Yes. There is evidence that some animals, like sea turtles and salmon, have the ability to sense the Earth's magnetic field (although probably not consciously) and to use this sense for navigation.
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Is the Earth a magnet?
In a sense, yes. The Earth is composed of layers having different chemical compositions and different physical properties. The crust of the Earth has some permanent magnetization, and the Earth’s core generates its own magnetic field, sustaining the main part of the field we measure at the surface. So we could say that the Earth is, therefore, a "magnet." But permanent magnetization cannot occur...
Do any mass extinctions correlate with magnetic reversals?
No. There is no evidence of a correlation between mass extinctions and magnetic pole reversals.Earth’s magnetic field and its atmosphere protect us from solar radiation. It’s not clear whether a weak magnetic field during a polarity transition would allow enough solar radiation to reach the Earth's surface that it would cause extinctions. But reversals happen rather frequently--every million years...
How does the Earth's core generate a magnetic field?
The Earth's outer core is in a state of turbulent convection as the result of radioactive heating and chemical differentiation. This sets up a process that is a bit like a naturally occurring electrical generator, where the convective kinetic energy is converted to electrical and magnetic energy. Basically, the motion of the electrically conducting iron in the presence of the Earth's magnetic...
Does the Earth's magnetic field affect human health?
The Earth's magnetic field does not directly affect human health. Humans evolved to live on this planet. High altitude pilots and astronauts can experience higher levels of radiation during magnetic storms, but the hazard is due to the radiation, not the magnetic field itself. Geomagnetism can also impact the electrically based technology that we rely on, but it does not impact people themselves...
Why measure the magnetic field at the Earth's surface? Wouldn't satellites be better suited for space-weather studies?
Satellites and ground-based magnetometers are both important for making measurements of the Earth’s magnetic field. They are not redundant but are instead complementary: Satellites provide good geographical coverage for data collection. Ground-based magnetometers are much less expensive and much easier to install than satellites. An array of magnetometers provides coverage from numerous locations...
What is declination?
At most places on the Earth's surface, the compass doesn't point exactly toward geographic north. The deviation of the compass from true north is an angle called "declination" (or "magnetic declination"). It is a quantity that has been a nuisance to navigators for centuries, especially since it varies with both geographic location and time. It might surprise you to know that at very high latitudes...
How do salmon know where their home is when they return from the ocean?
Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon. Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using smell to find their way back to their home stream. They build their...
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- FAQ
Is the Earth a magnet?
In a sense, yes. The Earth is composed of layers having different chemical compositions and different physical properties. The crust of the Earth has some permanent magnetization, and the Earth’s core generates its own magnetic field, sustaining the main part of the field we measure at the surface. So we could say that the Earth is, therefore, a "magnet." But permanent magnetization cannot occur...
Do any mass extinctions correlate with magnetic reversals?
No. There is no evidence of a correlation between mass extinctions and magnetic pole reversals.Earth’s magnetic field and its atmosphere protect us from solar radiation. It’s not clear whether a weak magnetic field during a polarity transition would allow enough solar radiation to reach the Earth's surface that it would cause extinctions. But reversals happen rather frequently--every million years...
How does the Earth's core generate a magnetic field?
The Earth's outer core is in a state of turbulent convection as the result of radioactive heating and chemical differentiation. This sets up a process that is a bit like a naturally occurring electrical generator, where the convective kinetic energy is converted to electrical and magnetic energy. Basically, the motion of the electrically conducting iron in the presence of the Earth's magnetic...
Does the Earth's magnetic field affect human health?
The Earth's magnetic field does not directly affect human health. Humans evolved to live on this planet. High altitude pilots and astronauts can experience higher levels of radiation during magnetic storms, but the hazard is due to the radiation, not the magnetic field itself. Geomagnetism can also impact the electrically based technology that we rely on, but it does not impact people themselves...
Why measure the magnetic field at the Earth's surface? Wouldn't satellites be better suited for space-weather studies?
Satellites and ground-based magnetometers are both important for making measurements of the Earth’s magnetic field. They are not redundant but are instead complementary: Satellites provide good geographical coverage for data collection. Ground-based magnetometers are much less expensive and much easier to install than satellites. An array of magnetometers provides coverage from numerous locations...
What is declination?
At most places on the Earth's surface, the compass doesn't point exactly toward geographic north. The deviation of the compass from true north is an angle called "declination" (or "magnetic declination"). It is a quantity that has been a nuisance to navigators for centuries, especially since it varies with both geographic location and time. It might surprise you to know that at very high latitudes...
How do salmon know where their home is when they return from the ocean?
Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon. Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using smell to find their way back to their home stream. They build their...
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