transferring the repository ownership of RubyGems and Bundler to the Ruby core team. The move appears to be an attempt to mollify the Ruby community following a divisive power grab, but it does not restore the control of those tools to the maintainers who previously oversaw them.…

Categories: Linux fréttir

Apple, Samsung Report Underwhelming Sales of Their New Thin Smartphones

Slashdot - Sat, 2025-10-18 10:00
In two separate reports, Apple and Samsung are said to report underwhelming sales of their new ultra-thin smartphones. According to The Elec, Apple plans to cut production of the iPhone Air while Samsung has canceled its planned Galaxy S26 Edge smartphone after disappointing sales of the Galaxy S25 Edge, Korea's NewsPim claims. MacRumors reports: Samsung apparently halted work on the Galaxy S26 Edge this week, informing employees internally that the product line would be discontinued. Internal discussions in September shifted priorities toward the more conventional "Plus" form factor after confirming that consumer demand for ultra-slim flagships was weaker than expected. [...] Samsung will apparently instead add a Galaxy S26 Plus model to its 2026 lineup, reverting to the company's traditional three-tier structure of base, Plus, and Ultra variants. Despite the cancellation, development of the Galaxy S26 Edge was already complete. Development of the S26 Plus is expected to begin before the end of the third quarter of 2025. The atmosphere inside the company is said to be "chaotic" and "embarrassed" following the sudden lineup revision. Samsung reportedly plans to sell through existing inventory of the Galaxy S25 Edge and cease further production once stock is depleted. As for Apple's iPhone Air, here's what MacRumors is reporting: The Japanese investment banking and securities firm claims that the iPhone 17 Pro and iPhone 17 Pro Max are seeing higher sales than their predecessors during the same period last year, while the standard iPhone 17 is a major success, performing significantly better than the iPhone 16. The iPhone Air is apparently the outlier; Apple plans to reduce production by one million units this year. Meanwhile, Apple plans to increase production of all other models by two million units. The overall production forecast of the iPhone 17 series this year has also been increased from 88 million units to 94 million units for the start of 2026.

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Categories: Linux fréttir

A Classified Network of SpaceX Satellites Is Emitting a Mysterious Signal

Slashdot - Sat, 2025-10-18 07:00
A network of classified Starshield satellites built by SpaceX for the U.S. government is transmitting signals on radio frequencies reserved for Earth-to-space commands. According to NPR, it may violate international standards. From the report: Satellites associated with the Starshield satellite network appear to be transmitting to the Earth's surface on frequencies normally used for doing the exact opposite: sending commands from Earth to satellites in space. The use of those frequencies to "downlink" data runs counter to standards set by the International Telecommunication Union, a United Nations agency that seeks to coordinate the use of radio spectrum globally. Starshield's unusual transmissions have the potential to interfere with other scientific and commercial satellites, warns Scott Tilley, an amateur satellite tracker in Canada who first spotted the signals. "Nearby satellites could receive radio-frequency interference and could perhaps not respond properly to commands -- or ignore commands -- from Earth," he told NPR. Outside experts agree there's the potential for radio interference. "I think it is definitely happening," said Kevin Gifford, a computer science professor at the University of Colorado, Boulder who specializes in radio interference from spacecraft. But he said the issue of whether the interference is truly disruptive remains unresolved. [...] Tilley says he's detected signals from 170 of the Starshield satellites so far. All appear in the 2025-2110 MHz range, though the precise frequencies of the signals move around.

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Categories: Linux fréttir

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