If you’ve ever held a magnet in your hand, you probably know that it produces an invisible moving electric charge called a magnetic field. But what exactly makes it work?
Earth’s field, for instance, comes from a dynamo, the current of liquid iron churning inside our planet’s core. The fields of fridge magnets and lodestones, on the other hand, come from electrons spinning around their constituent atoms.
Electromagnets
Using magnets is common in everyday life, from electric cars and vacuum cleaners to refrigerators and tumble driers. Electromagnetic components are also found in many scientific and medical equipment, such as magnetic resonance imaging (MRI) machines and nuclear magnetic resonance spectrometers.
The ability to manipulate objects without contact is one of the most useful properties of a magnet. It has been used for a wide range of applications, from guiding space debris to repairing satellites, as well as for controlling the movement of robotic devices like rovers.
Researchers have recently developed a technique that can control the spin of copper spheres, mimicking the non-friction environment of space. They hope that it will one day be able to be used to slow down space debris, or even repair a damaged satellite.
In order to achieve this, scientists have designed a device called an electromagnet. The device works by passing electricity through a metal wire coil which creates a magnetic field. When this magnetic field is stronger than the surrounding air or gravity, the metal will become magnetized and attract other materials.
This effect is controlled by switching current flow through the coils on and off. In addition, the direction of the flow is also manipulated by changing the angle of the current.
These magnetic fields can be powerful, but it’s important to note that they are temporary and will not last forever. They only become strong when the electricity is flowing and they weaken if they lose power.
The strongest magnetic fields are made by pulsed electromagnets, which use explosives to compress the magnetic field as it is pulsed, in a process known as “explosively pumped flux compression generators.” These generators can reach a strength of up to 1000 T in a few microseconds.
They’re used for a variety of research projects, including testing the effects of high-temperature superconductivity on materials like gold, as well as to generate powerful magnetic fields for magnetic resonance imaging and other applications. The most powerful pulsed electromagnets are also capable of delivering energy to the surface of a solid, by converting a small amount of power from the magnetic field into electricity.
Permanent magnets
A magnet is a material that is magnetized and creates its own persistent magnetic field. This field is what attracts other magnets and repels other non-magnetic materials.
Magnets are a common component of many everyday objects and equipment. They are used in a wide range of applications, including audio equipment, MRI scanners and hard disc drives in computers.
They are also used in space to power satellites and a variety of other technologies. For example, the Alpha Magnetic Spectrometer (AMS) on the International Space Station generates a magnetic force that is 20,000 times stronger than Earth’s.
Permanent magnets are often made of ferromagnetic materials or metal alloys, such as iron, nickel, cobalt, gadolinium, lodestone, and manganese. These materials are very easy to influence by an external magnetic field, and they retain magnetism for a relatively long time even after removing the magnetic field from them.
These magnetic fields are invisible to the human eye, but astronomers have found them permeating the vast expanse of space. Astronomers have discovered that these magnetic force fields are attracting ferromagnetic matter from other galaxies, as if the universe were a giant magnet.
The magnetism emitted by these ferromagnetic particles is so powerful that it can swoop through the gaps in intergalactic space like the grooves of a fingerprint. These forces — known as synchrotron signals — are not detectable by the human eye or other detectors because they keep low profiles.
This makes it very difficult to capture the elusive phenomenon of these force fields. But a team of astronomers has been successful in detecting these force fields using an array of low-frequency radio antennas across Europe.
They have been able to pinpoint the location of these magnetized filaments by studying the patterns they leave behind on the sky. The resulting data has allowed astronomers to track the accelerating motion of stars in the cluster, as well as the flow of gas from the cluster into intergalactic space.
This information is being used to design future spacecraft. Ultimately, the hope is to use magnets in space to power spacecraft that could explore the farthest reaches of our universe.
Space applications
In space, magnets help to orient satellites and stabilize them in orbit by using magnetic torques. These forces are much smaller than the force of gravity on Earth, and they are important for controlling the attitude, detumbling and stabilization of satellites, which can be up to several metric tons in mass.
One of the most common applications for magnets in space is the guidance and navigation systems of satellites. These devices help to steer the satellites through space and ensure their safe arrival at their destination, making them reliable and less likely to be damaged.
Another important application for magnets in space is for astronomy. For example, the Alpha Magnetic Spectrometer used on the International Space Station was built to study particles from cosmic phenomena such as black holes and dying stars by using a really strong permanent magnet.
The AMS uses a 1200 kilogram (2,645 pound) permanent neodymium magnet to generate the high magnetic field it needs to detect and track particles. When charged particles enter the AMS they bend in different ways based on their charges, and this helps scientists study antimatter and dark matter.
As the ISS and other space stations have gotten bigger, they have needed larger magnets to power their electronics. These magnets have been manufactured by Raytheon, MIT Instrumentation Laboratory and other companies to power the station’s computers.
Besides the use of magnets to drive these computers, many other uses have been made for magnets in space. These include sensors that detect the position and speed of an actuator, fluid flow rates, fuel pumps and temperature generators.
In addition, magnetic devices have been used to create the flight control covers for commercial and military aircraft. They can reduce the amount of carbon dioxide produced by the aircraft and can be reused and recycled more easily.
As the concept of miniaturized sensors has gained popularity, the magnetic sensors used on-board satellites are becoming increasingly smaller and light in weight. A trend is also emerging towards the development of new and mature off-the-shelf technologies that have a lower cost and high performance than rad-hardened components, especially for those with very low power consumption requirements like geomagnetic field mapping or ACS-Attitude Control System.
Future applications
Magnets play a huge role in space exploration, from guiding satellites to holding experiments in place. It’s a fact that magnets are key to many of the successful missions that we’ve seen, from Apollo 11 to the latest mission to Mars.
One of the most important uses for magnets is in the magnetic torquer, also known as a Magnetorquer, which is found on spacecraft to control their attitude. The magnetic torquer works by interacting with the Earth’s magnetosphere to help locate and control the satellite’s orientation in space.
Another great application for magnets in space is the use of magnetic levitation, a technology that can create frictionless and efficient ways to move objects. It can be used in liquid robotics, for instance, to move and deliver active matter without the need for any propellant.
This technology has been around for a while, but new research by Dr Michael Shay at the University of Delaware is making it more accessible to scientists. In this study, he and colleagues describe a’reconfigurable ferromagnetic liquid droplet’ that can be created using traditional ‘ferromagnetic’ materials.
The researchers say that these nanoscale liquid droplets could be the basis of magnetically actuated liquid robotics and other liquid vessels for delivering active matter, as well as information technology with programmable liquid droplet patterns. They’ve developed the technology by working with a team of researchers at the Center for Applied Space Technology and Microgravity (ZARM) in Germany.
They conducted their research in a ‘drop tower’ that simulates microgravity conditions. They were able to successfully demonstrate that bubbles of gas can be ‘attracted to’ and’repelled from’ a neodymium magnet in a liquid solution in microgravity.
This is exciting work because it demonstrates for the first time that the same principle can be used in space. This opens up a whole new range of applications for the team’s work, such as developing oxygen systems for astronauts on space stations or other research projects that involve liquid-to-gas phase changes.
It also opens up a whole new way to build spacecraft with magnetic flight formations. Instead of relying on centrifuges that are large and energy intensive, these magnets would allow a series of spacecraft to fly in formation. These magnetic flying vehicles can all change their magnetic poles to attract or repel each other. This is a promising approach for a variety of reasons, including that the magnetic field will not be disturbed by Earth’s atmosphere. This could help the craft stay in formation for a long time and be more stable.