The high energy crab

Oct 31, 2011
An image of the Crab Nebula taken by the Hubble Space Telescope. Observations of the Crab in gamma-rays find surprisingly bright emission. Credit: NASA

( -- The Crab Nebula is the remnant of a supernova. Its precursor star exploded in 1054 AD in an event that was recorded by Chinese and (quite probably) Anasazi Indian astronomers. It is called the Crab Nebula because it has many tentacle-like gas filaments extending outward nearly radially. At the center of the explosion is a pulsar, the spinning, super-dense stellar ash often left behind after a supernova explosion. Supernovae play a critical role in the cosmic ecosystem, because they seed space with the elements needed for life, including carbon, oxygen, and nitrogen. All of these elements are made in the precursor stars as a byproduct of nuclear burning; none were present in the early days of the universe.

Although supernovae have been seen since 1054, pulsars were only detected in 1968 thanks to advances in and the fact that pulsars have strong . Pulsars are rapidly spinning (the Crab pulsar spins about 30 times a second) and have strong magnetic fields. Charged particles in this environment are whipped around at nearly the speed of light, and as a result they shine at wavelengths from very low energy radio to very high . Studying this light provides key information about the physical processes underway both in pulsars and supernovae. Surprises from these extreme conditions regularly turn up.

CfA astronomers Nicola Galante, Danny Gibbs, Emmet Thomas, Martin Schroedter, and Trevor Weekes, along with a large team of colleagues, used the VERITAS array of telescopes in Arizona to study the high energy gamma-rays from the . They made two remarkable discoveries: first, they saw the gamma-rays pulsing, just as radiation at shorter wavelengths does. More significantly, they found that these gamma-rays were extremely intense - much brighter than expected from conventional models of pulsar emission. Writing in the latest issue of Science magazine, the scientists conclude that the gamma-rays cannot come from usual pulsar mechanisms like accelerating charged particles. Instead, they suggest the process whereby light is scattered by fast-moving electrons in the outer reaches of the pulsar environment. The new paper adds new insights to the nature of a pulsar's environment, and is a powerful reminder about the surprises nature still has in store.

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User comments : 8

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1 / 5 (4) Oct 31, 2011
Why would hot gas and dust congeale into those tentacles?

5 / 5 (1) Oct 31, 2011
I would appreciate being informed by the introduction what the article is about instead of having ruminated the 10000th time, that the crab nebula has been observed by the chinese and is the remnant of a supernova and ....
1.5 / 5 (8) Oct 31, 2011
Thanks for the story, and thanks Nicola Galante, Danny Gibbs, Emmet Thomas, Martin Schroedter, and Trevor Weekes for pointing out that the gamma rays:

1. Are brighter than expected from conventional models of pulsar emission;

2. Cannot come from usual pulsar mechanisms;

3. Add new insights on a pulsar's environment; and

4. Remind us of the surprises nature still has in store.

In 1960, the Crab Nebula was one of the first puzzling clues I encountered that suggested:

1. Pulsars are not just dead nuclear embers of stars.

2. Pulsars are highly energetic cosmic objects powered by some source of energy other than fusion.

It took 40 years before we finally realized that pulsars are powered by repulsive interactions between neutrons [1,2].

1. 32nd Lunar Sci. Conference, paper #1041 (12-16 Mar 2001)

2. APEIRON J., in press (2011)

With kind regards,
Oliver K. Manuel

5 / 5 (2) Nov 01, 2011
"In 1960, the Crab Nebula was one of the first puzzling clues I encountered that suggested:

1. Pulsars are not just dead nuclear embers of stars.

2. Pulsars are highly energetic cosmic objects powered by some source of energy other than fusion."

In 1960 pulsars were an unknown to science. Pulsars were not ID until 1967 and the pulsar associated with the Crab SNR was not discovered until 1968:


(The word "pulsar" first appeared in print in 1968)

Are you sure of your date?

3 / 5 (4) Nov 01, 2011
Oma-paedo you really are a nutcase. He belives ower sun is basically a Neutron star. He constantly spams his thories everywhery trying to connect his thories with his Neutrino Repulsion Theory!!!

Oh well at least when he is convicted of raping his children his incarceration and castration should stop the spamming.][/url]

3 / 5 (2) Nov 01, 2011
mark, oliver got away with it. he is not out on bond anymore. He agreed to a plea deal and is on sex offender probation for 1 count of attemtpted sodomy mainly due to the statute of limitations having run out on the other charges. It really sickens me as he should spend the rest pf his life in prison or be executed. Repest child molesters who do so over decades to multiple children(his own in this case, making it even worse)deserve no mercy and should be brutally punished.
5 / 5 (1) Nov 01, 2011
It took 40 years before we finally realized that pulsars are powered by repulsive interactions between neutrons [1,2].
No Oliver. First there is no we, its just you with this. Second the radiation from pulsars is powered by two things:

The momentum of the rotating pulsar which is transferred to the ionized gas in space around the pulsar by the strong magnetic field of the pulsar. This transfer is why the pulsation rate decreases over time.

The second source of energy is dependent of the pulsar having a companion star. Matter that is stripped from the companion falls in towards the pulsar thus transferring angular momentum from the companion to the pulsar and thus whipping it up much higher spins than the Crab has.

There is no sign of energy being released by your hypothetical neutron repulsion nor even by neutron decay. And of course if neutron repulsion worked the way you claim then there would be no pulsars, stars, planets or you.

JS MM give it rest.

1 / 5 (1) Nov 02, 2011
i was simply informing mark, ive backed off on oliver quite a bit lately.

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