Jul 31 2007
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Revealing the Veil
No one knows exactly when — maybe it was 5000 years ago, maybe 10,000 — a young star exploded.
It suffered through a fitful life. Born with something like 40 times the mass of the Sun, it led its life a thousand times faster than our more modest star. Hydrogen fused to helium in its core, and then helium to carbon, and carbon to neon… while the vast interplay of light and force drove wave after wave of dense shells of matters off its surface.
Eventually, time ran out. The fuel in the core gone, it collapsed, sending out a fleet of ghostly neutrinos and a shock wave so gigantic that it crushes the human mind to dust. Septillions of tons of matter exploded outward, and a supernova was born.
The gas that was once the core of a sun screamed out at a fraction of light, but something was in the way– the octillions of tons of gas shed earlier by the star, as well as gas and dust left over from its birth just a million or two years before. The two collided, and countless shock waves were generated. The matter surrounding the exploded star was compressed, rammed, and sculpted into thin shells and ribbons. This material, even compressed, is ethereally thin by human standards; seen face-on, the sheets of gas are faint and diffuse, but when they present their edges to us, we see them as sharp filaments, like a soap bubble’s edge. The material glows with the same basic physical principles as a neon sign: sulfur, oxygen, and hydrogen contribute their own unique fingerprints to the eerie luminescence of the gas.
And so we see the aftermath of the cosmic catastrophe that is the Veil Nebula, an arcing structure that has, since the explosion, expanded to a diameter a full six times larger than the Moon in the sky, even though it is something like 36 billion times farther away. It’s located in the constellation of Cygnus, the Swan, high in the summer sky for northern hemisphere observers– but you’ll never see it with the naked eye. Millennia have faded its glory, even though it probably shone almost as bright as the Moon when its light first touched Earth. Now, though, you need a big telescope and dark skies to see it at all.
The image above is newly released from the Hubble Space Telescope, which can resolve fine details in the nebular structure. We understand a huge amount about how stars explode, and what happens in the subsequent centuries, but there is also much we don’t know. Images like this one and the others released with it give us a forensic insight on the event that destroyed an entire star. We learn more about the nuclear fires at its heart, the subsequent alchemy of the expanding debris, and the effects of depositing unimaginable energies into its environment.
But it’s also very pretty. There’s a lot to be said for that as well.
Two things:
One: that was a very poetic description of a stellar event.
Two: with images and data like this, how can the powers that be rationalize shutting down Hubble?
Whoa, I just love this post. The way you describe it is… beautiful.
Ahh… if more people enjoyed astronomy and science at that level, that would be really awesome.
Thanks for making this, Phil, thank you very much.
YinYang0564-
NASA is planning a service mission in September of 2008, so it looks like Ol’ Hubbie is safe for the time being. Anyway, it just has to last until 2013 when the James Webb ’scope is launched.
(Thank you, Wikipedia!)
Also: Anyone else think the James Webb telescope looks like a giant space coffin? With a death ray?
http://en.wikipedia.org/wiki/Image:Jwst_front_view.jpg
The conspiracy nuts will have fun with that, I’m sure.
i’m an astronomy major but stuff like this still gets me.
six times larger…but 36 billion times farther away? surely you jest.
yet a few quick google searches and calculations later, there it is.
Thank you for such a clear and beautiful explanation of how this nebula was formed. I was aware of the basic concept in the past, but now I feel I understand it much better.
So what happens to the shock wave(s)? If space is a near vacuum, why doesn’t a shock wave continue forever? Why aren’t we getting pounded by the shock waves of stellar explosions?
Magnificent writing, Dr. BA,
The Cosmic coffin with Death Ray idea is a great one, I can hardly wait to hear George Noory’s impression…
Where in this picture would the neutron star or perhaps even black hole be? At 40 solar masses, doesn’t the collapsed gravity reach the point of a black hole?
In a less inquisitive note, who needs religion when there is so much beauty in the universe? Stunning objects like this should make us realize how supremely fortunate we are to exist in a fragment of time in the Universe’s history, where a species of primate, is able to reason, build tools to discern the universe around, and view the spectacle that is nature.
That Neil Guy: The short answer, we are. Cosmic rays are high-energy particles that ram into us from all directions (see Wikipedia for more info), one source of these is supernovae. You’ll note that he mentions that the whole thing has expanded over time. At its current scale the concentration of particles is quite low by our standards (I think Phil has a good “Q & BA” section on the various densities involved), and so by the time it expands to meet us, there’s basically nothing left to really notice.
Question for Phil: I never understood what the difference was between gravitational collapse that results in a swartzchild black hole, and the phenomenon described here… If there’s enough gravitation to overcome subnuclear pressures (the ones that keep neutron stars from being black holes), how can it just “throw off” these massive quantities of matter, when it seems like it should all collapse down into a (similarly exciting, but much less visually stunning) black hole.
OK, color me stupid but when you say “6 times bigger than the moon” I’m assuming you mean the apparent angle across as viewed from earth and not actual size because that would be pretty small - smaller than the star was to begin with.
Did I get it or am I missing something?
But Phil, look carefully at that photo again. In particular, look at that bright area on the right hand side of the photo.
Tilt your head 33 degrees to the right, cover your left eye and peel an onion until your right eye starts to water slightly. Then it will become clear - the picture will shine with clarity and you will see that what Hubble has captured is nothing more than the image of… an angel.
If anyone needs me some nice young men in white coats are just coming up the path now…..
That Neil Guy,
I’m not much into astronomy and such, but I’m fairly certain the energy from such shock waves would dissipate following the inverse square law.
Though the energy does continue on forever, it gets distributed evenly over an ever increasing area. By the time it reaches us, it is hard to even detect, let alone be hazard.
After all, the universe is a really big place.
Doesn’t a shock wave need some medium to propagate in?
I have seen it with an 8″ telescope and an OIII filter under a dark sky. It looks very different of course, but in many ways it’s even more awesome to see it yourself with your own eyeball. It looks like a grey twisted tendril of smoke and is one of the coolest things I have ever seen.
I know people who claim to have seen it by holding an OIII filter up to their naked eye under a very dark sky, but I’ve never done it myself.
Awesome post, dude.
One of my favorites.
Oh. My. Pareidoliac. God. That blue bit: It’s Batman’s face, as clear as day.
Pretty.
One patch of awkward wording:
I think the word “speed” is missing. Something about the concept of light speed instead of luminosity. I get it from context, but the wording is awkward.
YinYang0564 said:
> Two: with images and data like this, how can the powers that be rationalize shutting down Hubble?
There are more issues at stake than just the ability to take the pictures. There’s the overall functionality of the Hubble, the final fate of Hubble when it shuts off for good, and the safety concerns for a servicing mission. Fortunately, a servicing mission is currently planned.
CafeenMan, you are right on. As it appears in the sky, compared to how the Moon appears in the sky.
Selina Morse, I see a dragon. Head to the right, wings up flying, tail to the left.
WJM, the medium is the material itself. The shock wave is matter hitting matter in front of it. As high velocity gas and dust overruns the slower gas and dust, the impacts create a shock wave through the dust and gas.
What happens when it runs out of matter to hit, though? A sound wave is limited in how far in the earth’s atmosphere it can propagate upwards — you won’t hear even the loudest gunshot on earth from the surface of the moon — is there a point where the ISM becomes too attenuated for the shock of a big blowup to effectively propagate further? Yes, the shock wave is “hitting matter in front of it”, but only so long as there’s a useful amount of matter in front of it, no? Remember, the Veil stuff is hitting stuff that the Veil star had either previously spewed, or never quite swallowed up during formation. That stuff would be at a greater density than the “vacuum” of interstellar space, wunnit?
As far as the ‘medium’ debate is concerned:
How do shock waves propagate through what we refer to as ‘normal’ atmospheric pressure? True, there are a LOT of gas molecules per cubic centimeter, but if all of the molecules were condensed into a liquid, you would have a cubic centimeter of high vacuum, with a very thin smear of mostly Nitrogen molecules on the bottom. The point is, no matter how dense, or thin the gas, it’s mostly empty space, with a few dots of matter scattered about.
Looking at Earth atmosphere microscopically, there should be no way for a shock wave (sound) to propagate, since it’s mostly vacuum.
I loved the way you wrote that Phil, I am looking forward to your book.
Oooh, pretty nebula!!
The HST team have done a fine job (yet again).
Plus, what a wonderfully impassioned description of the supernova event. Thanks, Phil for another fine article.
Do you happen to know what the different colours in the picture represent (i.e. which filters were in place for the image and what colour was assigned to what wavelength in the picture we see)?
Unless my math is off, there seems to be a mistake in the article.
Paragraph 5: … These shocks, driven by debris moving at 600,000 kilometres per hour, heat the gas to millions of degrees. …
That’s over 7000 times the speed of light! Supernovae are warp field generators!
MattFunke, your math appears off.
Light speed is 1,079,252,848.8 km/hr
http://en.wikipedia.org/wiki/Speed_of_light
600,000 km/hr is 1800 times slower than light speed.
WJM, what is a “shock wave”? It’s the propogation of the interface between high velocity and slower particles. As the shock wave progresses through the material and reaches thinner and thinner regions of space, the wave dissipates. The momentum and energy transfer slows the faster particles and speeds up the slower particles. Some of the faster (higher energy) particles keep going because they don’t hit local dust, and they spread further and further apart as they travel away from the source. The “wave” dissipates because there’s not a local enough collection of interference. But collisions continue to happen until every particle has one (or more) and all the energy is dissipated.
Irishman: MattFunke, your math appears off.
Oops. You’re exactly right. Thanks for the correction. I realized it myself some time afterward… I multiplied where I should have divided. (Always use dimensional analysis!)
[…] Revealing the Veil Star death brought us this incredible image. […]
Indeed, very like a dragon.
The nebula is beautiful! From that description, though, it’s not clear why it’s not just a sphere. Certainly inhomogeneities in the interstellar medium will have some effect, but in fact the Rayleigh-Taylor instability is what leads to the complex shapes that nebulae have. That instability is how a heavier fluid on top of a lighter fluid begins to exchange places, and you can build a little toy to demonstrate it.
I don’t understand: how can this thing be 10,000 years old when according to Genesis the world is only 6,000 years old?
I’m kidding of course.
This is a beautiful image of a truly impressive event, and a great article. Thank you.
Phil, great writing. Stumbled here. Now feeded up. More please.