Facts about Magnetism
- 08
Homing pigeons possess magnetite crystals in their beaks that detect magnetic field variations as small as 5 nanoteslas, enabling navigation across hundreds of kilometers during migration.
- 07
In 1820, Hans Christian Ørsted discovered that electric current flowing through a wire generates a circular magnetic field around it, establishing the fundamental connection between electricity and magnetism.
- 06
MRI machines use superconducting magnets cooled to minus 269 degrees Celsius that generate 1.5 to 3 tesla magnetic fields, strong enough to align hydrogen nuclei in human tissue for medical imaging.
- 05
Permanent magnets retain their magnetism because electrons orbiting atoms in iron, cobalt, and nickel spin in the same direction, creating aligned atomic magnetic fields that reinforce each other.
- 04
Sunspots, dark regions on the Sun's surface caused by intense magnetic fields of 4,000 gauss, follow an 11-year cycle called the solar cycle discovered by Heinrich Schwabe in 1844.
- 03
A rotating neutron star called a pulsar generates magnetic fields exceeding 10 trillion times stronger than Earth's, dense enough to strip electrons from atoms at considerable distances.
- 02
Iron oxide nanoparticles in magnetotactic bacteria align with Earth's magnetic field, allowing them to navigate aquatic environments using internal magnetic compasses discovered by Richard Blakemore in 1975.
- 01
The Earth's magnetic field strength averages 25 to 65 microteslas, reversing its poles approximately every 200,000 to 300,000 years based on geological evidence.