• On August 28, 1859, astronomers and everyday citizens observed the first impacts of the largest geomagnetic storm ever recorded. The Great Geomagnetic Storm lasted until early September.
     
    A geomagnetic storm is caused by the solar wind interacting with the Earth’s magnetic field. (In fact, a geomagnetic storm is also called a solar storm.) The solar wind is a powerful flow of charged particles (electrons and protons) flowing from instances of solar activity all the way to the edge of the solar system. Solar activities that cause a pulse in the solar wind include sunspots and coronal mass ejections. Usually, pulses from the solar wind take about three days to reach Earth. During the Great Geomagnetic Storm, solar activity was so fierce that particles traveled from the Sun to the Earth in just 18 hours.
     
    The most dramatic and beautiful pieces of evidence from geomagnetic storms are the aurora borealis and aurora australis—the Northern and Southern Lights. Usually, the auroras are concentrated in polar regions. During the Great Geomagnetic Storm, however, the Northern Lights were visible as far south as the islands of Cuba and Hawaii, and the Southern Lights were visible as far north as Brisbane, Queensland, Australia.
  • Term Part of Speech Definition Encyclopedic Entry
    astronomer Noun

    person who studies space and the universe beyond Earth's atmosphere.

    aurora australis Noun

    bright bands of color around the South Pole caused by solar wind and the Earth's magnetic field. Also called the southern lights.

    aurora borealis Noun

    bright bands of color around the North Pole caused by solar wind and the Earth's magnetic field. Also called the northern lights.

    concentrated Adjective

    items gathered closely together in one place.

    coronal mass ejection Noun

    huge burst of solar wind and other charged particles.

    electron Noun

    negatively charged particle in an atom.

    evidence Noun

    data that can be measured, observed, examined, and analyzed to support a conclusion.

    fierce Adjective

    wild or savage.

    impact Noun

    meaning or effect.

    instance Noun

    an occurrence or example of something.

    interact Verb

    to work with or meet.

    magnetic field Noun

    area around and affected by a magnet or charged particle.

    observe Verb

    to watch.

    particle Noun

    small piece of material.

    polar Adjective

    having to do with the North and/or South Pole.

    proton Noun

    positively charged particle in an atom.

    region Noun

    any area on the Earth with one or more common characteristics. Regions are the basic units of geography.

    Encyclopedic Entry: region
    Scandinavia Noun

    region and name for some countries in Northern Europe: Iceland, Norway, Sweden, Finland, and Denmark.

    Siberia Noun

    region of land stretching across Russia from the Ural Mountains to the Pacific Ocean.

    solar storm Noun

    sudden change in the Earth's magnetosphere, caused by the solar wind interacting with the Earth's magnetic field. Also called a geomagnetic storm.

    solar system Noun

    the sun and the planets, asteroids, comets, and other bodies that orbit around it.

    solar wind Noun

    flow of charged particles, mainly protons and electrons, from the sun to the edge of the solar system.

    sunspot Noun

    dark, cooler area on the surface of the sun that can move, change, and disappear over time.

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