What would you say if you were asked what the single, largest structure in our solar system is?

    You might guess the Sun, but you'd be wrong. The largest structure in the solar system is Jupiter's magnetosphere.

    The magnetosphere is the area around an object, controlled by that object's magnetic field. And Jupiter's is so large, it would appear as big as the Moon if we could see it.

    But what is a magnetic field?

    Check out this guide for the ultimate FAQ session about magnetic fields. For accurate conversions between 11 common units, try our free magnetic field calculator.


    What is a magnetic field?

    In order for an object to have a magnetic field, it must first be a magnet. Only certain materials have magnetic properties.

    Iron, nickel, and cobalt are a few of these magnetic materials.

    How They Work

    A magnetic field is like an invisible bubble. It surrounds the magnet in all directions. It's the area where the magnet reacts with other magnetic material.

    Magnetic fields and electrical fields are closely related. Which is why you can create magnets using electricity, known as electromagnets.

    How are magnetic fields measured?

    There are typically two units that are used to describe magnetic fields.

    The Tesla

    Strong magnetic fields are measured by a unit called a tesla. Named after Nikola Tesla, this unit of measurement calculates the magnetic flux density per meter.

    The Gauss

    For smaller magnetic fields, a unit called a gauss is used. One tesla is actually really big. It equals 10,000 gauss.


    To put this into perspective, Earth's magnetic field is about 0.5 gauss. Jupiter's magnetic field is about 12 gauss.

    The Sun's magnetic field is more complicated. It sits at about 1-2 gauss around the poles and can jump to 3,000 gauss in a sunspot.

    If the math ever gets confusing, just plug your numbers into our Magnetic Field Converter.

    Why is magnetic field important?

    We don't realize it, but without the Earth's magnetic field, it would be very difficult for life to exist here.

    Our magnetic field protects us from cosmic and solar radiation. The Sun emits waves of radiation called the Solar Wind. Our magnetic field diverts most of the solar wind away from us.

    It also helps us keep our atmosphere. By contrast, Mars has a weak magnetic field. With no protection, the solar wind stripped most of the Martian atmosphere away millions of years ago.

    What is the formula for magnetic field?

    The magnetic field equation isn't too difficult, granted you have the right information on hand.

    Magnetic field = µ0 · I / 2π (r)


    • The permeability of free space (µ0) is a constant - 4π x 10-7 T·m/A
    • The current magnitude (I) is the strength of the electrical current in Amperes.
    • And the distance (r) means the distance from the magnet in meters.


    In basic terms, the magnitude of a magnetic field is a function of how strong the current is, and it's distance from the magnet.

    How do you convert between similar units?

    To convert magnetic fields, you'll need to know certain ratios.

    The fastest method to get accurate results is with our conversion calculator, but we'll cover a few common conversions below.

    Gauss to Tesla

    One tesla is 10,000 gauss. Divide any unit listed in gauss by 10,000 to get the corresponding tesla unit.

    Tesla = Gauss / 10,000


    Earth's magnetic field is about 0.5 gauss which converts to 0.00005 tesla.

    0.5 gauss / 10,000

    = 0.00005 tesla

    Tesla To Microtesla

    There are 1,000,000 microteslas in one Tesla.

    Microtesla = Tesla x 106

    That means a microtesla is 0.01 gauss.


    Earth's magnetic field converts to about 50 microteslas.

    0.00005 tesla x 106

    = 50 microtesla

    When in doubt use our magnetic field converter. This calculator easily converts to and from Tesla to Gauss and more.

    When were magnetic fields discovered?

    People have studied magnetism for thousands of years. The Chinese first documented their studies of magnets over 2000 years ago.

    Europeans used magnetic compasses on ocean vessels as early as the 12th century.

    In 1600 an English physicist named William Gilbert published a paper called El Magnete.

    He first stated that the Earth behaved like a magnet, and thus, had a magnetic field.

    How is a planet's magnetic field formed?

    The Earth

    The Earth's magnetic field exists because of its liquid, metallic core. Earth has a solid inner core and a liquid outer core.

    The solid inner core is hot, about as hot as the surface of the Sun. And the heat convection causes the outer core to move in convection currents.

    These molten metal currents produce an electrical field that creates our magnetic field.


    Jupiter is made of gas. So, how does it have a magnetic field?

    The further you go beneath the clouds of Jupiter, the hotter it gets and the more pressure builds. With pressure and heat, elements start to act in strange ways.

    Jupiter's make up is almost entirely hydrogen and helium, the two lightest elements.

    Under intense heat and pressure, hydrogen acts like a liquid metal. And that's how Jupiter has such a powerful magnetic field.

    Final thoughts?

    Magnetic fields are part of one of the primary forces in nature, magnetism. Without magnetism, we wouldn't have electricity as we know it.

    They also protect us from space radiation and solar wind. Look around at the desolate landscape of Mars to see the effects of a limited magnetic field.

    Jupiter's magnetic field is so large that it would look as big as the Moon if we could see it in the sky.

    And some scientists think it helps protect the Earth from interstellar radiation.

    Did we forget any questions in our FAQ? Feel free to contact us and let us know what you'd like answered.

    We hope this guide has been helpful to you. Be sure to check out our other calculators for all of your physics and math needs.

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