Category: Astronomy

Purple shag Sun

By Phil Plait | November 1, 2012 10:05 am

The great astrophotographer Andre van der Hoeven sent me a shot he took of the Sun a few days ago. Looks like either Barney or the Grape Nehi folks paid it a visit:

[Click to envioletenate.]

Pretty cool. First, of course, the purple color is not real. It’s just the color Andre chose for this picture when he processed it. Second, he used an Hα filter, which lets through a very narrow slice of light (actually in the red part of the spectrum). This color is emitted by warm hydrogen, and is preferentially under the influence of the Sun’s magnetism. You can see arching prominences – huge towers of gas – off the edge of the Sun. The long stringy bits on the face of the Sun are called filaments, and are actually the exact same thing as prominences! Prominences are filaments we see from the side, instead of looking down on them. The terminology is a holdover from when astronomers first started observing the Sun, and we’re kinda stuck with it.

Also, Andre inverted the picture, so what looks black is actually very bright, and what looks bright is very dark. Those bright white blotches? Sunspots. For some reason, our brains can pick out detail better that way, and it also gives an eerie 3D sense to the image. He made a close-up mosaic of his pictures, too, which is actually a bit creepy. It’ll keep the Halloween spirit going for another day, at least!

Image credit: Andre van der Hoeven, used by permission.


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CATEGORIZED UNDER: Astronomy, Pretty pictures

They Came From Outer Space

By Phil Plait | October 31, 2012 6:00 am

Space is scary.

Supernovae explode, flooding their neighborhood with deadly high-energy light and blasting superheated matter outward at a large fraction of the speed of light. Black holes gobble down everything around them, and they’re sloppy eaters, spewing out deadly radiation and belching vast winds of gas. Galaxies collide, asteroids impact, entire worlds are chewed to dust by their violent stars.

And since ’tis the season, here’s a gallery of spooky pictures of nature: moaning nebulae, screaming stars, ghastly volcanoes, and more. Y’know, we humans love to make up stories about vampires and goblins to scare ourselves, knowing they’re just stories… but the Universe is real, and really, really terrifying. Mwuhahahahahaha!

Happy Halloween from the BA Blog!

chandra_tarantula
adamblock_vdb1_scream
bloodyaspeneye
chandra_perseuscluster
eyjafjallajokull_radar_2
ngc2467_2
runningghost_2
sgraw1ly_2
sh2-136blocks_2
skullflower
spitzer_dr6_2
vista_heartandskull_2
witchheadnebula_2

MORE ABOUT: Halloween

Looking up to Saturn

By Phil Plait | October 30, 2012 7:00 am

Just in case you’ve forgotten how brain-destroyingly big Saturn is:

[Click to encronosenate.]

This shot of the ringed wonder was taken by the Cassini spacecraft when it was well over 2 million kilometers from the planet. The spacecraft was south of the rings, looking "up" toward the north. The Sun is shining down on the rings from this perspective, so they look darker than you might expect, and the use of a near-infrared filter accentuates storms in the southern hemisphere cloudtops.

So why does this picture grind my mind to dust? Look at the the very top, near the center. Can you see that dot of light? You might need to click the picture to get the hi-res version to see it better; that’s how small it is.

Except it isn’t. That dot of light is Mimas, a moon of Saturn, and it’s 400 km – 250 miles – across! That’s roughly the size of the state of Missouri, and compared to Saturn it’s reduced to a mere pixel of light. And even then, Saturn’s rings are still too big to fit in this picture!

The scale of the solar system crushes me. And yet there we are, poking around and sticking our noses into it. We humans are pretty awesome.

Image credit: NASA/JPL-Caltech/Space Science Institute


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Time lapse: Close to the Heavens

By Phil Plait | October 29, 2012 12:15 pm

[Personal note: With a hurricane bearing down on the US, I dithered over posting this now… but maybe some of you good folks could use more Moments of Calm.]

Astronomy PhD student Péter Pápics sent me a note about a time lapse video he made at the Observatorio del Roque de los Muchachos on La Palma in the Canary Islands. I’ve been to this observatory, attending a meeting there many years ago. It’s a place of incredible beauty, so I was eager to see his video, and when I watched it I was thrilled to see it was even better than I hoped. Here is Mercator: Close to the Heavens. Make sure you set it to hi-def and full screen.

Many time lapse videos now use a small motor-driven rig to move the camera very slowly as it takes the pictures, but that limits how long a sequence you can shoot. Péter made two choices here: to use a steady tripod which allows longer shots, and to pick a frame rate that accentuates the magnificent grace of the motion depicted. The clouds flow like oceans, and the stars move serenely. His choice of Moonlight Sonata works well here, especially since the sequences are shown in time order, with the setting Sun leading to a night of observations at this important and heavily-used astronomical site.

I’ll have to bookmark this video; when I’m feeling stressed or overwhelmed with the need to save the world, this will help me remember what it is we’re trying to save.


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Namibian quiver trees and the glow of a galaxy

By Phil Plait | October 28, 2012 7:00 am

Florian Breuer is a mathematician who teaches in South Africa. He’s also a photographer, and created this spectacular panorama of the Quiver Tree Forest near Keetmanshoop, Namibia.

[Click to embiggen and see the whole shot; I had to crop it a bit to fit here.]

Isn’t that gorgeous? The arch of the Milky Way behind the trees is beautiful, and when I look at this picture I can’t help but think of an array of radio telescope dishes turned toward the heavens.

By eye, the Milky Way is easily visible on a dark night from a dark site. The diffuse glow of the distant stars is interrupted by the accumulated absorption by clouds of dust between them and us, splitting the glow along its middle. In photographs like this, of course, those features leap right out.

Do you want to take pictures like this? Florian wrote up a pair of essays (first and second) describing how he made this and a few other images from his trip to Namibia. Of course, I suspect the first step is travel to Namibia, which may prove difficult for some of us. Still, there are plenty of places to take devastating pictures of the sky. Maybe even near you! So give it – haha – a shot.

Image credit: Florian Breuer, used by permission


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The return of Sauron’s planet

By Phil Plait | October 27, 2012 7:00 am

First it was there, then it wasn’t, and now it just may be back again: the first exoplanet directly observed orbiting a normal star, Fomalhaut b, has had quite a ride.

[This post has a bit of detail to it, so here’s the tl;dr version: new analysis shows an object orbiting the star Fomalhaut may actually be a planet, enveloped in a cloud of dust. We can’t for sure it exists, but we can’t say it doesn’t, either! Earlier claims of it not existing may have been premature. Also, at the bottom of this post is a gallery of direct images of exoplanets.]

First a brief history. In 2008, astronomers revealed huge news: they had successfully taken images of planets orbiting other stars. Up until then, the only evidence we had of exoplanets was indirect, either by their tugging on their stars which affects the starlight, or by having them pass between their stars and us, dimming the starlight.

But, along with Gemini telescope pictures of a family of planets orbiting HR 8799, Fomalhaut b was the first planet ever seen directly, as a spark of light in a picture. Here is that historic shot:

It’s Sauron’s eye! [Click to embiggen.]

The object is labeled. It doesn’t look like much, but the important thing to note is that it moved between 2004 and 2006 (see picture below), and it was definitely in both images taken two years apart. That means it wasn’t some bit of noise or detector error. Moreover, the movement was consistent with what you’d expect from a planet. Not only that but the star Fomalhaut is surrounded by a vast ring of dust – Sauron’s eye – and the inner edge of the ring is sharp. That’s what you would expect if a planet was orbiting inside the ring; its gravity sweeps up the dust on the inside of the ring. Given the brightness, we were looking at an object with a few times Jupiter’s mass, much smaller than a star, so definitely a planet.

All in all, it looked good, and it looked real.

Then, in early 2012, some astronomers threw a Pluto-esque wet blanket on the news. A planet that big should be bright in the infrared. Fomalhaut is a youngish star, only a few hundred million years old. Any planet more massive than Jupiter should still be hot, radiating away the heat of its formation. They looked for it in the infrared, and it wasn’t there.

Uh oh.

To make things worse, they found that if you extrapolate the orbit of the supposed planet using its movement, it should cross the ring. That’s bad, because its gravity would disrupt the ring after a few million years tops. The ring is there, so that planet means the planet must not be.

Their conclusion: this object is a clump of dust, a cloud, orbiting the star. That fits the data, and a planet doesn’t. Cue the sad trombone.

But wait! We’re not done!
Read More

Awkwardly Embraceable interview

By Phil Plait | October 26, 2012 12:57 pm

My friend, the geekeriffic Jessica Mills, interviewed me for her blog on Tech Republic (the second part is here). It was a lot of fun talking with her; we wandered over topics like Hubble, Star Trek, science, Doctor Who, black holes, Neil Tyson and Bill Nye, and what I would do if I encountered advanced aliens in a wormhole (answer: self-promotion).

Jessica is amazing. She is a writer, producer, and actress, and was the driving force behind the very funny web series Awkward Embraces (which I wrote about in a post a while back). If you’re a geek – and you are – you should watch it.

She’s also just cool and funny and smart and talented, and you could do a lot worse than follow her on Tumblr and Twitter. Hey. She was a Geek-A-Week, so you know she’s cool.

MORE ABOUT: Jessica Mills

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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All These Worlds… 2013

By Phil Plait | October 25, 2012 12:24 pm

My old friend Dan Durda is a phenomenal space artist. His digital pieces are incredible. Last year, he put a dozen of them together to create a 2012 space calendar he called "All these Worlds…".

If you’re looking for an early holiday gift, you’re in luck: he’s done it again this year, making a new "All These Worlds 2013". Here’s the cover:

I know, right? More of his artwork is linked in the Related Posts below, and you can go see his prints for sale, too. So go buy one already!


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A persistent Orionid

By Phil Plait | October 25, 2012 7:00 am

Last weekend the Orionid meteor shower peaked. To be honest, it’s a rather weak shower, with a max of maybe 25 meteors per hour. I mentioned it on Twitter and other social media, but it’s usually a so-so shower at best so it didn’t seem worth it to plug it much. Even big showers like the Perseids, Leonids, and Geminids can be fairly variable in what you see, so I usually only plug the bigger ones.

Still, the Orionids can be nice if you have dark skies. Mike Lewinski went out to Embudo, NM (along the Rio Grande river) to do some meteor photography and happened to catch a spectacular fireball from the shower. It even left what’s called a persistent train, a trail of ionized, vaporized material that can glow for quite some time. I combined three of his images into one composite to show you the sequence:

On the left is the fireball, in the middle is the glowing train (as well as a second meteor that fell along the nearly same path as the first), and on the right the trail some minutes after the original meteor. He said the train was visible for over half an hour! He also put together a time lapse animation of it:

[Note: You may need to refresh this page to see the embedded video.]

It’s pretty fast, so you might want to run it a few times. Mike also created a second video that’s zoomed in.

I guess the lesson here is that it can’t hurt to go out and observe meteor showers (here’s a site where you can see when the next one is). You might catch something pretty amazing! And even if you don’t, it’s still a night out under the stars, and that’s still one of the best ways you can spend your time.

Image credit: Mike Lewinski, used by permission


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CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures
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