Five months after its liberation from the police state of Bashar al-Assad, Syria sometimes looks like a country in civil war. Sectarian clashes have turned into street battles with rockets and mortars. In the southern province of Suweida, local leaders have denounced the new Syrian government as a band of terrorists, and they fly the flag of a Druze statelet that flourished a century ago. The country's new president, Ahmed al-Sharaa, has tried repeatedly to reassure Syria's religious minorities, saying he wants peace and pluralism. He won some unexpected relief on the economic front yesterday, when President Donald Trump, who is visiting the Gulf states, agreed to drop all American sanctions on Syria. But he seems unable to remedy the structural flaws that have fed the violence of recent months. His fledgling state is too centralized, and too dependent on former jihadists he cannot control. In March, Sunni Islamist gangs massacred Alawites on the Syrian coast, in attacks that left well over 1,000 people dead. Alawite friends tell me they live in constant fear, as these gangs roam the streets and sometimes confiscate their houses at gunpoint under the dubious authority of a 'war-spoils committee.' Several have asked for my help in escaping a country that now seems alien to them....

China's Tianwen-2 asteroid sample return mission is set to launch this month, May 2025, en route to the asteroid Kamo'oalewa (2016 HO3). The country could join the United States and Japan, whose space agencies have both successfully retrieved a sample from an asteroid to study back on Earth. Several space missions have flown by asteroids before and gotten a peek at their compositions, but bringing a sample back to Earth is even more helpful for scientists. The most informative analyses require having physical samples to poke and prod, shine light at, run through CT scanners and examine under electron microscopes. These missions require detailed planning and specialized spacecraft, so to shed light on why agencies go through the trouble, we compiled four stories from The Conversation U.S.'s archive. These articles describe the ways asteroid sample return missions generate new scientific insights at every stage ' from the collection process, to the container's return to Earth, to laboratory analyses....

When you put your hand out the window of a moving car, you feel a force pushing against you called drag. This force opposes a moving vehicle, and it's part of the reason why your car naturally slows to a stop if you take your foot off the gas pedal. But drag doesn't just slow down cars. Aerospace engineers are working on using the drag force in space to develop more fuel-efficient spacecraft and missions, deorbit spacecraft without creating as much space junk, and even place probes in orbit around other planets. Space is not a complete vacuum ' at least not all of it. Earth's atmosphere gets thinner with altitude, but it has enough air to impart a force of drag on orbiting spacecraft, even up to about 620 miles (1,000 kilometers). As an aerospace engineering professor, I study how drag affects the movement of spacecraft in orbit. Aerobraking, as the name suggests, is a type of maneuver that uses the thin air in space to apply a drag force in the direction opposite to a spacecraft's motion, much like braking in a car....

Live and on-demand video constituted an estimated 66% of global internet traffic by volume in 2022, and the top 10 days for internet traffic in 2024 coincided with live streaming events such as the Jake Paul vs. Mike Tyson boxing match and coverage of the NFL. Streaming enables seamless, on-demand access to video content, from online gaming to short videos like TikToks, and longer content such as movies, podcasts and NFL games. The defining aspect of streaming is its on-demand nature. Consider the global reach of a Joe Rogan podcast episode or the live coverage of the SpaceX Crew Dragon spacecraft launch ' both examples demonstrate how streaming connects millions of viewers to real-time and on-demand content worldwide. When it comes to video content ' whether it's a live stream or a prerecorded video ' there are two major challenges to address. First, video data is massive in size, making it time-consuming to transmit from the source to devices such as TVs, computers, tablets and smartphones....