Breaking Down The Crab Nebula

M1, also known as the Crab Nebula, has been observed for centuries. Early drawings show how the nebula appeared in the sky in the early 1800s and modern telescopes like the Hubble and Chandra X-ray Observatory, have taken us deep into the clouds of M1 to see its pulsar star. The Crab Nebula is located 6,500 light-years from Earth and is located in the constellation Taurus. Its six-light-year-wide and at its center, a pulsating star rotates once every 33 milliseconds giving off beams of radio and gamma rays. The pulsar star has the mass of 1.4 suns but is compacted down to the size of a large city, like the size of Manhattan.

Composite image of the Crab Nebula

A new multi-wavelength image of the Crab Nebula with data from radio waves to X-rays

The Discovery

The Crab Nebula was first noticed in 1054 A.D. by Chinese astronomers who called it a “guest star” visible even in the daytime. This event may have been also observed by Native Americans. After that, many astronomers have observed the nebula:

  • John Bevis in 1731 when it was first recognized as an astronomical object with a historical supernova explosion.
  • Charles Messier in 1758, when he cataloged it as M1 (Messier 1) when he mistook it for Halley’s Comet. This observation led him to create a catalog of celestial objects, not to be mistaken as comets.
  • William Parson in 1844 sketched the nebula and gave it its now-current name because it somewhat resembled a crab.
  • In 1967, British astronomer graduate student, Jocelyn Bell, discovered that at the center of the nebula was pulsar star. The Neutron star spins and emits pulses of radiation 30 times per second.

In the 1940s, with the use of the 100-inch Hooker Telescope at Mt. Wilson, California, it was computed back to the time when the Crab Nebula began expanding. It was calculated its expansion would have started around 1054 A.D., thus linking the supernova to its explosion viewed by the Chinese.

The Crab Nebula is the after-effect of a stellar explosion. A star that produced a supernova left behind the supernova remnant, like a splash of gases and elements from the outer layers of the star expanding outwards. Despite its explosion happening way back in 1054 A.D., the Crab Nebula is considered a young supernova remnant.

Chandra, Spitzer, and Hubble

The Crab Nebula has been observed with many telescopes. Each gives us a new insight into what is pass the dense gases and the bright light from the supernova.

  • In 1999 the Chandra X-Ray Observatory “revealed features in the Crab never seen before, including a bright ring of high-energy particles around the heart of the nebula.”
    X-ray image of the Crab Nebula by Chandra X-Ray Observatory

    Credit: NASA/CXC/SAO

  • In 2002, by coordinating Chandra and the Hubble Space Telescope, observations over almost a year created the first moving images, revealing the action surrounding the pulsating stat like knots that brighten and fade, outbursts, jitter, and expansion of clouds and particles.

  • In 2006, with the new launch of the Spitzer Space Telescope, the first composite of the Crab Nebula was made.
Composite image of the Crab Nebula

Chandra: X-ray in Blue-Purple; Hubble: Optical/ visible light in Green; and Spitzer: Infrared in Red. Credit: X-ray: NASA/CXC/ASU/J.Hester et al.; Optical: NASA/ESA/ASU/J.Hester & A.Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R.Gehrz.

  • In 2017, a highly detailed composite image of the Crab Nebula was created using data spanning nearly the entire electromagnetic spectrum. “Radio waves from the Karl G. Jansky Very Large Array (red), Hubble optical data (green), infrared data from Spitzer (yellow), and X-ray data from XMM-Newton (blue) and Chandra (purple) produced a spectacular new image of the Crab.
high definition composite image of the Crab nebula across various electromagnetic wavelengths

X-rays from Chandra reveal the structure and behavior of the high-energy particles being spewed from the Crab’s central pulsar

More observations have shown the wave-like rings expanding outward from the pulsar star. in 2002 NASA also mention theta through Multiple observations made over several months with NASA’s Chandra X-ray Observatory and the Hubble Space Telescope captured the spectacle of matter and antimatter propelled to near the speed of light by the Crab pulsar.

Most recently in 2018, Another composite image of the pulsar. “The extent of the X-ray image is smaller than the others because extremely energetic electrons emitting X-rays radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light.

new composite of the Crab Nebula with Chandra, Hubble and Apitzer.

A new composite of the Crab Nebula with Chandra (blue and white), Hubble (purple), and Spitzer (pink).

New studies and findings ad to the nearly two decades astronomers have been observing the Crab Nebula using Chandra and other telescopes.

Resources for Educators

  1. The crab Nebula video by ScienceMagazine
  2. M1 – Crab Nebula by Deep Sky Videos
  3. NASA Space Place: Nebulae
  4. NASA: A Crab Walks Through Time
  5. Chandra X-Ray Observatory