Question

What are the variations of earth's magnetic field that have occurred with the passage of time??

Answer 1

The geomagnetic field changes on time scales from milliseconds to millions of years. Shorter time scales mostly arise from currents in the ionosphere (ionospheric dynamo region) and magnetosphere, and some changes can be traced to geomagnetic storms or daily variations in currents. Changes over time scales of a year or more mostly reflect changes in the Earth's interior, particularly the iron-rich core.[12]
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.[29]
Data from THEMIS show that the magnetic field, which interacts with the solar wind, is reduced when the magnetic orientation is aligned between Sun and Earth – opposite to the previous hypothesis. During forthcoming solar storms, this could result in blackouts and disruptions in artificial satellites

Answer 2

The Earth works exactly like a magnet.

It also contains a North Pole and South Pole .

The Earth's magnetic field is observed to change with the passage of time .

The polarity of the Earth's Magnetic Field keeps on changing with time.

This phenomenon is called Polarity reversal.

The causes of Polarity reversal are mainly due to changes below the Earth's surface.

Due to tectonic movements and other factors , the core of the Earth is weakening day by day.

Even we are responsible due to the fact that we extract a lot of energy from the Earth in the form of geothermal energy.

Another factor of change is the Continental Drift or the shift in the position of continents over the years.

The magnetic field of the Earth is weakening day by day .

It may become zero after few thousands of years !

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