This gorgeous, classic view of the Crab Nebula is actually a composite of 24 images. Colors indicate the different elements expelled when the star that created the nebula went supernova in 1054. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly-ionized sulfur, and red indicates doubly-ionized oxygen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula's eerie interior bluish glow.

Image by NASA, ESA, J. Hester and A. Loll (Arizona State University)

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    On July 4, 1054, a supernova (SN 1054) was observed by astronomers and stargazers across the Northern Hemisphere, and possibly Australia. Its remnant, the Crab Nebula, is among the most-studied objects outside our solar system.
     
    A supernova is one of the most explosive events in the universe. A supernova occurs when a massive star runs out of nuclear fuel (mostly hydrogen and helium). The core of the star collapses, violently ejecting its outer envelope of material into space in a huge shock wave. These blast materials are the filaments still visible as the Crab Nebula. 
     
    The star that went supernova in 1054 was so massive that it left only a rapidly rotating ball of neutrons called a pulsar. The Crab Pulsar is only about 20 kilometers (12 miles) in diameter, but has a mass greater than the Sun! The Crab Pulsar pulses, or spins, about 30 times a second.
     
    SN 1054 was visible as a bright, glowing star for about two years! Astronomers in China, Japan, and what is today Iraq recorded the event. Some historians think that petroglyphs left by Ancestral Puebloans may also have recorded SN 1054. Other historians think the oral tradition of Aboriginal Australians may also refer to SN 1054.
  • Term Part of Speech Definition Encyclopedic Entry
    Aboriginal Australian Noun

    people and culture native to Australia and its surrounding islands. Also called Aborigine.

    Ancestral Puebloans Plural Noun

    (1200 BCE-1300 CE) people and culture native to what is now the southwestern United States. Also called Anasazi.

    astronomer Noun

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

    collapse Verb

    to fall apart completely.

    core Noun

    the extremely hot center of Earth, another planet, or a star.

    Encyclopedic Entry: core
    diameter Noun

    width of a circle.

    eject Verb

    to get rid of or throw out.

    envelope Noun

    material found in a roughly spherical shape around a star.

    filament Noun

    very thin fiber or thread-like structure.

    mass Noun

    measure of the amount of matter in a physical object.

    massive Adjective

    very large or heavy.

    nebula Noun

    cloud of gas and dust in space.

    neutron Noun

    particle in an atom having no electrical charge.

    Northern Hemisphere Noun

    half of the Earth between the North Pole and the Equator.

    observe Verb

    to watch.

    oral tradition Noun

    history, characteristics, and mythology of a culture transmitted through vocal, not written, methods.

    petroglyph Noun

    carving or drawing on rock.

    pulsar Noun

    rapidly spinning neutron star that emits beams (pulses) of radiation.

    rapidly Adverb

    fast.

    record Verb

    to preserve observations with notes, drawings, photographs, audio or video recordings.

    refer Verb

    to direct attention to something.

    remnant Noun

    something that is left over.

    shock wave Noun

    moving, measurable change in pressure and density of a material.

    solar system Noun

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

    star Noun

    large ball of gas and plasma that radiates energy through nuclear fusion, such as the sun.

    supernova Noun

    sudden, violent explosion of a massive star.

    telescope Noun

    scientific instrument that uses mirrors to view distant objects.

    universe Noun

    all known matter, energy, and space.

    violent Noun

    strong, destructive force.

    visible Adjective

    able to be seen.