What is the significance of a magnetic field

Please support us by making a donation or purchasing a subscription today. Share Tweet. Terrestrial magnetic field, similar to magnetic field of bar magnet tilted 11 degrees from spin axis of Earth. More on:. More from:. Vishnu Varma R Vejayan. Read science facts, not fiction See magnet and magnetism. New Word List Word List.

Save This Word! See synonyms for magnetic field on Thesaurus. We could talk until we're blue in the face about this quiz on words for the color "blue," but we think you should take the quiz and find out if you're a whiz at these colorful terms.

Origin of magnetic field First recorded in — Words nearby magnetic field magnetic disk , magnetic domain , magnetic drum , magnetic epoch , magnetic equator , magnetic field , magnetic field of the Earth , magnetic field reversals , magnetic field strength , magnetic flux , magnetic flux density.

Words related to magnetic field electromagnetic field. How to use magnetic field in a sentence Because they are not deflected by magnetic field s, gamma rays point back to their sources, revealing the whereabouts of the itinerant cosmic rays.

Using magnetic instruments adapted from airborne magnetic anomaly detectors developed during World War II to detect submarines, the magnetic variations across the ocean floor have been mapped. The basalt — the iron-rich, volcanic rock making up the ocean floor — contains a strongly magnetic mineral magnetite and can locally distort compass readings. The distortion was recognized by Icelandic mariners as early as the late 18th century.

More important, because the presence of magnetite gives the basalt measurable magnetic properties, these magnetic variations have provided another means to study the deep ocean floor. When newly formed rock cools, such magnetic materials record the Earth's magnetic field. Frequently, the Earth's magnetosphere is hit by solar flares causing geomagnetic storms , provoking displays of aurorae.

The short-term instability of the magnetic field is measured with the K-index. Recently, leaks have been detected in the magnetic field, which interact with the Sun's solar wind in a manner opposite to the original hypothesis. During solar storms , this could result in large-scale blackouts and disruptions in artificial satellites.

Based upon the study of lava flows of basalt throughout the world, it has been proposed that the Earth's magnetic field reverses at intervals, ranging from tens of thousands to many millions of years , with an average interval of approximately , years. There is no clear theory as to how the geomagnetic reversals might have occurred.

Some scientists have produced models for the core of the Earth wherein the magnetic field is only quasi-stable and the poles can spontaneously migrate from one orientation to the other over the course of a few hundred to a few thousand years.

Other scientists propose that the geodynamo first turns itself off, either spontaneously or through some external action like a comet impact , and then restarts itself with the magnetic "North" pole pointing either North or South.

External events are not likely to be routine causes of magnetic field reversals due to the lack of a correlation between the age of impact craters and the timing of reversals.

Regardless of the cause, when the magnetic pole flips from one hemisphere to the other this is known as a reversal, whereas temporary dipole tilt variations that take the dipole axis across the equator and then back to the original polarity are known as excursions. Studies of lava flows on Steens Mountain , Oregon, indicate that the magnetic field could have shifted at a rate of up to 6 degrees per day at some time in Earth's history, which significantly challenges the popular understanding of how the Earth's magnetic field works.

Paleomagnetic studies such as these typically consist of measurements of the remnant magnetization of igneous rock from volcanic events. Sediments laid on the ocean floor orient themselves with the local magnetic field, a signal that can be recorded as they solidify. Although deposits of igneous rock are mostly paramagnetic , they do contain traces of ferri - and antiferromagnetic materials in the form of ferrous oxides, thus giving them the ability to possess remnant magnetization. In fact, this characteristic is quite common in numerous other types of rocks and sediments found throughout the world.

One of the most common of these oxides found in natural rock deposits is magnetite. As an example of how this property of igneous rocks allows us to determine that the Earth's field has reversed in the past, consider measurements of magnetism across ocean ridges.

Before magma exits the mantle through a fissure, it is at an extremely high temperature, above the Curie temperature of any ferrous oxide that it may contain. The lava begins to cool and solidify once it enters the ocean, allowing these ferrous oxides to eventually regain their magnetic properties, specifically, the ability to hold a remnant magnetization. Assuming that the only magnetic field present at these locations is that associated with the Earth itself, this solidified rock becomes magnetized in the direction of the geomagnetic field.

Although the strength of the field is rather weak and the iron content of typical rock samples is small, the relatively small remnant magnetization of the samples is well within the resolution of modern magnetometers. A classic example of a magnetic field is the field created by an iron magnet. As previously mentioned, the magnetic field can be illustrated by surrounding it with iron filings, which will be attracted to its field lines and form in a looping formation around the poles.

Credit: NASA Such a field is called a dipole field because it has two poles — north and south, located at either end of the magnet — where the strength of the field is at its maximum. Other celestial bodies have been shown to have magnetic fields of their own. However, due to either a massive collision , or rapid cooling in its interior , Mars lost its magnetic field billions of years ago. It is because of this that Mars is believed to have lost most of its atmosphere , and the ability to maintain liquid water on its surface.

When it comes down to it, electromagnetism is a fundamental part of our Universe, right up there with nuclear forces and gravity.

Understanding how it works, and where magnetic fields occur, is not only key to understanding how the Universe came to be, but may also help us to find life beyond Earth someday. We have written many articles about the magnetic field for Universe Today. Listen here, Episode Earth. I have always wondered what mechanism does a magnetic force uses to move objects attracted to a magnet or being repelled as in same magnetic poles. This mechanism is invisible, and works through non-metallic barriers such as paper, wood etc.

In a similar situation with the case of forces of gravity, we now know that gravity works by distorting space-time, so objects within it is sort of pushed around by the thinned-out space. How does magnetism do it? Physicists say that it is the exchange of virtual photons.

The idea is that all forces are manifest by the exchange of the characteristic force particles. The math works out, as I understand it. The reason why most metallic objects provide effective shielding against EM fields is due to the electrical conductivity of the material. I see you are slowly realizing the importance of electromagnetism in the structure and function of the universe.

The massive magnetic fields being measured by nearly every NASA mission to the sun and deep space are undeniable.

The obvious fact that accompanies these findings is that there is an electric current flow of charged particles that occurs concomitantly with every magnetic field. It is clear that everything we see in space is due to the radiation generated from plasma in the glow mode. So it would be wise to consider the electromagnetic nature of the universe rather than create mystical entities that defy the laws of physics to explain it.