Astronomers have recently spotted magnetic fields permeating the cosmos. These invisible force fields — the same as those created by fridge magnets and lodestones – stretch across the universe, flattening and stiffening space like a rubber band under tension.
But do these magnets work in space? And what about other planets?
Magnets in Space
Since the first humans reached for the stars, magnets have played a huge role in space exploration. They can stick things together, repel each other and attract small charged particles known as ions. Magnets have been a vital part of many of the spacecraft that have helped us get where we are today. They’ve also been crucial to our ongoing understanding of the universe.
In addition to attracting ions, magnets can be used to create electric fields and manipulate objects that don’t have any charge. They can even help produce oxygen in microgravity. This is important as we get closer to space travel, as it will be a challenge to provide astronauts with enough oxygen for prolonged periods of time.
Magnets are incredibly important to the functioning of the International Space Station (ISS) and other spacecraft. They’re used to keep experiments stable and to protect them from vibrations, which can interfere with scientific data. They’re also a major component of many types of spacecraft engines. For example, the ISS has electromagnets called sextants that are used to measure magnetic fields.
Astronomers have also been using magnets to look for magnetic forces in ever more remote parts of the universe. Twenty years ago, scientists began to notice that magnetism permeates entire galaxy clusters and the space between galaxies. Invisible field lines swoop through the cosmos like the grooves on a fingerprint.
Magnetics are actually slightly stronger in space than on Earth. The reason is that the absence of air increases the polarization of matter, which makes it more attractive to magnets. Also, the temperature of matter affects its magnetism. Warmer matter is less magnetized, while colder matter is more magnetic.
Another interesting thing about magnets in space is that they interact with the Earth’s magnetic field. If you hold a bar magnet in weightlessness, the north side will point towards the Earth and the south side will be attracted to it. This is because of the way that the Earth’s magnetic field is generated by the movement of its liquid iron core.
Using electromagnets to move non-magnetic objects remotely could be useful for cleaning up debris in low-Earth orbit, where old satellites and other items are a growing danger. Scientists are working on ways to use them to nudge damaged satellites into new positions, so that they can be towed away for safe disposal.
Magnetic fields are everywhere—on Earth, in stars and galaxies, in the space between them. But how do they work?
Physicists have a good idea. In the simplest terms, any object that carries electric charge (either positive or negative) sets up an electromagnetic field around it. The field stretches out into the space around the object, and other charged objects will “feel” the presence of this electromagnetic field and be attracted or repelled to it.
The strength of the magnetic field depends on how much electric charge there is in a region of space, and how the charged particles in that region are oriented. When two regions are attracted to each other, the magnetic fields of the regions overlap. This causes a force called the Lorentz force to act between them. This force is proportional to the square of the distance between the regions, and it acts at a fixed speed—the same as light travels between them.
Magnetism is one of the four known fundamental forces in nature. To understand what it does, it might be useful to first consider what it doesn’t do. Magnetism doesn’t keep us on the ground or the Earth swinging around the Sun: that’s gravity’s domain. It also doesn’t bind the constituents of atoms into their nuclei or control their decay: that’s the strong nuclear force’s domain.
But electromagnetism does do some very important things. For example, we use magnets to hold materials in place and isolate experiments from vibrations onboard the ISS. Magnets can also be used to separate a sample from other surfaces on which it might come in contact. The ISS has an instrument called the Controlled Dynamics Locker, which contains an electromagnet, and a video of this device in action demonstrates how it helps scientists work on protein crystal growth without the interference of other samples or vibrations.
The Earth’s Magnetic Field
A magnet’s magnetic field can be influenced by other magnetic fields, such as those produced by atomic particles. If two magnetic fields come close together they will try to align with each other. This is what causes a compass needle to point north, for example. A magnetic field can also affect charged particles passing through it, altering their direction of movement.
The Earth’s magnetic field, which is created by electric currents in the planet’s molten iron core, creates a magnetic shield called the magnetosphere that protects the Earth from harmful cosmic radiation. This shield can even deflect high-speed particles from space, causing the Aurora Borealis (Northern Lights) when trapped plasma shoots out of the Earth’s atmosphere during magnetic storms.
Scientists use satellites to track the Earth’s magnetic field, with instruments measuring changes in its strength and direction. The data help scientists understand how the magnetosphere forms, as well as how it can be impacted by solar and cosmic events such as solar flares and coronal mass ejections.
As a bonus, the traces left by the Earth’s magnetic field in rocks allow researchers to calculate its movements in the past. This information is useful in studying the process of plate tectonics, which has resulted in the shifting of continents and ocean floors across the Earth’s surface.
Magnetic field observations also contribute to astronomical research, enabling scientists to locate objects such as comets and meteoroids. Astronomers have also used the data to construct models of the galaxy’s magnetic field, which is a key component of their understanding of how galaxies form and how they interact with each other.
The discovery of magnetism on other planets has pushed scientists to think differently about the nature of our universe. For example, a theory suggests that the universe was initially filled with a giant cloud of magnetic energy, which then collapsed into large groups of galaxies. It is thought that the magnetic energy from this primordial period has helped create the visible structures in our universe, including the luminous filaments that have been spotted recently. In addition, magnetic energy from this ancient time may have shaped the distribution of stars and planets in our galaxy and beyond.
Does Magnetism Work on Other Planets?
It’s not clear whether magnetism exists on other planets, but if it does, it would probably work in much the same way as it works here. Planets have their own magnetic fields, which emanate from their inner “dynamos,” a current of molten iron churning in their cores. These magnetic fields are a result of electrons spinning around their constituent atoms, just like the fields that arise from fridge magnets.
When two magnetic fields come close to each other, they try to align. This causes physical objects with magnetic fields to move—for example, a compass needle will always try to line up with the Earth’s field and point north. In the case of spacecraft, this phenomenon is used for propulsion purposes.
In addition to their role in guiding spacecraft, magnets are an essential tool for other types of research and exploration. They can help shield satellites from harmful radiation and even collect broken pieces of a spacecraft that have crashed into Earth’s atmosphere. Scientists also use magnets to deflect charged particles that have a net electrical charge. For instance, the charged particles produced by solar flares from the Sun can be deflected by a magnetic field.
Magnetism is one of the fundamental forces in nature, alongside gravity, electromagnetism and weak nuclear force. It’s also a key element in fusion reactors, as it can be used to create energy by converting heat into electromagnetic radiation and then back again.
Scientists have been studying magnetism for centuries, from the ancient Greeks’ discovery of naturally magnetic stones called lodestones to the Chinese’s invention of a compass that could be made to point north by stroking it against a magnetized stone. But it wasn’t until 1908 that astronomer George Ellery Hale discovered that the Sun also has its own magnetic field. Then, in 1942, Swedish physicist Hannes Alfven theorized that a planetary magnetic field can be created when electric current threads through an astrophysical object’s rotating material. This process is known as dynamo action, and it’s the reason why Earth has its strong magnetic field while Mars does not.