Просмотр новости
Найдите то, что Вас интересует
Спутники
РН
SpaceX
Роскосмос
NASA
СпутникиРНSpaceXРоскосмосNASAThese super high-tech timepieces use the chemical element thorium to keep time. And as the clocks improve, they could help solve some mysteries in physics.
For the first time, scientists have used an atomic nucleus as a clock.
Clocks need to keep a steady rhythm. (Think of the swinging pendulum in a grandfather clock.) The new clocks are based on how light interacts with an atomic nucleus — the collection of protons and neutrons at the center of an atom. This technique could allow scientists to make clocks that tick more precisely than any before.
The world’s most precise timepieces are already made using atoms. Existing atomic clocks rely on their electrons. Clocks based on atomic nuclei might perform even better. Now, two teams of scientists have finally made the first nuclear clocks.
This tech is still at an early stage. So nuclear clocks don’t yet tick more precisely than atomic clocks. But these new clocks can already test physics in novel ways.
A research team used one of these clocks to search for dark matter. That’s an unidentified substance that makes up much of the universe. The team describes its new clock — and the search — in a paper submitted June 3 to arXiv.org. This nuclear clock didn’t find any dark matter. But it seems to be more sensitive to some types than atomic clocks. In that search, “we’re already outperforming all of the atomic clocks,” reports Thorsten Schumm. He’s a physicist on the project at Vienna University of Technology in Austria.
“This is an outstanding result,” says Victor Flambaum, who did not take part in the work. A theoretical physicist, he works at the University of New South Wales in Sydney, Australia. The new feat should spur more progress, he says. “This is only the first step. [The] race for building super-accurate nuclear clocks just started.”
Submit your question here, and we might answer it an upcoming issue of Science News Explores
Nuclear clocks have the potential to weigh in on other weird physics, too. That’s why they’re “one of the most actively pursued frontiers,” says Shiqian Ding. He’s a physicist at Tsinghua University in Beijing, China. Ding’s team made a nuclear clock based on a technology similar to Schumm’s. They described this second clock in a paper submitted June 7 to arXiv.org. (Neither paper has been peer reviewed.)
Both clocks contain crystals of calcium fluoride. Embedded in those crystals are atoms of thorium-229, a radioactive isotope. That thorium is key. In the entire periodic table, it’s the only element whose atomic nucleus can be used to make a clock.
Scientists hit that thorium-229 with a laser. The wiggling electromagnetic waves of laser light acted like a clock’s swinging pendulum. Thorium’s role was to make sure that the frequency of those waves didn’t change. This kept the “ticking” of these clocks from slowing or speeding up.
The way this works is based on quantum physics, the branch of science that describes atoms and similarly tiny stuff. According to quantum physics, a nucleus can hold only certain amounts of energy. That gives each nucleus a set of energy levels. A jump between two particular energy levels of a given atom always takes the same amount of energy.
So the laser’s frequency was locked to a jump between energy levels in the thorium nucleus. Only the right frequency of light will make that jump take place. Scientists used the jump to readjust the laser. They did this over and over to keep the ticks steady.
Thorium-229 is the only atomic nucleus that has an energy jump of a size that will be initiated by a laser. So it’s the only one that can be used to make a clock.
Although scientists have previously gotten close to making nuclear clocks, this readjustment step had never been done before.
“This was the final missing step before calling it an actual clock,” says Lars von der Wense, who also was not involved with the research. A physicist, he works at Johannes Gutenberg University Mainz in Germany. With improvements to lasers and crystals on the horizon, he says, nuclear-clock technology is expected to advance rapidly.
Improving on atomic clocksNuclear clocks have been hotly anticipated. Compared with atomic clocks, they’re less sensitive to stray electromagnetic fields that can throw them off. And they can be made out of solid materials. The atoms in atomic clocks must be suspended in a cumbersome vacuum chamber. These traits have scientists hoping for more portable, robust clocks.
And atomic nuclei respond to different forces than electrons. Electrons mainly are subject to electromagnetic forces. In contrast, the strong nuclear force holds protons and neutrons together. That opens up new possibilities for study.
Numbers called fundamental constants determine the relative strength of those forces. Comparisons of an atomic clock to a nuclear one could be used to check if those numbers really stay constant over time.
It’s been a long wait — almost a quarter century — since scientists first dreamt of a thorium nuclear clock. But “I have always been optimistic about the success of this project,” says Ekkehard Peik. He’s a physicist at the National Metrology Institute in Braunschweig, Germany. Peik is one of the scientists who proposed the idea for such a clock and was a coauthor with Schumm on a paper describing the new clocks.
After initially slow progress, researchers have made rapid advances in recent years. Now, Peik says, “a great deal of interesting research … is only just beginning.”
atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
atomic: Having to do with atoms, the smallest possible unit that makes up a chemical element.
atomic clock: A timekeeping device that relies on the frequency of microwave emissions from excited atoms. For example, for the cesium atom that frequency is 9,192,631,770 hertz (or cycles/oscillations per second). Many common devices including cell phones, computers and GPS-satellite receivers rely on the high accuracy of atomic clocks to regularly reset their time (known as synchronization).
calcium: A chemical element and alkali metal common in minerals of the Earth’s crust and in sea salt. It is also found in bone mineral and teeth, and can play a role in the movement of certain substances into and out of cells.
coauthor: One of a group (two or more people) who together had prepared a written work, such as a book, report or research paper. Not all coauthors may have contributed equally.
constant: (in mathematics) A number that is known and unchanging, usually based on some mathematical definition. For example, π (pi) is a constant equal to 3.14. . . and defined as the circumference of a circle divided by its diameter.
crystal: (adj. crystalline) A solid consisting of a symmetrical, ordered, three-dimensional arrangement of atoms or molecules. It’s the organized structure taken by most minerals. Apatite, for example, forms six-sided crystals. The crystalline components of a rock are usually too small to be seen with the unaided eye.
dark matter: Physical objects or particles that emit no detectable radiation of their own. They are believed to exist because of unexplained gravitational forces that they appear to exert on other, visible astronomical objects.
electromagnetic: An adjective referring to light radiation, to magnetism or to both.
electromagnetic force: (also known as electromagnetism) One of the four fundamental forces of nature. It’s the force that causes electrically charged particles to interact. The regions over which these interactions occur are known as electromagnetic fields.
electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.
element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.
field: (in physics) A region in space where certain physical effects operate, such as magnetism (created by a magnetic field), gravity (by a gravitational field), mass (by a Higgs field) or electricity (by an electrical field).
fluoride: A chemical, such as sodium fluoride, that contains the element fluorine. In small doses, fluorides can help prevent tooth decay.
force: Some outside influence that can change the motion of an object, hold objects close to one another, or produce motion or stress in a stationary object.
frequency: The number of times some periodic phenomenon occurs within a specified time interval. (In physics) The number of wavelengths that occurs over a particular interval of time.
fundamental: Something that is basic or serves as the foundation for another thing or idea.
laser: A device that generates an intense beam of coherent light of a single color. Lasers are used in drilling and cutting, alignment and guidance, in data storage and in surgery.
magnetic field: An area of influence created by certain materials, called magnets, or by the movement of electric charges.
matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."
metrology: The scientific field devoted to understanding how best to measure things. People who work in this field are known as metrologists.
neutron: A subatomic particle carrying no electric charge that is one of the basic pieces of matter. Neutrons belong to the family of particles known as hadrons.
nuclear clock: A timekeeping device that’s based on changes in the energy states of an atom’s nucleus (rather than its electrons, which drive the high precision of the older technology of atomic clocks). The clocks are potentially more robust and accurate than atomic clocks.
nucleus: Plural is nuclei. (in biology) A dense structure present in many cells. Typically a single rounded structure encased within a membrane, the nucleus contains the genetic information. (in astronomy) The rocky body of a comet, sometimes carrying a jacket of ice or frozen gases. (in physics) The central core of an atom, containing most of its mass.
peer review: (in research) A process in which experts in a field carefully read and critique the work of their peers before it is published in a research journal. Peer review helps to prevent sloppy science and bad mistakes from being published.
physics: The scientific study of the nature and properties of matter and energy. Classical physics is an explanation of the nature and properties of matter and energy that relies on descriptions such as Newton’s laws of motion. Quantum physics, a field of study that emerged later, is a more accurate way of explaining the tiny motions and behavior of matter about the size of electrons. A scientist who works in such areas is known as a physicist.
proton: A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.
radioactive: An adjective that describes unstable elements, such as certain forms (isotopes) of uranium and plutonium. Such elements are said to be unstable because their nucleus sheds energy that is carried away by photons and/or one or more subatomic particles. This emission of energy is by a process known as radioactive decay.
technology: The application of scientific knowledge for practical purposes, or the devices, processes and systems that result from those efforts.
theoretical: An adjective for an analysis or assessment of something based on pre-existing knowledge of how things behave. It is not based on experimental trials. Theoretical research tends to use math — usually performed by computers — to predict how or what will occur for some specified series of conditions. Experimental testing or observations of natural systems will then be needed to confirm what had been predicted.
theoretical physicist: A scientist who studies the nature and properties of matter and energy through math — usually performed by computers. Their analyses or assessments will be based on already existing knowledge of how things behave. Such theoretical research tends to predict how or what will occur for some specified series of conditions. Experimental testing or observations of natural systems will then be needed to confirm such predictions.
thorium: A naturally radioactive element which appears as a silvery metal when it is pure. It reacts chemically with air, turning black on its surface. It is found in some minerals, and can be used to trace the source of some mineral grains that are carried long distances by water or wind. Its scientific symbol is Th.
trait: A characteristic feature of something.
universe: The entire cosmos: All things that exist throughout space and time. It has been expanding since its formation during an event known as the Big Bang, some 13.8 billion years ago (give or take a few hundred million years).
vacuum: Space with little or no matter in it. Laboratories or manufacturing plants may use vacuum equipment to pump out air, creating an area known as a vacuum chamber.
wave: A disturbance or variation that travels through space and matter in a regular, oscillating fashion.
Science News physics writer Emily Conover studied physics at the University of Chicago. She loves physics for its ability to reveal the secret rules about how stuff works, from tiny atoms to the vast cosmos.
| # | Наименование новости | Тональность | Информативность | Дата публикации |
|---|---|---|---|---|
| 1 | An old jeweler’s trick could change nuclear timekeeping | 0 | 6.84 | 09-01-2026 |
| 2 | Physicists created a tiny universe where time emerged without a clock | 0 | 7.31 | 09-07-2026 |
| 3 | Исследование: новые сверхточные атомные часы позволят измерять длину секунды точнее | 0 | 0 | 29-11-2018 |
| 4 | Ядерные часы улучшат навигационные системы | 0 | 0 | 01-08-2025 |
| 5 | Scientists connect “time crystal” to real device in quantum breakthrough | 0 | 6.66 | 05-05-2026 |
| 6 | Long-lived ytterbium states could sharpen quantum computing and atomic clocks | 0 | 8.57 | 24-07-2026 |
| 7 | 🔮⏱ Британцы сделали прорыв: радары работают без GPS — и ... | 0 | 5.3 | 18-08-2026 |
| 8 | Physicists Discover Time Crystals Can Communicate Across a Semiconductor | 0 | 17.18 | 24-08-2026 |
| 9 | Schrödinger’s clock: Time could tick faster and slower at the same time | 0 | 6.1 | 18-05-2026 |