- The Crab Nebula is supernova remnant located in the Constellation “ Taurus the Bull”. It was first discovered July 4, 1054. It has been an expanding ball of gas and debris for the last 957 years. Today the bubble is 4.4 lightyears across. New satellite telescopes have been observing the Crab in the X-ray and Gamma Ray wavelengths. Astronomers were surprised that the Crab is still very active. So active they do not have the physics to explain it. There is always more to learn.
- Attachments - Crab Nebula
- In 1758 the Crab Nebula was the first nebula to be cataloged by Charles Messier as “M1”. Today we know that at the center of the nebula is a rotating Neutron Star. The star is called a Pulsar because it has jets of radiation spewing out its magnetic poles that sweep past our field of view 33 times per second. This lighthouse beam coming from this giant gyroscope is one of the most accurate clocks known to man. The pulses are accurate to within 1 millisecond over 75 years.
- Recent X-ray and Gamma Ray images have made the Neutron Star and the opposing jets clearly visible. Also visible is a ring of highly energized particles created by shockwaves emanating from the Neutron Star. Periodically there are enormous flares produced that can be observed at the X-ray and Gamma Ray wavelengths. Astronomers are baffled on how to explain how these outbursts are produced. This review will illustrate how math is used in some of their analysis.
- To get more background on the Crab Nebula request these reviews:
-------------------- #1100 - “ What Created the Crab Nebula”
-------------------- #862 - “Crab Nebula Neutron Star”
------------------- #720 - “ Crab Nebula”
- To see the images at different spectrum wavelengths check out the internet for these space telescopes:
------------------- Spitzer Telescope infrared pictures
------------------- Chandra telescope X-ray pictures
------------------ Fermi telescope Gamma Ray pictures.
- The Neutron Star is 1.4 Solar Mass and 10 kilometers in diameter. It is spinning at 33.085 revolutions per second. The nebula is 4.4 lightyears across and 6,500 lightyears away.
- To explain the enormous flare up of energy astronomers speculate that somehow electrons are getting revved up to over 10^15 electron volts. This is more energy than astronomers have ever observed before. Electrons hurled out of the Pulsar’s core are moving electric charges that generate moving magnetic fields. These electrons traveling near the speed of light slam into strong magnetic fields that exist in the surrounding debris. These collisions push the electron’s energy up to where they emit Gamma Rays. However, the calculations for the magnetic energy that the inner region of the nebula would have to have is 3 to 10 times stronger than the physics would allow.
- There must be more to learn from ol’ M1. The X-ray images show an elliptical ring of high energy particles located some distance from the Neutron star. The ring is elliptical because it is tilted to our point of view. To estimate the diameter we measure the major axis of the ring in the image to be 10 millimeters across. So the radius of the circle is 5 millimeters. The total image is 70 millimeters on a side. The width of the image is calculated to be 5 lightyears across. Using a proportional scaling factor:
------------------------------ 5 / 70 = r / 5 light waves
------------------------------ r = 0.36 light waves
---------------------------- The radius of the ring is 0.36 lightyears.
- The high energy electrons emitted from the Neutron Star are traveling at 95% the speed of light. How long does it take the electrons to smash into the ring?
-------------------------- Time = Distance / Speed
-------------------------- Speed = 95% * 300,000 kilometers per second
-------------------------- Speed = 285,000 km / sec
-------------------------- 1 lightyear = 9.46*10^12 kilometers
--------------------------- Time = 0.36 LY * 9.46*10^12 km / LY / 2.85*10^5 km /sec
-------------------------- Time = 1.195 * 10^7 sec * 1 day / 8.64*10^4
--------------------------- Time = 138 days for the electrons
- When astronomers see the first flash of light from the Pulsar flare they know that to see the shockwave effect on the ring of particles to wait 138 days.
- How much later do the high energy electrons reach the ring after the light waves?
---------------------------- Time = 131 days for the electromagnetic photons
- The electrons reach the ring 7 days after the radiation gets there. What astronomers see is an X-ray radiation that is 100 times brighter than they have ever seen before. Short duration Gamma Rays have energies of greater than 100 million electron volts. Some of these flares last for days. How can they do that?
- Stay tuned an announcement will be made shortly. It must be science if you do not know the answers.
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