Matterhorn sways to a seismic beat, interstellar propulsion system remains science fiction, goldfish drives a car

07 Jan 2022 Hamish Johnston

Swaying to the beat: the Matterhorn oscillates at 0.42 Hz. (Courtesy: Zacharie Grossen - Camptocamp.org/CC BY-SA 3.0)

The Matterhorn, an Alpine peak that straddles the border between Switzerland and Italy, is one of the most iconic mountains in the world. Isolated at the head of the Zermatt Valley, climbing the perfectly shaped mountain, which has a summit height of 4470 m above sea level, is on the to-do list of thousands of climbers – and some physicists. In 2019, an international team of scientists set out to take a closer look at the Matterhorn and installed several seismometers at different locations to record its movement. They found that despite the Matterhorn appearing like a huge immovable mass, it is in fact constantly on the move, swaying gently back and forth about once every two seconds. The researchers say that this subtle vibration, with a fundamental frequency of 0.42 Hz, is stimulated by seismic energy in the Earth originating from oceans and earthquakes, as well as – rather surprisingly – human activity. The mountain’s motion is described in Earth and Planetary Science Letters.

What kind of propulsion system would make it possible to bridge the enormous distances between the stars? Ordinary rockets like those used to travel to the Moon or Mars won’t cut it, which has led to several speculative ideas for interstellar travel. One of which is the “Bussard collector” or “Ramjet propulsion” that was dreamt up in the 1960s by the US nuclear physicist Robert Bussard. It involves capturing protons in interstellar space and then using them for a nuclear fusion reactor.

Peter Schattschneider, a physicist at the Technical University of Vienna, and Albert Jackson from private firm Triton Systems LLC in the US, say that the basic principle of magnetic particle trapping does in fact work. They have shown that particles can be collected in the proposed magnetic field and guided into a fusion reactor. In theory, considerable acceleration can be achieved – up to relativistic speeds. But there is a big caveat. To achieve a thrust of 10 million Newtons – equivalent to twice the main propulsion of the Space Shuttle – the “magnetic funnel” to guide the particles would have to be about 150 million kilometres long – the distance between the Sun and the Earth. After half a century of hope for interstellar travel, the ramjet drive, alas, remains purely science fiction. You can read more in Acta Astronautica.

Gazing goldfish

Can a goldfish drive a car on land? Yes, according to researchers in Israel who have built a fish operated vehicle (or FOV) – essentially a fish tank on four wheels. The car moves according to the actions of the fish, which are captured by a camera. If the fish is at an edge of the tank and gazing outwards, the FOV moves in the direction of the fish’s gaze.

The FOV was placed in an arena with a large pink target that was visible to the fish. If the fish steered the vehicle to the target, it would receive a food pellet. As well as successfully manoeuvring the car to the target after a few days of training, the six goldfish tested were also able deal with changes within the arena that had the potential to confuse them.

“The study hints that navigational ability is universal rather than specific to the environment. Second, it shows that goldfish have the cognitive ability to learn a complex task in an environment completely unlike the one they evolved in. As anyone who has tried to learn how to ride a bike or to drive a car knows, it is challenging at first,” says Shachar Givon at Ben-Gurion University of the Negev. The research is described in Behavioural Brain Research and you can watch a video of a fish operating the FOV here.

from physicsworld.com     7/1/2022