Explanation: Supernova remnant Cassiopeia A (Cass A) is a comfortable 11,000 light-years away. Light from the Cass A supernova, the death explosion of a massive star, first reached Earth just 330 years ago. The expanding debris cloud spans about 15 light-years in this composite X-ray/optical image, while the bright source near the center is a neutron star (inset illustration) the incredibly dense, collapsed remains of the stellar core. Still hot enough to emit X-rays, Cass A's neutron star is cooling. In fact, 10 years of observations with the orbiting Chandra X-ray observatory find that the neutron star is cooling rapidly, so rapidly that researchers suspect a large part of the neutron star's core is forming a frictionless neutron superfluid. The Chandra results represent the first observational evidence for this bizarre state of matter.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Neutron stars contain the densest known matter that is directly observable. One teaspoon of neutron star material weighs six billion tons. The pressure in the star's core is so high that most of the charged particles, electrons and protons, merge resulting in a star composed mostly of uncharged particles called neutrons.
Hmm... Six Billion tons per teaspoon. For containing no calories, that's a lot of weight If it were possible to drop a teaspoonful on the earth, i wonder how far it would sink in?
For comparison, The Burj Khalifa, in Dubai, was constructed from 110,000 tons of concrete and 55,000 tons of steele.
At that weight, it would take 36,363.6363.... Dubai towers to be compressed to the size of a teaspoon to equal the
weight of a teaspoon of Neutron Star material
If the light from supernova Cassiopeia A just reached the earth 330 years ago, that means we are viewing the nova today when it was 330 years old. How did it get to be the supposedly 15 light years across in those 330 years? Warp speed explosion? Something is apparently wrong with these figures or the idea that nothing can surpass the speed of light. Norm
ny1b@toasst.net wrote:If the light from supernova Cassiopeia A just reached the earth 330 years ago, that means we are viewing the nova today when it was 330 years old. How did it get to be the supposedly 15 light years across in those 330 years? Warp speed explosion? Something is apparently wrong with these figures or the idea that nothing can surpass the speed of light. Norm
You'll notice that it is not 330 LY across; but 15 LY across. So; no, it is not expanding faster than the speed of light.
For the expanding shock wave to reach a diameter of 15 ly (radius 7.5 ly) in 330 years, it would have to be moving at a rate of only 2.27% of the speed of light, or ~6,800 kps. Fast, but nowhere close to c.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Beyond wrote:Hmm... Six Billion tons per teaspoon. For containing no calories, that's a lot of weight :!: If it were possible to drop a teaspoonful on the earth, i wonder how far it would sink in?
It would fall to the center of the Earth and continue a good bit of the way back through, then fall back, and oscillate that way until it sat at the center. A lot of gravitational energy would be released kinetically, as it would basically be in free fall- billions of tons moving through crust, mantle, and core at a high speed.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Beyond wrote:
Hmm... Six Billion tons per teaspoon. For containing no calories, that's a lot of weight If it were possible to drop a teaspoonful on the earth, i wonder how far it would sink in?
It would fall to the center of the Earth and continue a good bit of the way back through, then fall back, and oscillate that way until it sat at the center. A lot of gravitational energy would be released kinetically, as it would basically be in free fall- billions of tons moving through crust, mantle, and core at a high speed.
Of course a teaspoon of neutrons without tremendous gravitational forces holding it together
(against fermion quantum forces) would represent an enormous and highly unstable nuclei. KABOOM
so what happens to the cooled down blob of neutrons left over if you keep going? does it just sit there in space as a blob or also disapate into nothing? what would this cooled down core of neutrons look like and feel like if approached?
JuanAustin wrote:so what happens to the cooled down blob of neutrons left over if you keep going? does it just sit there in space as a blob or also disapate into nothing? what would this cooled down core of neutrons look like and feel like if approached?
An noted by Art, neutronium (using the term casually) can't really exist at all in isolated teaspoon quantities outside a neutron star or other high pressure environment. A neutron star has a huge mass, and consequently a huge gravitational field to hold the dense matter together. A teaspoon-sized quantity of neutronium won't have enough self-gravity to hold itself together against the internal repulsive forces of the neutron fluid it is made of. It would dissipate extremely rapidly at the low pressures found outside the core of a neutron star.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
JuanAustin wrote:
so what happens to the cooled down blob of neutrons left over if you keep going? does it just sit there in space as a blob or also disapate into nothing? what would this cooled down core of neutrons look like and feel like if approached?
A Dried Poblano Pod
(Will act like a superfluid in your intestines.)
starfalcon2 wrote:
do you believe that this star has an organized magnetic field?...is it spinning rapidly, c/s?
There is no observed pulsar.
Unlike the type II Crab Supernova which was extremely bright when observed in 1054 AD and which left behind the Crab Pulsar, Cas A was a type IIb supernova that went unobserved on earth because it had previously ejected much of its outer layers and was well cloaked by these layers when it finally exploded circa 1700 AD. It is possible, I guess, that Cas A had also ejected much of its angular momentum and its magnetic field along with its outer layers. But that is just a guess on my part.
If light from Cass A only reached us 330 years ago, then Cass A must be 330 light years away, not the 11,000 light years that was stated. If Cass A is actually 11,000 lights years away, then don't you mean that the supernova was only observed 330 years ago? It has to be one or the other. Looks like a typographical error to me?
We seem to have some variation of this conversation every time both light years and a time interval here on Earth are mentioned together. Look at it this way...
The light from a supernova explosion that took place 11,330 years ago our time (very roughly) reached us here on Earth 330 years ago because the explosion took place 11,000 (very roughly) light years away.
The usual advice is to ignore the time something happened way over there and just think in local Earth time. The supernova happened (in our frame of reference) 330 years ago. Period.
rstevenson wrote:We seem to have some variation of this conversation every time both light years and a time interval here on Earth are mentioned together. Look at it this way...
The light from a supernova explosion that took place 11,330 years ago our time (very roughly) reached us here on Earth 330 years ago because the explosion took place 11,000 (very roughly) light years away.
The usual advice is to ignore the time something happened way over there and just think in local Earth time. The supernova happened (in our frame of reference) 330 years ago. Period.
Rob
Rob,
Of course you are correct. Stupid me! The real culprit in this context has to be the genius who coined the term "light year" to mean a distance in the first place. Do you know who it was?
Cooling Neutron Star
Beautiful! I was amazed at how heavy the material in the neutron star was! 
If it were possible to drop a teaspoonful on the earth, i wonder how far it would sink in?
