Tag: VLT

Saturn storm cranks the heat WAY up

By Phil Plait | October 26, 2012 7:00 am

In late 2010, amateur astronomers discovered a white spot on Saturn – a gigantic storm forming in its northern hemisphere. The storm grew rapidly, and within weeks had embiggened to an almost unbelievable size, much larger than our entire planet. The winds in Saturn’s atmosphere sheared the storm, pulling it apart while it still raged, and after three months the storm had wrapped completely around the planet, stretched to the ridiculous length of 300,000 km (180,000 miles) – 3/4 of the distance from the Earth to the Moon!

By mid-2011 the storm had nearly subsided – its remnants could still be seen in images taken by the Cassini spacecraft orbiting the ringed world – but the teeth had been taken out of it. Still, there was one surprise left in it.

Observations taken in the infrared by Cassini as well as from Earth show that the storm was not just big and violent, it also formed a vortex (a storm within a storm, if you like) that got hot – well, hot for frigid Saturn, that is. In the heart of the system, the temperature rose by an incredible 80° Celsius – a difference in temperature that’s like starting in the depths of winter in Anchorage, Alaska and then going to the height of summer in the Sahara!

The image here [click to encronosenate] is from the Very Large Telescope in Chile, and was taken in the infrared, where the heat in the vortex is fairly obvious. Mind you, it’s not like it was a firestorm: the maximum temperature was still a chilly -150° Celsius, but compared to Saturn’s usual -220 or so degrees, that’s pretty dang hot.

The rise in temperature was unexpected. A 20° rise is about the usual fare for these things, but then, this wasn’t a usual storm. Apparently, this hot spot started as two separate vortices, spawned by the storm seen in visible light, and moving around the planet at slightly different speeds. They eventually merged, forming this one ginormous vortex, which at its biggest was over 62,000 km (38,000 miles) across. Interestingly, it grew to this size around the time the visible storm had faded away.

Here’s a video from NASA’s Goddard Space Flight Center featuring planetary scientist Brigette Hesman describing the event:

Like any planet with an active atmosphere, storms on Saturn are common, but one this big had never been seen before. I’d say it was fortunate that we had a spacecraft like Cassini orbiting the planet when the storm erupted, but luck had very little to do with it: it was hard work and dedication that gave us that view. Cassini is such a well-crafted machine that it has operated nearly flawlessly for over eight years orbiting the distant planet. Its design and launch took decades to complete, and it took another seven years just to get to Saturn in the first place.

My point? Luck favors those who are prepared and have planned for rare circumstance. A storm like this one may not happen very often, but we were ready for it by having Cassini there in the first place, and by having a fleet of Earth-based telescopes with their eyes on the sky to support it.

… and having said that, I’ll note an irony: although it was right there, Cassini didn’t discover the storm in the first place. Why not? Because there’s just too damn much to see in the Saturn system! The storm erupted rapidly, and Cassini was busy looking at the rings and moons, so it missed the storm’s genesis. This is not a failure on the part of Cassini or its designers and users: instead, it should be seen as a clarion call for more spacecraft, more explorers in our solar system observing all the myriad worlds.

When I see images and science like this, I am filled with awe and joy, but I’m also struck with an implacable thought: what else are we missing?

Image credit: Leigh N. Fletcher, University of Oxford, UK, and ESO; NASA/JPL-Caltech/SSI

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CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post
MORE ABOUT: Cassini, Saturn, Storm, VLT

An astronomer's paradise

By Phil Plait | February 5, 2012 7:00 am

Cerro Paranal, in the high, dry, Atacama desert in Chile, is where some of the best astronomy in the world is done. It’s graced with incredibly dark and steady skies, and a view of the southern hemisphere skies that, frankly, makes me jealous.

So it’s hard to argue with the title of this short time lapse video, An Astronomer’s Paradise:

This was taken by photographer Babak Tafreshi, who alerted me that he had put it online. Watch it to 1:30 in if only to watch Orion rise — upside down, to my northern hemisphere bias! — with colors and texture that are simply stunning.

Isn’t that awesome? And then a few seconds later, he shows a still image of the great Carina Nebula with the four domes of the Very Large Telescope Interferometer silhouetted against the sky. You can get a better look at that at The World At Night website, which has amazing shots of the sky.

I hope someday to make a trip to this part of the world. To see this for myself…

Credit: Babak Tafreshi

CATEGORIZED UNDER: Astronomy, Pretty pictures

Gallery: Cosmic pictures from the AAS

By Phil Plait | January 17, 2012 7:00 am

Time lapse: Chinese rocket caught on video

By Phil Plait | January 16, 2012 7:00 am

Not that any time lapse video of the Very Large Telescope complex at Paranal in Chile would be normal, but this one by Farid Char caught something pretty unusual: what appears to be a Chinese rocket boosting a satellite to orbit!

Did you catch it? From 14 – 18 seconds in, you can see it as a bright object moving against the setting stars to the west. If you pause the video, you can see what look like two plumes of gas coming from the object (though I wonder; a cone-shaped plume might look like this too seen from the side due to limb-brightening). Given the time, it was most likely the Chinese satellite FengYun 2-F moving into its transfer orbit (or possibly just venting some fuel), and it will slowly boost itself to a final geosynchronous orbit over the next few weeks.

These time lapse videos are always pretty cool, but they’re even better when they get a surprise like this!

Tip o’ the lens cap to eundas on Twitter.

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CATEGORIZED UNDER: Cool stuff, Pretty pictures, Space
MORE ABOUT: FengYun 2-F, time lapse, VLT

Alphas in the heart of the Omega

By Phil Plait | January 5, 2012 7:00 am

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.

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INSANELY cool picture of Comet Lovejoy

By Phil Plait | December 24, 2011 7:00 am

The pictures of Comet Lovejoy keep coming, each cooler than the one before. It’s hard to imagine topping the ones from the Space Station, but then you don’t have to imagine it when you can just look at this crazy amazing shot:

Holy Haleakala! [Click to stimulatedemissionate.]

Well, actually, "Holy Paranal!" This picture, by Gabriel Brammer, was taken at the Very Large Telescope observatory on Cerro Paranal in the Atacama desert in Chile, and it’s just stunning. The comet is obvious enough — you can still see the two tails — and the crescent Moon, somewhat overexposed, on the left. On the right is the VLT itself, firing a laser into the sky. The laser makes atoms high in the atmosphere glow, creating an artificial star that can be used to compensate for turbulence in the air, creating sharper images.

I love how the Milky Way is splitting the sky. You can see the dark hole of the Coal Sack, a thick dust cloud that absorbs the star light from behind it, and the Southern Cross in the middle of the frame. The two bright stars just below that are Alpha and Beta Centauri, the former being the closest star system to our own. The southern hemisphere gets a better view of the galaxy than we northerners do, since the geometry of the Earth’s tilt puts the center of the Milky Way higher up for them. I’m jealous enough just because of that, but to have this incredible comet visible too? Curse you antipodeans!

[UPDATE: The ESO has added a nice time lapse video to the mix, using Brammer’s photos:

Sigh. So lovely.]

If you’re south of the Equator, the comet will be visible in the east before sunrise for a few more days at least. If you can, go take a look. Comets like this are extremely rare, and you may never get another chance like this again.

Image credit: Gabriel Brammer/European Southern Observatory

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Coincidental spirals for your Monday pleasure

By Phil Plait | October 24, 2011 9:59 am

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

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CATEGORIZED UNDER: Astronomy, Pretty pictures

Virgos have beautiful eyes

By Phil Plait | August 29, 2011 6:30 am

No, don’t fret: I’m not betraying everything I know to be true and suddenly supporting astrology! I’m just having a little joke at the expense of NGC 4435 and 4438, two galaxies in the Virgo Cluster known as "The Eyes", and seen in lovely detail by the Very Large Telescope:

[Click for orbus giganticus, and you really should; the details are beautiful.]

Clearly, these guys know each other. NGC 4438 (upper left) is distorted and drawn out, which is a sure bet that it’s undergone a collision with another galaxy in the recent past. Given how close NGC 4435 (lower right) is to it, that seems like the culprit (though M86, not seen in this shot, is also close by and may be to blame). They may have actually passed right through each other as recently as 100 million years ago! Direct hits between galaxies aren’t like car accidents where the vehicles stop dead; galaxies are mostly empty space, and stars are so small compared to the galaxies themselves that a direct impact between two stars is incredibly unlikely.

But the gravitational pulls from the opposing galaxies can affect each other, teasing out long tails of material just like the one streaming from NGC 4438 . The scattering of dust is also another clue. Although stars don’t collide, gas clouds are much larger, some dozens of light years across. Those do in fact slam into each other, causing them to collapse and form stars (though there’s some evidence that’s not always the case). Vigorous star formation can cause lots of dust to be created, and that’s what we’re seeing in NGC 4438. And it’s all weird and distorted too, clinching the case.

You may notice NGC 4435 is a bit featureless. That’s actually common in disk galaxies that live in clusters. As they move through the cluster at high speed, the intergalactic medium — thin gas expelled from the galaxies — can strip away the gas and dust in a galaxy, like opening a car window can blow out stale air inside.

Galaxy collisions are pretty cool, and a rich field for study. And if you’re patient, you’ll get a great view of one: our galaxy is headed for a close encounter with the Andromeda Galaxy. Given that it and the Milky Way are among the biggest and most massive spiral galaxies in the local Universe, it’ll be a spectacular show. Better reserve your seats now, though. You only have a billion or two years to wait!

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CATEGORIZED UNDER: Astronomy, Pretty pictures

Kali ma… Kali ma… Kali ma, shakti deh!

By Phil Plait | August 10, 2011 7:02 am

[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…

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The punctuated spiral

By Phil Plait | June 8, 2011 11:00 am

Cosmic coincidences always make me smile. The sky is pretty big, so finding two totally unrelated objects close together doesn’t happen often. But it does happen, like in this delightful image of the spiral galaxy NGC 3244 and the star TYC 7713 527-1:

This reminds me of another cosmic photobomb involving a star and a galaxy, but in this one the contrast isn’t quite so severe. The two objects seen here are unrelated; TYC 7713 is in our galaxy, while NGC 3244 is something like 100 million light years away. Maddeningly, I can’t find the distance to the star, so I can’t give you an exact ratio (I know it’s reddish, and a magnitude of about 10.2, but that could mean it’s an orange/red dwarf 100 light years away or a red giant 10,000 light years distant). Still, it’s way way closer to us than the galaxy. A millionth the distance? Maybe.

The galaxy is pretty nice; a nearly perfectly face-on spiral. I noticed it’s a bit lopsided, with one arm poking out a bit. Those clumps along the arm are regions of active star formation, and the dust lanes are clear too. Not bad for a galaxy a mere 2 arcminutes across in size — compare that to the Moon, which is 15 times larger in the sky! In real size, it’s not terribly big as galaxies go: about 25,000 light years across, only a quarter of the size of our galaxy.

In the press release linked above, it says this image was taken "with the help of" Václav Klaus, President of the Czech Republic, who was visiting the Very Large Telescope at the time. I wonder what his involvement was — it’s fun to think of the country’s leader using a joystick to swoosh and zoom the ‘scope. Still, it’s very nice indeed to see a major Head of State paying attention to science. Especially when it’s astronomy, and involved such a lovely image.

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CATEGORIZED UNDER: Astronomy, Pretty pictures

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