Latest news with #Caltech
Yahoo
a day ago
- Science
- Yahoo
‘Third wheel' or matchmaker? Distant star may help forge explosive white dwarf duos
Some love stories are written in the stars, quite literally. A new Caltech-led study has found that some explosive star duos may have formed thanks to a third, more distant star. These dramatic systems often involve a white dwarf, the dense, burnt-out core left behind when a star like our Sun dies. In close stellar pairs, white dwarfs can pull material from their companion star, triggering powerful outbursts known as novae. Long thought to result from just two stars spiraling together through a shared envelope of gas, these volatile systems, known as cataclysmic variables (CVs), might actually owe their origins to a cosmic third wheel that nudges the inner pair into a tighter orbit. "Our results are revealing another formation channel for CVs," says Kareem El-Badry, assistant professor of astronomy at Caltech and the study's co-author. "Sometimes, a lurking third star is key," he says. To explore this possibility, the researchers turned to data from the European Space Agency's Gaia mission, which has provided precise measurements of stars across the galaxy. They identified 50 CVs in so-called hierarchical triple-star systems, where two stars orbit closely while a third orbits much farther away. The team found that about 10 percent of known CVs fall into this category, a figure too high to be coincidental. To dig deeper, the team ran computer simulations of 2,000 hypothetical triple-star systems. These models showed that, in many cases, the gravity of the third star can stretch the orbit of the inner binary until the two stars swing close enough for tidal forces to take over, bringing them together without the need for the traditional gas-envelope phase. In fact, 20 percent of the simulated CVs formed entirely without this envelope process, while 60 percent showed the third star kickstarting the spiral-in that leads to a shared envelope. "The gravity of the third star causes the binary stars to have a super eccentric orbit, and this forces the companion star closer to the white dwarf. Tidal forces dissipate energy and shrink and circularize the orbit," said Cheyanne Shariat, A Caltech graduate student and lead author of the study. "The star doesn't have to spiral in through the common envelope," When the researchers scaled their simulations to reflect a realistic population of stars in our galaxy, they concluded that as many as 40 percent of all CVs may have formed in triple systems. The simulations also offered clues about which triple-star systems are more likely to produce cataclysmic variables. One important factor was distance. The systems that gave rise to CVs typically started with a wide separation, more than 100 astronomical units, between the inner stellar pair and the distant third star. An astronomical unit, or AU, is the average distance between the Earth and the Sun. Many of these third stars may now be too faint or too far away to detect, or may have been flung out of the system entirely. "For the past 50 years, people were using the spiral-in common-envelope evolution model to explain CV formation," El-Badry said. "Nobody had noticed before that this was largely happening in triples!" The findings have appeared in the journal Publications of the Astronomical Society of the Pacific.
New York Times
5 days ago
- Business
- New York Times
Caltech Agrees to Settle Lawsuit Accusing It of Misleading Students
The California Institute of Technology has agreed to settle a class-action lawsuit that accused it of misleading students who signed up for a 'boot camp' that carried Caltech's name but in practice had scant ties to the school, one of the world's richest universities. The settlement called for Caltech and an outside partner, Simplilearn, to change how they advertised the boot camp, adding new restrictions that threatened the program's allure. But on Monday, the day a court released documents that detailed the settlement's terms, Caltech said in an open letter it would cut ties with Simplilearn later this year. Nevertheless, the settlement, which still requires a judge's approval, may influence how other schools market similar offerings. Caltech is among hundreds of universities across the country, many of them looking for new sources of revenue, that have licensed their names to promote courses that were actually run by outside companies, with the university often playing only limited roles in hiring, instruction or curriculum development. Some universities earn several thousand dollars for each student who enrolls in a branded program; researchers estimate that those fees add up to hundreds of millions of dollars a year across the higher education industry. Want all of The Times? Subscribe.
Yahoo
6 days ago
- Science
- Yahoo
How seawater and limestone could be used to reduce maritime emissions
With Canada and other countries looking to increase the sales of electric vehicles (EV) as a mean to help reduce greenhouse gas emissions, what is the world doing to combat the carbon dioxide (CO2) levels emitted by marine-based transportation? Well, researchers at the Caltech and Southern California (USC) universities, working alongside a startup firm, may have found a doable solution. SEE ALSO: The answer is a shipboard system using limestone and seawater that can reportedly convert the CO2 emissions generated by shipping vessels into an ocean-safe solution. The process could cut maritime CO2 emissions by as much as 50 per cent, according to a USC news release. The concept is part of a study published in Science Advances. (Getty Images/boryak/120046804-170667a) 'What's beautiful about this is how simple it is,' said William Berelson, a USC professor and co-corresponding author in the study, in the news release. 'We're speeding up a process the ocean already uses to buffer CO2––but doing it on a ship, and in a way that can meaningfully reduce emissions at scale.' According to the authors of the study, the process imitates a natural chemical reaction in the ocean. As the ships traverse through seawater, CO2 released from the exhaust is digested into water that is pumped on board, making it "slightly more acidic." Following that, the water proceeds to move through a patch of limestone, where the acid reacts with the rock to form bicarbonate, which is naturally found in seawater as a safe and stable compound. The now-treated water, free of CO2, is then released back into the ocean. (Getty Images/Ultramansk/2222108057-170667a) 'What's most exciting to me is that this started as a pure science question: 'How does the ocean buffer CO2?'' said Berelson. 'From there, we realized we might have a real-world solution that could help fight climate change.' The study noted that maritime shipping produces almost three per cent of global greenhouse gas emissions. Any current solutions to address the ocean emissions, such as low-carbon fuels and electrification, are still too expensive or not feasible for treks that are of long-distances, according to USC. The research on the shipboard system is being conducted with Calcarea––a startup company working on getting the technology to market. Right now, Calcarea is in early talks with commercial shippers and reviewing pilot programs that would test the technology on operable vessels. While doing work on the shipboard in the lab, those involved in the study experimented on vital elements of the process, utilizing controlled amounts of seawater, limestone and CO2. Their tests were matched closely with theoretical projections, boosting the researchers' confidence in being able to "scale up their modelling" to the size needed to work on real vessels, the Southern California university said. (Getty Images/FangXiaNuo/1155475425-170667a) 'We see our approach as a complementary strategy that could help ships reduce their environmental impact without major design overhauls,' said Jess Adkins, co-founder and CEO of Calcarea and a professor at Caltech, in the USC news release. As well, the examination also used advanced ocean modelling to analyze any potential impacts after the bicarbonate-rich water is put back into the ocean. A hypothetical ship taking multiple trips between China and Los Angeles over a 10-year period was monitored in simulations, with data keeping tabs the vessel discharging treated water along the route. The models showed an inconsequential impact on ocean pH and chemistry, USC said, demonstrating an "important validation" for the technology's environmental safety. Meanwhile, research on the initiative continues from Calcarea, with inquiries into reaction rates and long-term impacts on ocean chemistry. Click here to view the video With files from the University of Southern California. Thumbnail courtesy of Getty Images/HeliRy/183238611-170667a. Follow Nathan Howes on X and Bluesky.
Yahoo
04-07-2025
- Science
- Yahoo
Red, white and blue on the Red Planet
July 3 (UPI) -- On the eve of the 249th anniversary of American independence, NASA on Tuesday showcased a patriotic image of Old Glory as seen from hundreds of millions of miles away. A plaque bearing the United States flag is on an aluminum plate at the base of the mast, or "head," of NASA's Perseverance rover on the Red Planet. An image of the flag was taken on June 28 by the WATSON (Wide Angle Topographic Sensor for Operations and eNgineering) camera on the end of the rover's robotic arm. On Tuesday, NASA published an image of the flag on the rover, as seen during its 1,548th day of its mission. WATSON was built by Malin Space Science Systems in San Diego and is operated jointly by Malin Space Science Systems and NASA's Jet Propulsion Laboratory in Southern California. JPL, managed by Caltech, built and manages operations of Perseverance. The first U.S. flag planted somewhere besides Earth was the one planted on the moon by Buzz Aldrin in 1969. It signaled the United States had won the so-called Space Race with the Soviet Union.
Yahoo
03-07-2025
- Science
- Yahoo
A Fusion Rocket Could Soon Reach a World We Haven't Seen Since the Stone Age
Here's what you'll learn when you read this story: In 2076, the dwarf planet Sedna will make its closest approach to the Sun in 11,400 years, and scientists are now figuring out the best way to visit the outer solar system visitor before its too late. Although this is its 'closest' approach, Sedna will still be more than twice the distance that Sun is from Pluto, so any mission will have a plethora of challenges, including how to get there in the first place. A new study examines the possibility of using direct fusion drives (DFD) or solar sails for such a mission, and while each have their benefits, a reliable fusion drive could deliver a 1,500 kg payload in orbit around Sedna, providing an unprecedented opportunity to learn about the furthest reaches of the Solar System. The story of the past 35 years in astronomy has been discovering just how massive our Solar System really is. In 1992, astronomers spotted the minor planet 15760 Albion, the first object ever spotted beyond Pluto and the first official member of the Kuiper Belt. Later, at the turn of the century, astronomers (especially Mike Brown at Caltech) made a string of discoveries, including Quaoar, Maki, Makemake, Eris, and Sedna. Although these discoveries in aggregate is what eventually doomed Pluto to a planetary demotion (Eris is just a sliver smaller than pluto), Sedna was particularly eye-catching. Roughly three times smaller than our Moon, Sedna has an extremely narrow and elliptical orbit, making its closest approach to the sun (perihelion) at roughly 76 AU—some 12.3 times closer than its aphelion at 937 AU. This makes Sedna a kind of planetary emissary to the far-flung Oort cloud. Oh, and astronomers discovered another interesting aspect about Sedna: Its closest approach was just one human lifetime away. Fast-forward 22 years from its initial discovery and astronomers are debating how to best study this astronomical event that hasn't occurred since humans first developed agriculture during the tail end of the Stone Age. A new study, published in the online preprint server arXiv, scientists from the U.S. and Italy analyze a hypothetical mission using two distinct approaches—solar sails and direct fusion drives (DFD). While conventional propulsion systems could require up to 30 years to perform a flyby maneuver, both solar sails and DFDs could pull off the feat in about one-third of the time. However, the outcomes of those twin missions would be vastly different because a DFD drive could actually perform an orbital insertion maneuver whereas a solar sail would be a strictly flyby mission, much like New Horizons swinging by Pluto in 2015. 'Due to the limitations of traditional methods, innovative propulsion systems are crucial to reach distant targets like Sedna,' the authors write. 'Chemical propulsion, while providing high thrust for launches, suffers from low efficiency and high fuel mass requirements for long-duration missions. Electric propulsion, including ion and Hall effect thrusters, offers much higher efficiency and finds many applications nowadays but produces insufficient thrust for rapid deep-space travel.' A DFD, like the Princeton Field-Reversed Configuration (PFRC), would by and large be the preferred method. By the study's estimates, a fusion drive would reduce the mission time compared to conventional rockets by 50 percent while also delivering a 1500 kg payload, which is 1,000 times more than the solar sail alternative. However, this is far from a fool-proof plan. For one, fusion drives have yet to prove plasma stability and reliability during deep-space missions and that's not even beginning to consider things like communication. Secondly, while Sedna is making its 'closest' approach in 2076, it's still more than double the distance from the Sun to Pluto, meaning one-way-light-time (OWLT) would be about 13 hours—not exactly an easy environment for reliable communication. Sending a spacecraft to Sedna would be one of the greatest challenges in the history of spaceflight, but a rewarding one. Due to its extremely strange orbit, Sedna could provide an unprecedented opportunity to learn about some of the farthest reaches of our own Solar System. Luckily, we still have a few more years to perfect a mission (especially if we go the DFD route), but scientists would need to get working sooner rather than later so that this once-in-140-lifetimes opportunity doesn't slip through our orbital grasp. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
