Crab Nebula facts for kids
statistic, see tau-a.| Supernova remnant | |
|---|---|
Hubble Space Telescope mosaic image assembled from 24 individual Wide Field and Planetary Camera 2 exposures taken in October 1999, January 2000, and December 2000
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| Observation data: J2000.0 epoch | |
| Right ascension | 05h 34m 31.8s ICRS |
| Declination | +22° 01′ 03″ ICRS |
| Distance | 6500±1600 ly (2000±500 pc) |
| Apparent magnitude (V) | 8.4 |
| Apparent dimensions (V) | 420″ × 290″ |
| Constellation | Taurus |
| Physical characteristics | |
| Radius | ~5.5 ly (~1.7 pc) |
| Absolute magnitude (V) | −3.1±0.5 |
| Notable features | Optical pulsar |
| Designations | Messier 1, NGC 1952, Taurus A, Sh2-244 |
The Crab Nebula (also known as M1, NGC 1952, or Taurus A) is a beautiful cloud of gas and dust in space. It is located in the constellation of Taurus. This nebula is a supernova remnant, which means it is the leftover material from a giant star that exploded.
The explosion that created the Crab Nebula was seen by people on Earth in the year 1054. Astronomers in China and Japan wrote about a "guest star" that appeared in the sky. It was so bright that it could be seen during the day. Today, we know this event was a supernova.
At the very center of the nebula is the Crab Pulsar. This is a neutron star that spins very fast, about 30 times every second. It sends out pulses of radiation, acting like a cosmic lighthouse. The nebula is about 6,500 light-years away from Earth. You cannot see it with just your eyes, but you can see it with binoculars or a telescope.
Contents
History of the Crab Nebula
The story of the Crab Nebula begins almost 1,000 years ago. It is one of the few objects in space that we can connect to a specific event in history.
The Guest Star of 1054
In July 1054, astronomers in China noticed a new, bright star in the sky. They called it a "guest star" because it appeared suddenly. It was visible during the daytime for 23 days. At night, it remained visible for nearly two years before fading away.
Japanese observers and possibly people in the Middle East also recorded this event. Rock paintings in North America made by the Ancestral Puebloans might also show this supernova. For a long time, no one knew what this star was. In the 20th century, scientists realized that the expanding cloud of the Crab Nebula was in the exact same spot as the star of 1054.
Discovery and Naming
Long after the supernova faded, astronomers with telescopes found the nebula again.
- 1731: An English doctor and astronomer named John Bevis discovered the nebula.
- 1758: A French astronomer named Charles Messier found it while looking for a comet. He realized it was not a comet because it did not move. He made it the first object in his famous list, the Messier catalogue, naming it "M1".
- 1844: William Parsons, 3rd Earl of Rosse, looked at the nebula through a large telescope. He made a drawing that looked like a crab with legs. Because of this drawing, it became known as the Crab Nebula.
Physical Features
The Crab Nebula is a giant, expanding cloud. It is full of energy and matter from the exploded star.
Distance and Size
The nebula is located in the Perseus Arm of our Milky Way galaxy. It is about 6,500 light-years away from Earth. This means the light we see today left the nebula 6,500 years ago.
The cloud is about 11 light-years wide. It is expanding outward at a very high speed of about 1,500 kilometers per second (930 miles per second).
What Is It Made Of?
The nebula looks like an oval mass of filaments, which are like threads of gas. These filaments are the remains of the star's outer layers. They contain elements like:
Inside the filaments is a blue glow. This glow comes from electrons moving almost at the speed of light around magnetic fields. This type of light is called synchrotron radiation.
The Star at the Center
The engine that powers the Crab Nebula is a tiny but powerful star at its center.
The Crab Pulsar
When the original massive star exploded, its core collapsed. It became a neutron star. This star is incredibly dense. It has more mass than our Sun, but it is only about 28 to 30 kilometers (17 to 19 miles) wide.
This neutron star is called the Crab Pulsar. It was discovered in 1968. It spins around 30 times every second. As it spins, it shoots out beams of radiation, including radio waves, X-rays, and gamma rays. When these beams sweep past Earth, we see a pulse, just like a lighthouse beam.
A Powerful Engine
The pulsar creates a strong magnetic field and a wind of charged particles. This energy slams into the surrounding gas, creating shock waves. This process lights up the nebula and makes it glow brightly. The Crab Nebula is one of the brightest sources of high-energy radiation in the sky.
Scientific Discoveries
Scientists use the Crab Nebula to learn more about the universe. Because it is so bright and we know exactly where it is, it helps astronomers study other objects.
Learning from Transits
Sometimes, objects in our Solar System pass in front of the Crab Nebula. This is called a transit or occultation.
- The Sun's Corona: In the 1950s and 1960s, scientists watched radio waves from the nebula pass through the Sun's outer atmosphere (corona). This helped them map the density of the Sun's atmosphere.
- Saturn's Moon Titan: In 2003, Saturn's moon Titan passed in front of the nebula. The shadow created by Titan blocked some X-rays. This allowed scientists to measure the thickness of Titan's atmosphere.
Gallery
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Images taken over four months show how the center of the nebula changes.
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An image showing Saturn's moon Titan passing in front of the nebula.
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A video showing the pulsing light of the Crab Pulsar.
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The Crab Nebula seen in different types of light: radio, infrared, visible, ultraviolet, X-ray, and gamma-ray.
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Images from five different space observatories.
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Animation showing the nebula in different wavelengths.
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The Crab Nebula imaged by the James Webb Space Telescope in infrared light.
See also
In Spanish: Nebulosa del Cangrejo para niños
- Lists of nebulae
- List of Messier objects
- Southern Crab Nebula, named because it looks like the Crab Nebula, but seen from the southern part of Earth.
