Every now again I get surprised by a photo, showing me something I didn’t know about. And I love it even more when that surprise is from an object I thought I knew!
So check out this incredible image of the nearby galaxy Centaurus A, a nearby galaxy harboring a whole slew of surprises:
[Click to galactinate, or get the 4000 x 4000 pixel version, or, if you're feeling frisky, cram this onto your hard drive: an image that's 8500 x 8400 pixels and 29 Mb in size! And trust me: you want to.]
Isn’t that stunning? This picture was taken by the MPG/ESO 2.2 meter telescope in Chile, and once you get over its beauty you’ll realize this galaxy is, frankly, seriously messed up.
Cen A is about 12 million light years away and has roughly the same mass as our Milky Way, containing a few hundred billion stars. The underlying glow of those stars is what makes that round background fuzz in the image, and takes on the familiar elliptical shape of many such galaxies. [Note: All the individual stars you see here are in our on galaxy, since we're inside the Milky Way looking out to Cen A. Also, the little circles next to bright stars are reflections inside the camera itself, and aren't real.]
But check out that wide swath of dark stuff across the middle! That blocks the light from stars behind it, so it’s a cold certainty that’s a dust lane: a thick, flat disk of complex molecules commonly seen in galaxies. But… it’s commonly seen in spiral galaxies like ours, not elliptical ones like Cen A. So something’s weird right off the bat. And note how the ends of the disk seem bent in opposite directions; on the right it’s bent down, and on the left it’s bent up.
Most likely, this is because Cen A ate another galaxy. Literally: a galaxy collided with it in the recent past — well, like in the past few dozen million years — and that galaxy was probably more like our own, rich with dust. As it was absorbed, the dust was stripped from it and settled into that disk. The warping at the ends is a gravitational effect, most likely a distortion from the collision itself. We see it in other galaxies that have nearby companions.
When you observe Cen A using a radio telescope it gets weirder: two huge jets of material are being shot out of the core. The image here shows those jets (click to embiggen). Cen A is a very strong emitter of radio waves; in fact that’s why it’s called Cen A: the brightest radio source in the constellation of Centaurus.
The source of those jets is a gigantic black hole in the core of the galaxy. Read More
After having recently posted an interesting picture of the results of star formation in a nearby galaxy, here’s another example, but far closer: an incredibly detailed image of the heart of the Omega Nebula, where stars are being born from huge clouds of gas and dust:
[Click to ennebulenate, or grab an even bigger version.]
This image was taken using the 8.2 meter Antu telescope, one of four making up the European Southern Observatory’s Very Large Telescope in Chile. What you’re seeing here is the central region of a much larger complex of gas and dust located about 6500 light years away toward the center of our galaxy. The whole thing is about 20 light years across, and perhaps as many as 1000 stars are in the process of being born or were recently formed there.
The red color is due to the presence of warm hydrogen gas, the basic building material of stars. It’s being lit up and is glowing due to very young, massive and hot stars — the alpha dogs, if you will — flooding the nebula with ultraviolet light. The dark material is actually dust, which is opaque in visible light, so it blocks the glow from material behind it.
That dust really caught my eye: some of it is not shapeless and random, but has been sculpted into very long, very thin wisps and tendrils. Most of these are parallel, which is a big clue to what causes them. They are most likely being shaped this way by shock waves; supersonic material blasted out from those same young, hot stars. These powerful stellar winds of subatomic material race out and slam into the surrounding material, compressing it. Waves from various stars can also collide, creating very thin streamers like this. Some are so narrow they’re barely resolved in the picture at all.
It’s been a while since I’ve done a Monday spiral, so here’s a great example of one: the nearby beauty M96.
[Click to oooh-and-ahhhhhenate.]
There’s some nifty stuff here. M96 is about 36 million light years away — relatively close by, for a big galaxy — and is part of a small group of galaxies called (can you guess?) the M96 Group. This is a small collection of a dozen or so galaxies, much like the small group of galaxies to which we belong, called (can you guess that one?) the Local Group. M96 is about the same size as our galaxy, too: roughly 100,000 light years across.
The spiral shape is not as symmetric as usually seen in these types of galaxies, and that’s almost certainly due to gravitational interactions with the other galaxies in the group (which are spread out enough not to be seen in this close-up). You can see lots of dark dust swirling around the center of the galaxy, blocking the light from stars behind it. You can see more on the right than on the left, indicating the right side of this galaxy is the side of the galaxy nearer to us. But that top looping arm is way out of proportion to the other side of the galaxy, so it’s probably been tugged out due to the other galaxies in the group. You can see clumpy regions of blue along its length; that’s where stars are being born, blasting out lots of ultraviolet light and causing the surrounding gas to glow.
I think my favorite part of this picture, though, is the reddish edge-on spiral galaxy located in the upper left, almost perfectly aligned with the spiral arm of M96! This is certainly a coincidence; the edge-on galaxy is probably much farther away. The red tinge to it supports that idea; dust in the arm of M96 would absorb bluer light from the more distant galaxy, letting the red light through.
Measuring its size off my screen, I get that it’s about 1/5th the length of M96. If it’s the same size physically as M96, then it’s probably 5 or so times farther away, maybe 150 – 200 million light years off. That’s actually a pretty good distance away. Yet in this image details can still be seen; that’s the advantage of using the colossal 8-meter mirror on the Very Large Telescope! You can still get a pretty clear picture of fantastically distant objects, even when they’re partially obscured by foreground objects.
And you get a gorgeous picture out of it, too.
Image credit: ESO/Oleg Maliy
When I first saw this picture of NGC 2100, I thought it was a globular cluster. But I was wrong. That happens sometimes. Still, it’s worth it to see such a magnificent photo:
Yegads! What a shot! [Click to enstellarnate.]
Globular clusters are tightly packed collections of thousands of stars in a roughly spherical shape (hence their name), and are generally very old. But upon second glance, the stars of NGC 2100 in this image didn’t look quite right to me. There didn’t appear to be enough, for one thing, and though they’re highly concentrated in the center, the distribution around the core seemed off somehow.
Turns out that’s correct. Read More
[I suppose this post has a PG-13 rating. Not for language or nudity, but for what may be a (humorously) disturbing image for some folks. Be ye fairly warned, says I.]
So the European Southern Observatory took the Very Large Telescope, pointed it at NGC 1929 — a cluster of stars 180,000 light years away in the Large Magellanic Cloud — and got this amazing picture:
[Click to ennebulenate, or grab the huger 1780 x 1780 pixel version.]
I was all set to talk about how this huge bubble — over 300 light years across! — is being blown into the gas surrounding the cluster by the combined mighty winds of the stars inside it, young massive stars that live short, violent lives that end in short, violent deaths, and how this will compress the gas further and induce even more star formation, but how in the meantime they’re flooding the gas with powerful ultraviolet radiation that’s lighting up the gas precisely like a neon sign, and how amazingly detailed this image is despite the cluster and gas being in another galaxy at a distance of nearly 2 quintillion kilometers…
[Update: I originally had called this the Very Large Survey Telescope, but have learned it's actually the VLT (for Very Large Telescope) Survey Telescope. I've corrected this in the title and below. I like my less-redundant name for it better, but it's best to be accurate.]
The European Southern Observatory is an agency that governs some of the best telescopes on the planet, and they just added a new eye on the sky: the VLTe Survey Telescope (VST), a 2.6 meter ‘scope in Chile. There are lots of telescopes of similar size dotting our planet, but what makes this one special is its huge field of view — a solid one degree across, twice the diameter of the Moon on the sky – and the resolution of the camera: a terrifying 268 megapixels!
When you put that together, you get some dazzling pictures, like this one of the globular cluster Omega Centauri:
[Click to englobulenate to a 4000 x 4000 pixel 13 MB image, or grab yourself the internet-choking 14,540 x 14,540 pixel 280 MB version.]
Omega Cen is one of the largest globular clusters of the 150 or so orbiting the Milky Way galaxy, a collection of hundreds of thousands or even millions of stars all orbiting the cluster center willy-nilly like bees swarming around a hive. Telescopes like the VST will allow astronomers to survey these clusters quickly and deeply, which is important because it’s sometimes difficult to know what stars are in the cluster and which happen to be in the background or foreground. You have to get a good census of cluster membership before moving on to studying how old the stars are, what they’re made of, and how they behave. Since globulars are among the oldest objects in the Universe and are tied with galaxy formation, understanding them leads to understanding a great deal more.
VST also took this spectacular picture of the star-forming region M17, also known as the Omega nebula:
The European Southern Observatory’s monster 8-meter Very Large Telescope observatory is silhouetted against the galaxy itself — and beyond — in this stunning vista of the high Atacama desert of Chile:
[Click to southernhemispherenate.]
What a breathtaking panorama! It’s dominated by the Milky Way Galaxy, hanging low near the horizon. We live inside the disk of our galaxy, so we see it from the inside out. It makes a thick line across the sky, the central hub bulging out in the middle. Dust chokes the interstellar view, creating dark lanes that block the light from stars behind them.
On the left you can see the two companion dwarf galaxies to our own: the Large and Small Magellanic Clouds. They apparently hang side-by-side in the sky, but are separated by over 40,000 light years… and are removed from us by distances of 160,000 and 200,000 light years, respectively.
And on the right is our eye on the sky, Unit Telescope 1 of the VLT — and that’s only one of four of the giant 8 meter telescopes in operation. I like the imagery here: the telescope at one end, distant galaxies on the other, and bridging them like a cosmic rainbow is our home galaxy itself.
You may make your own metaphor here, but the one I choose is obvious. You might even say this post is entitled to it.
[Edited to add: After writing this, but before posting it, I found that APOD had a very similar picture to this one. Funny coincidence!]
Image credit: ESO/Y. Beletsky
I’m such a sucker for emission nebulae, the sites of intense star formation. Part of that is because I spent years researching other types of gaseous clouds, but also because they’re just so darn pretty, like this shot of NGC 371:
[Click to ennebulanate, or get the 2000 x 2000 pixel version).]
NGC 371 is in the Small Magellanic Cloud, a companion galaxy to our Milky Way. That puts it at a distance of about 200,000 light years, or 2 quintillion (2,000,000,000,000,000,000) kilometers.
I know I’ve been posting a lot of astropr0n lately, but there’s just been so much cool stuff the past few days (and there’s more to come)! The European Space Agency just threw their hat into the ring with this crazy cool image of a young star blowing its stack:
[Click it to ennebulanate, or grab yourself some megasized 2100 x 2100 pixel action.]
I love this image! It shows the havoc caused by young stars as they spew out material at speed upwards of a million kilometers per hour. What you’re seeing is actually a small part of a star-forming region surrounding the star R Corona Australis, a nearby 550 light years away. It’s a densely packed cloud of thick dust and gas, completely hiding the stars inside and behind it. It’s not terribly big, only a couple of light years across — compare that to the Orion Nebula, which is 20 light years across (and that’s only the visible portion; it’s part of a dark cloud that’s much larger). Or the Tarantula nebula, which I posted about yesterday, which is a thousand light years across!
Even though it’s small, it’s the birthplace of many stars. Two such stars reveal their presence here; not by their light, but by blowing out long streamers of matter called jets. Read More
I do so love time-lapse animations, and this one is particularly nice: it shows four of the ALMA microwave antennas in Chile as they scan the night sky, while the starry vault rotates around them. [Make sure you set the resolution to 720 and make this full screen; it's really nice.]
The video starts at moonset, and ends with an amazing view of the the vast central bulge and disk of the Milky Way looming over the ‘scopes.You can see the famous Coal Sack dark dust cloud as a circular "hole" in the Milky Way, with Crux, the Southern Cross, right next to it. Just above and to the right (at the lower tip of the elongated dark patch in the Milky Way) is the bright star Alpha Centauri, with Beta Centauri just below it. The European Southern Observatory has posted a similar video showing a different part of the sky, too. These videos are from last summer, but there’s a timeless, enthralling quality to them.
Credit: ESO/José Francisco Salgado