Yeah the wording is awkward; the supernova isn’t some sort of force of nature separate from the star that came and ripped it apart, it was the star ripping itself apart.
These are some of the first images we’ve probably inside the after effects due to the nature of the scope.
> “Shattered” seems like an odd way of describing it
Would love for an astrophysicist to pine in. But my understanding is supernovae are usually balanced enough to squeeze their stars' cores. This appears to have been unbalanced such that the core was "broken" instead of uniformly compressed.
> There are also several light echoes visible in this image, most notably in the bottom right corner. This is where light from the star’s long-ago explosion has reached, and is warming distant dust, which is glowing as it cools down.
I'm looking at older pics of Cassiopeia A from the Hubble telescope, and it looks substantially different. How much time needs to pass before a supernova is visibly different? My instinct was that something like this would change over thousands of millions of years, but I'm guessing that's wrong
How quickly do the (damaging to nearby solar systems etc) effects of a supernova propagate through space, in relation to the speed of light?
Or, to put it another way, could we detect the damaging effects of a nearby supernova expanding towards us before those effects actually hit us? And if so, by what factor?
The radiation propagates at light speed, but the harmless neutrinos reach us a few hours before the potentially dangerous X-rays and gamma rays. A supernova would have to be within roughly 160 light years to be damaging to Earth.
> but the harmless neutrinos reach us a few hours before the potentially dangerous X-rays and gamma rays.
Huh? Presumably the electromagnetic radiation travels at the speed of light, and neutrinos travel more slowly; so the neutrinos arrive after the dangerous rays, not before.
They say the supernova happened 350 years ago; and that "Baby Cas A" is 170 light-years behind Cas A. So the echo "caught up" with light coming our way about 340 years ago; that is, the echo consists of light that was emitted just 10 years after the explosion.
Have I got that right?
[Edit] The "echo" isn't really a reflection; it's emission from a gas-cloud heated by the original explosion, as it cools down. So it's not really reflected light from the original event.
If you tell me about a supernova that "absolutely shattered" a star, you better be talking about a pair instability supernova or I'm going to be disappointed. I got excited thinking maybe they'd observed one.
Readit News
> The expanding cloud of material left over from the supernova now appears approximately 10 light-years (3 pc) across from Earth's perspective
https://en.wikipedia.org/wiki/Cassiopeia_A
[1] https://en.wikipedia.org/wiki/Zombie_star
[2] https://iopscience.iop.org/article/10.3847/1538-4357/ac3bbd/...
Is this noteworthy because we’ve seen it, rather than that it exists? How many novae cores have we imaged before?
These are some of the first images we’ve probably inside the after effects due to the nature of the scope.
The others usually retain their core, either as a neutron star or the final collapse to a black hole.
Would love for an astrophysicist to pine in. But my understanding is supernovae are usually balanced enough to squeeze their stars' cores. This appears to have been unbalanced such that the core was "broken" instead of uniformly compressed.
> There are also several light echoes visible in this image, most notably in the bottom right corner. This is where light from the star’s long-ago explosion has reached, and is warming distant dust, which is glowing as it cools down.
Or, to put it another way, could we detect the damaging effects of a nearby supernova expanding towards us before those effects actually hit us? And if so, by what factor?
https://news.fnal.gov/2019/03/waiting-for-neutrinos/
https://earthsky.org/astronomy-essentials/safe-distance-from...
Huh? Presumably the electromagnetic radiation travels at the speed of light, and neutrinos travel more slowly; so the neutrinos arrive after the dangerous rays, not before.
Deleted Comment
They say the supernova happened 350 years ago; and that "Baby Cas A" is 170 light-years behind Cas A. So the echo "caught up" with light coming our way about 340 years ago; that is, the echo consists of light that was emitted just 10 years after the explosion.
Have I got that right?
[Edit] The "echo" isn't really a reflection; it's emission from a gas-cloud heated by the original explosion, as it cools down. So it's not really reflected light from the original event.
https://en.wikipedia.org/wiki/Pair-instability_supernova