Orion is a morning constellation right now, high in the sky if you get up early enough. The three stars making the belt are obvious enough, and just below it hangs his dagger*. The middle star in the dagger is not a star, but a star-making gas cloud of mind-numbing size. There is much to see in the vast sprawl of its 5000 cubic light year volume, including young stars, still going through the pangs of birth.
One of these is the strange object called Herbig-Haro 502: a newly-born star shooting twin jets of material, far, far out into the nebula itself. Its beauty is simply breathtaking, as you can see in this spectacular image from Hubble:
[Click to ennebulanate to the giant 3800 x 3800 pixel version.]
Against the background gas of the Orion Nebula, HH 502, as those of us in the know call it, is almost lost — it’s the star just to the left of center wrapped in what looks like pink gauze (the jets are easier to spot in the full-res version). This image is a tiny, tiny fraction of the entire nebula, but the detail is exquisite. You can trace the jets of gas quite a ways. In real terms, the whole object is roughly a light year — 10 trillion km, 6 trillion miles — end to end. Neptune’s orbit would be a razor thin slice of a pixel on this scale.
There’s a lot to see. If you look carefully, you can see arc-shaped features all over the place. These are bow shocks, like the shock wave off the nose of a plane moving faster than sound. That’s usually caused by winds of gas screaming off of stars and slamming into the gas around it. Really elongated ones can be seen, too, and those are associated with the material firing away from the star at HH 502’s center.
Deep inside the Milky Way’s companion galaxy called the Large Magellanic Cloud lies a vast complex of stars, gas, and dust. From our vantage point, 170,000 light years away, we see it as a softly-glowing pinkish brain-shaped cloud studded with stars — a description that grossly underdescribes the tremendous beauty of the newly-released Hubble view of it:
Oh, my. Click it to get a bigger version, or go here to get a 26 Mb 4000×4000 pixel version.
What a staggeringly lovely image! And so much to see. More than you’d expect… but that’s part of a surprise I’ll have for you at the end of this post. Bear with me, it’s worth it.
Until then, let me show you a thing or two…
Herschel is a European space-based astronomical observatory. It launched last year, and the first science papers are now being published. Along with those papers, the European Space Agency released a bunch of way cool pictures.
As usual, I could use up a mole of electrons describing them, but one in particular caught my eye:
Egads! Click it to embiggen.
Tomorrow marks the 20th anniversary of the launch of the Hubble Space Telescope. I spent ten years of my life working on that magnificent machine, from using observations of a supernova for my PhD, all the way to helping test, calibrate, and eventually use STIS, a camera put on Hubble in 1997.
Last year, I published Ten Things You Don’t Know About Hubble, and I don’t think I can really add much to it here. I also have a lot of new readers since then, so I’ll simply repost it now as my tip o’ the dew shield to the world’s most famous observatory.
On April 24, 1990, the Space Shuttle Discovery roared into space, carrying on board a revolution: The Hubble Space Telescope. It was the largest and most sensitive optical-light telescope ever launched into space, and while it suffered initially from a focusing problem, it would soon return some of the most amazing and beautiful astronomical images anyone had ever seen.
Hubble was designed to be periodically upgraded, and even as I write this, astronauts are in the Space Shuttle Atlantis installing two new cameras, fixing two others, and replacing a whole slew of Hubble’s parts. This is the last planned mission, ever, to service the venerable ‘scope, so what better time to talk about it?
Plus, it’s arguably the world’s most famous telescope (it’s probably the only one people know by name), and yet I suspect that there are lots of things about it that might surprise you. So I present to you Ten Things You Don’t Know About the Hubble Space Telescope, part of my Ten Things series. I know, my readers are smart, savvy, exceptionally good-looking, and well-versed in things astronomical. Whenever I do a Ten Things post some goofball always claims they knew all ten. But I am extremely close to being 100% positive that no one who reads this blog will know all ten things here (unless they’ve used Hubble themselves). I have one or two big surprises in this one, including some of my own personal interactions with the great observatory!
I loves me some astronomical nebulae! And the Wide-field Infrared Survey Explorer — WISE — can really deliver:
[Click to emblossom.]
This image shows AFGL 3193 — what looks like a rosebud — a small piece of a very complicated region of gas, dust, and stars in the constellation of Cepheus in the northern sky. This region has star formation, cold and hot dust, and even a supernova remnant (called NGC 7822). This particular part seen by WISE shows a cluster of young stars called Berkeley 59 — the stars colored blue to the right — surrounded by the gas and dust from which they formed. This cluster is less than a million years old, and the massive, hot stars are blasting out radiation that is eating away at the cocoon surrounding them.
In the false-color image from WISE, red shows the coolest dust, blue and cyan warmer material, and green reveals long-chain organic molecules called polycyclic aromatic hydrocarbons, or PAHs. You can see how the PAHs appear to form around the rim of the nebula as the material there is compressed and warmed by the ultraviolet light and solar winds from the young stars. The filaments are testament to the forces tossed around as the stars go through their violent birth process. One of the stars in the cluster is a massive O5 star with dozens of times the mass of the Sun, and blasting out radiation at a rate 100,000 times that of the Sun!
I’m not sure just how big an area this image covers, but it’s roughly a degree across, twice the width of the Moon on the sky. The cluster is located about 3000 light years away, which is good: a lot of those stars will soon (well, in a few million years) explode, and this distance is far enough away that we’ll see a spectacular light show, but won’t wind up hurting us. Phew!
WISE is designed to survey the sky in infrared, literally spinning around and scanning the entire celestial sphere. It doesn’t have a field of view per se; the data come down in a stream and the astronomers on the ground can put them together at any scale they want, a little bit like Google maps. So expect to see lots more images of objects like this one, and you can get the whole list at the WISE gallery.
Image credit: NASA/JPL-Caltech/WISE Team
The European Southern Observatory just released a very pretty picture of the nebula NGC 346. Check this out:
I strongly urge you to click that to ennebulanate to the higher-res version; I had to shrink and compress it quite a bit to fit it here.
The picture is lovely, showing a star-forming region in the Small Magellanic Cloud, a satellite galaxy to our own. The nebula’s about 200 light years across, and 200,000 light years away.
I won’t go into details; you can go to the ESO site for that. But there’s something I want to point out. The sharp wisps you see strewn this way and that inside the gas are due to vast and powerful winds of subatomic particles blowing from the surfaces of massive stars that are newly-born from that very gas. These streams slam into the gas, compressing it across trillions of kilometers, producing storm fronts that are thinner than a laboratory vacuum but are still so voluminous that the mass adds up to many times that of the Sun’s. Added to that is a flood of high-energy ultraviolet light from these massive stars, energy blasting out as they furiously churn out energy in their cores, leading ultimately to their demise in supernovae explosions.
So while you gaze at this nebula and wonder at its beauty, remember that in our Universe, beauty is borne by great violence. If there’s a life lesson in there I’m unaware of it. But it is worth pondering.
Planetary nebulae are too cool.
When a star like the Sun dies, it goes through a series of episodes where it blows off dense winds, vast volumes of gas which expand out from the star in exotic shapes. This is caused by paroxysms in the star’s core; at its advanced age, fusion of one element into another is unstable, and sometimes huge amounts of energy are suddenly dumped into the star’s outer layers. These outer layers respond by swelling and shrinking, and this in turn is reflected in the winds the star blows.
NGC 2371, seen here in a new Hubble Space Telescope picture, is just such a nebula. The winds from the star have slammed into each other, creating the odd puffy shape. As the star sheds its overcoat of material, the hot, dense core is exposed — you can see it as the pinkish-white dot in the center. That color isn’t real; in fact the star, now called a white dwarf, would be bluish or intensely white. But it’s hot, no doubt: it’s over 130,000 degrees Celsius — and that’s not even the hottest one known, which is well over 200,000 degrees!
At that temperature, the star floods the gas with ultraviolet light, which ionizes the material and makes it glow in the same way as a neon sign. In this particular image, sulfur and nitrogen glow red, hydrogen is green, and oxygen is blue. The colors aren’t real; they were just chosen for aesthetics. In general, hydrogen is reddish and oxygen is green.
I was intrigued by the two pink stubs you can in the nebula, on opposite sides of the central star. Those are called FLIERs, for Fast Low-Ionization Emission Regions (I have details on what they are at that link). Their exact formation mechanism isn’t well-understood, but they always appear like that, on opposite sides of the star, so some symmetric shaping force is at work.
I had to laugh when I saw them; they looked like the electrical studs in the neck of the classic Frankenstein’s monster. Too bad I don’t get to name nebulae! I guess, though, after a second look the studs are too high. They look like ears, maybe, or antennae. There was a robot in an old movie or a book cover; I can’t remember, but it had little antennae sticking out of its head just like this. Anyone remember what I’m talking about? Stuff like that makes me crazy when I can’t remember it. Like an itch you can’t scratch.
Anyway, if you like planetary nebulae, then search the blog here for more; I’ve written about them quite bit, since I studied them for both my Masters and PhD. The Hubble website has dozens and dozens of them, too.