It's a regrettable reality that there is never time to cover all the interesting scientific stories we come across each month. In the past, we've featured year-end roundups of cool science stories we (almost) missed. This year, we're experimenting with a monthly collection. May's list includes a nifty experiment to make a predicted effect of special relativity visible; a ping-pong playing robot that can return hits with 88 percent accuracy; and the discovery of the rare genetic mutation that makes orange cats orange, among other highlights.
Credit:
TU Wien
Perhaps the most well-known feature of Albert Einstein's special theory of relativity is time dilation and length contraction. In 1959, two physicists predicted another feature of relativistic motion: An object moving near the speed of light should also appear to be rotated. It has not been possible to demonstrate this experimentally, however—until now. Physicists at the Vienna University of Technology figured out how to reproduce this rotational effect in the lab using laser pulses and precision cameras, according to a paper published in the journal Communications Physics.
© David Nguyen, Kendrick Cancio and Sangbae Kim
Several years ago, Harvard University roboticist Robert Wood made headlines when his lab constructed RoboBee, a tiny robot capable of partially untethered flight. Over the years, RoboBee has learned to fly, dive, and hover. The latest improvement: RoboBee has learned how to stick the landing, thanks to biomechanical improvements to its landing gear modeled on the crane fly, which has a similar wingspan and body size to the RoboBee platform. The details of this achievement appear in a new paper published in the journal Science Robotics.
As previously reported, the ultimate goal of the RoboBee initiative is to build a swarm of tiny interconnected robots capable of sustained, untethered flight—a significant technological challenge, given the insect-sized scale, which changes the various forces at play. In 2019, Wood's group announced its achievement of the lightest insect-scale robot so far to have achieved sustained, untethered flight—an improved version called the RoboBee X-Wing. In 2021, Wood's group turned its attention to the biomechanics of the mantis shrimp's knock-out punch and built a tiny robot to mimic that movement.
But RoboBee was not forgotten, with the team focusing this time around on achieving more robust landings. “Previously, if we were to go in for a landing, we’d turn off the vehicle a little bit above the ground and just drop it, and pray that it will land upright and safely,” said co-author Christian Chan, one of Wood's graduate students. The trick is to minimize velocity when approaching a surface and then quickly dissipating impact energy. Even something as small and light as RoboBee can generate significant impact energy. The crane fly has long, jointed appendages that enable them to dampen their landings, so the insect served as a useful model for RoboBee's new landing gear.
© Harvard Microrobotics Laboratory
Even the tiniest of living things are capable of some amazing forms of locomotion, and some come with highly sophisticated sensor suites and manage to source their energy from the environment. Attempts to approach this sort of flexibility with robotics have taken two forms. One involves making tiny robots modeled on animal behavior. The other involves converting a living creature into a robot. So far, either approach has involved giving up a lot. You're either only implementing a few of life's features in the robot or shutting off most of life's features when taking over an insect.
But a team of researchers at Harvard has recognized that there are some behaviors that are so instinctual that it's possible to induce animals to act as if they were robotic. Or mostly robotic, at least—the fruit flies the researchers used would occasionally go their own way, despite strong inducements to stay with the program.
The first bit of behavior involved Drosophila's response to moving visual stimuli. If placed in an area where the fly would see a visual pattern that rotates from left to right, the fly will turn to the right in an attempt to keep the pattern stable. This allowed a projector system to "steer" the flies as they walked across an enclosure (despite their names, fruit flies tend to spend a lot of their time walking). By rotating the pattern back and forth, the researchers could steer the flies between two locations in the enclosure with about 94 percent accuracy.
© arlindo71
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