We often think of time as a unit of measurement for things like dates, or how long a life span is, and so on. But if you have a pair of extremely accurate timekeeping watches, you absolutely can. use the time to measure something else – measure the heights of the mountains.
According to the Los Angeles Times, this past week scientists have taken a big step forward in using time to measure altitudes above sea level. For the first time in history, they brought an entire optical atomic clock out of the lab. This watch was brought to the Alps, France.
By comparing the speed ratio of an atomic clock placed on a mountain to a similar clock in a laboratory in Turin (Italy), the researchers demonstrated that the difference in The elevation between these two locations is about 1,000 meters, or 3,280 feet. This research topic has been published in the scientific journal Natural Science.
A new atomic clock is capable of using gravity to measure the height of a mountain in the French Alps. (Photo courtesy of Jean-Pierre Clatot / AFP-Getty Images)
Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography in San Diego, said: “The idea of using a wristwatch in this way has existed in the geophysical literature for a very long time. what that researcher does is merely doing it in real life.”
According to Einstein’s theory of relativity, travel time varies depending on where you are in the gravity field. For example, a clock on the top of a high mountain – far from the center of the Earth – will move slightly faster than a clock at the bottom of that mountain, where gravity is stronger. It’s not a mechanical fault. Time is actually faster at the top of the mountain.
In other words, people living in the mountains will age a little faster than people living on the beach.
Transport optical strontium meter in the Modane Underground Laboratory. (Christian Lisdat).
“As your body ages, changes appear to exist in real time no matter where you are,” says Christian Lisdat, a physicist at the German National Institute of Metrology who did the research. “And it’s no different than a clock.”
Most modern watches are not accurate enough to mark the difference in time speed at different altitudes. Because, in 10 years, two clocks that are 1,000 meters apart by altitude would be only 31 milliseconds apart, Agnew said. But atomic clocks have the ability to split a second into so tiny pieces that this microscopic fraction can help detect a tiny change in the speed of time. Since 1655, timekeeping has been about building something that vibrates at a constant rate – whether using pendulums or those that cause quartz crystals to vibrate if you pass an electric current through them.
The same goes for atomic clocks. They use the electron’s quantum jump as a pendulum. “These jumps are a very fundamental property of atoms, and the jumps are the same for every atom of the same type,” Lisdat said. “Whatever substance you use, wherever in the universe you have the same frequency as the pendulum.” Some of the most accurate clocks on the planet are devices known as optical grid clocks . They measure the movement of electrons around strontium particles that have been trapped in a laser lattice. With this setup, an optical mesh clock can be split into 9 billion cycles per second.
Christian Lisdat, physicist at the German National Metrology Institute.
However, watches with this level of accuracy are often found in laboratories. This makes portability no less difficult, as the chamber must be maintained in a vacuum, cooling the strontium atoms to temperatures near absolute zero, creating a network of highly concentrated lasers and hundreds of mirrors. reflection, etc.
Even so, Lisdat and his colleagues wanted to build an optical grid clock that could be carried on the road. The key is to determine the factors to rebalance the stellar mass that both allow the clocks to be carried out of the laboratory without losing too much accuracy. “What we do is take something artistic and make it transportable,” says Lisdat. “It’s not easy.”
Finally, the team has broken down this optical mesh meter into small pieces that are suitable for packing on a trailer that are temperature stable and withstand great shocks, and small enough to fit in a storage compartment. two horses . “It’s like packing a small lab to take away,” Lisdat describes.
Inside the laboratory is a movable atomic clock. (Christian Lisdat).
For the first test, the authors brought their new portable watch to the Souterrain de Modane laboratory, a laboratory buried deep in the French Alps. Using an optical fiber link, they are clocked together about 88km in Turin. “We chose two relatively large altitude differences for the most effective experiment,” Lisdat shared.
The first experiments did not go well. At that time, a new tunnel was being dug underground in the mountain, and nearby drills destabilized the clock.
In addition, low humidity and warmer than expected temperatures make it a lot harder to maintain watch components. However, they were able to tell the handheld was 1,000 meters higher than the other in Turin. Eventually, as the accuracy of portable watches continued to increase, time could be used to measure the difference in height as early as about 1 cm.
Despite the difficulties, this study is considered to be useful for building improved navigation systems and helping with engineering projects. Lisdat also says that he will continue to work on this research and create new innovations in the future.