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From the moment Chuck Yeager broke the sound barrier for the first time in 1947, zipping from New York to Paris in less than three hours became every travelers dream. It’s a dream that shattered as soon as everyone realized supersonic flight was really annoying for people on the ground. Thats why NASA and Lockheed Martin created the X-59 Quesst, which was designed with an aerodynamic profile that would reduce the eardrum-breaking boom to a dull thump. NASA’s upcoming test flight was supposed to be the first silent supersonic flight in historythen January 28 happened. That’s when the startup company Boom Supersonic flew a supersonic flight over the Mojave Desert, in California, using a radically different approach that was theorized decades ago but only now has been possible thanks to new engines and computers. [Photo: Boom Supersonic] The company announced the milestone February 10. The testing of its Boomless Cruise technologyrecorded with a sophisticated microphone array by NASAshowed that its XB-1 demonstrator aircraft broke the sound barrier three times without generating a sonic boom that reached the ground. This is the first time a plane has achieved this. On our first flight, we expected to break the sound barrier without a sonic boomthat was our prediction, Blake Scholl, founder and CEO of Boom Supersonic, tells me. We broke the sound barrier three times: on the first flight, no boom; and on the second flight, three more times. Our forecast was no sonic boom, and that’s exactly what we had. Rather than redesigning the physical airframe of the airplane to redirect air and reduce the supersonic shock volumelike the X-59the company bet on taking advantage of using a physical phenomenon called Mach cutoff, using powerful computers and software to carefully change the airplane’s speed and altitude depending on the weather around it. [Photo: Boom Supersonic] Mach cutoff is a phenomenon where a sonic boom, instead of traveling directly to the ground, bends upwards and dissipates into the atmosphere. There is a boom that comes off the airplane, but it makes a kind of U-turn in the sky, Scholl explains. And as long as the boom is coming off the airplane at the right angle and its high enough, you can think of it as the bottom of the U never touches the ground. And as long as the bottom of the U never touches the ground, there’s no audible boom. This phenomenon occurs because the sonic boom refracts upward due to temperature and wind gradients affecting the local speed of sound, just as how a pen appears to bend when passing through a glass of water because the difference in the density of water and air affects how light propagates. The NASA X-59 [Image: Lockheed Martin] Unlike the X-59s low-boom approach, Boomless Cruise aims to entirely eliminate the boom at ground level. The X-59 is designed to manage the shockwaves through its airframe design, aiming for a gentle thump. The way the engine is placed, and the fact that theres no cockpit breaking the flow of air, its Pinocchio nose reduces the sonic boom. Scholl says the approach works, but there’s still a boom. With Boomless Cruise, there literally is none. During its first supersonic flight, XB-1 reached a top speed of Mach 1.12, demonstrating that the theory works. The data collected during XB-1’s supersonic runs allowed Boom to validate their sonic boom models and refine the algorithms that predict the operation within Mach cutoff. The successful flight test validated that this works. [Photo: Boom Supersonic] What were doing is well-known physics thats been around for a long time, Scholl says. The key to making it a reality now lies in advanced engine technology and sophisticated computing capabilities, which were unavailable in the past. The Concorde could have done it, but its engines werent powerful enough and they required afterburning to reach supersonic speed. The kind of computing power thats needed to do what the XB-1 did during its two flight tests also didnt exist. So, fast-forward 50 years, computers, weve got great weather data, and weve got engines that are powerful enough to fly supersonic without afterburners. [Photo: Boom Supersonic] The future of supersonic flight After validating Boomless Cruise technology, the company is planning to build its supersonic airliner. It will utilize the Symphony engine, which is specifically designed for enhanced transonic performance, to enable Boomless Cruise for commercial flights. Symphony’s enhanced transonic thrust will allow its commercial airliner, called Overture, to surpass the sound barrier at altitudes exceeding 30,000 feet. This altitude is sufficient for Mach cutoff physics to function. According to Boom Supersonic, Overture will use the company’s secret sauce: an advanced autopilot system that continuously optimizes speed for the Boomless Cruise based on real-time atmospheric conditions. This is what allows it to avoid the sonic boom. This dynamic adjustment is essential because weather conditions, particularly temperature and wind, significantly affect the speed of sound and the behavior of the sonic boom. [Photo: Boom Supersonic] If all goes as well with the demonstrator, the only major hurdle will not be technical but legal. Just as NASA is trying to do with its Quesst program, the company will need to convince lawmakers to allow for supersonic flight from coast to coast, over the continental United States. Hes convinced it will happen. It’s a very simple regulatory change. We should have a noise limit, not a speed limit, he tells me. Boom Supersonic also notes on its site that Overture is not designed as a low-boom aircraft, and [they] do not expect to certify it for unrestricted supersonic flight over land. This means that, over sea, the airplane’s speed will be unrestricted, reaching Mach 1.7. There will be no speed limit because the sonic boom doesn’t matter over the ocean, and flying from Paris to New York will be twice as fast, taking only about 3.5 hours versus the current 7 hours. Over land, however, the future aircraft’s speed will be restricted to Mach 1.3 to avoid the booms, Scholl says: Sometimes, as low as 1.05 and sometimes as high as 1.3. Usually, itll be between 1.1 [and] 1.2. That’s 50% faster than current commercial planes, which will get you from New York to Los Angeles in around three hours rather than six. Whatever happens with regulations, with this successful display, Boom Supersonic has demonstrated that it can be done. We will need to wait and see if it reaches the point in which we will enjoy quiet, affordable, and sustainable supersonic travel. And perhaps restart the era in commercial aviation that the Concorde brought to the world.
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The ceasefire agreed between Israel and Hamas makes provisions for the passage of food and humanitarian aid into Gaza. This support is much needed given that Gazas agricultural system has been severely damaged over the course of the war. Over the past 17 months we have analysed satellite images across the Gaza Strip to quantify the scale of agricultural destruction across the region. Our newly published research reveals not only the widespread extent of this destruction but also the potentially unprecedented pace at which it occurred. Our work covers the period until September 2024 but further data through to January 2025 is also available. Before the war, tomatoes, peppers, cucumbers and strawberries were grown in open fields and greenhouses, and olive and citrus trees lined rows across the Gazan landscape. The trees in particular are an important cultural heritage in the region, and agriculture was a vital part of Gazas economy. About half of the food eaten there was produced in the territory itself, and food made up a similar portion of its exports. By December 2023, only two months into the war, there were official warnings that the entire population of Gaza, more than 2 million people, was facing high levels of acute food insecurity. While that assessment was based on interviews and survey data, the level of agricultural damage across the whole landscape remained out of view. Tree crop damage by month from October 2023 to September 2024. The months in which damage first occurred are in blue and purple, while undamaged tree crops are shown in green. [Image: Yin et al (2025)] Most olive and citrus trees are gone To address this problem, we mapped the damage to tree crops mostly olive and citrus trees in Gaza each month over the course of the war up until September 2024. Together with our colleagues Dimah Habash and Mazin Qumsiyeh, we did this using very high-resolution satellite imagery, detailed enough to focus on individual trees. We first visually identified tree crops with and without damage to train our computer program, or model, so it knew what to look for. We then ran the model on all the satellite data. We also looked over a sample of results ourselves to confirm it was accurate. Our results showed that between 64% and 70% of all tree crop fields in Gaza had been damaged. That can either mean a few trees being destroyed, the whole field of trees completely removed, or anything in between. Most damage took place during the first few months of the war in autumn 2023. Exactly who destroyed these trees and why is beyond the scope of our research or expertise. Greenhouses and the date of initial damage between October 2023 and September 2024. [Image: Yin et al (2025)] In some areas, every greenhouse is gone As greenhouses look very different in satellite images, we used a separate method to map damage to them. We found over 4,000 had been damaged by September 2024, which is more than half of the total we had identified before the start of the war. In the south of the territory, where most greenhouses were found, the destruction was fairly steady from December 2023 onwards. But in north Gaza and Gaza City, the two most northerly of the territorys five governorates, most of the damage had already taken place by November and December 2023. By the end of our study period, all 578 greenhouses there had been destroyed. North Gaza and Gaza City have also seen the most damage to tree crop fields. By September 2024, over 90% of all tree crops in Gaza City had been destroyed, and 73% had been lost in north Gaza. In the three southern governorates, Khan Younis, Deir al-Balah and Rafah, around 50% of all tree crops had been destroyed. Agricultural damage is common in armed conflict, and has been documented with satellite analysis in Ukraine since the 2022 Russian invasion, in Syria and Iraq during the ISIS occupation in 2015, and in the Caucasus during the Chechen wars in the 1990s and 2000s. Satellite images show destruction of trees (top) and greenhouses (bottom) in north Gaza. [Image: Yin et al (2025)] The exact impact can differ from conflict to conflict. War may directly damage lands, as we have seen in Gaza, or it may lead to more fallow reas as infrastructure is damaged and farmers are forced to flee. A conflict also increases the need for local agricultural production, especially when food imports are restricted. Our assessment shows a very high rate of direct and extensive damage to Gazas agricultural system, both compared to previous conflict escalations there in 2014 and 2021, and in other conflict settings. For example, during the July-August war in 2014, around 1,200 greenhouses were damaged in Gaza. This time round at least three times as many have been damaged. Agricultural attacks are unlawful Attacks on agricultural lands are prohibited under international law. The Rome Statute of the International Criminal Court from 1998 defines the intentional use of starvation of civilians through depriving them of objects indispensable to their survival as a war crime. The Geneva conventions further define such indispensable objects as foodstuffs, agricultural areas for the production offoodstuffs, crops, livestock, drinking water installations and supplies and irrigation works. Our study provides transparent statistics on the extent and timing of damage to Gazas agricultural system. As well as documenting the impacts of the war, we hope it can help the massive rebuilding efforts that will be required. Restoring Gazas agricultural system goes beyond clearing debris and rubble, and rebuilding greenhouses. The soils need to be cleaned from possible contamination. Sewage and irrigation infrastructure need to be rebuilt. Such efforts may take a generation or more to complete. After all, olive and citrus trees can take five or more years to become productive, and 15 years to reach full maturity. After previous attacks on Gaza the trees were mostly replanted, and perhaps the same will happen again this time. But its for good reason they say that only people with hope for the future plant trees. Lina Eklund is an associate senior lecturer at Lund University. He Yin is an assistant professor of geography at Kent State University. Jamon Van Den Hoek is an associate professor of geography at Oregon State University. This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Hate speech on X dramatically increased during the several months that Elon Musk served as CEO when compared to the prior months, according to a new study. The analysis, published Wednesday, showed that hate speech spiked on the platform shortly before Musk purchased X (then called Twitter), and continued through May 2023. Researchers found that the weekly rate of hate speech was up about 50% over the months prior to Musk’s purchase. The study noted an increase in use of homophobic, transphobic, and racist slurs. The researchers also found a spike in “likes” of hate posts, which they said indicate increased engagement. The findings run contrary to Musk’s claims that hate speech impressions on the platform were sloping downward. (X did not respond to Fast Company‘s request for comment.) To be sure, the researchers said they could not set firm conclusions on a cause-effect relationship between Musk’s acquisition of X and the findings. Still, they argued for stronger moderation and more research. “Overall, these results highlight a need for increased moderation to combat hate and inauthentic accounts on X,” the researchers wrote. Once Musk took over the social media company, he quickly loosened restrictions on what can be said or shared on the platform. The study’s release coincides with the slow return of many high-profile advertisers to X. Several brands, including Comcast, Apple, IBM, Disney, and Warner Bros., pulled their ad spend from the platform soon after Musk’s takeover, because ads began to appear next to hate speech and other offensive content. But now Musk is one of the top officials in President Trump’s administration, and some may want to bolster their relationships with Musk. Apple is reportedly considering returning to the platform. Comcast, IBM, Disney, and Warner Bros. have all resumed ad spend, according to The Wall Street Journal. Still, ad buyers have said that brands that return to X are spending much less than they were before Musk acquired the company. (Amazon is reportedly upping its ad spend.)
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