Category: Cool stuff

Time lapse: Helvetia’s Dream

By Phil Plait | November 6, 2012 2:19 pm

Oh my, another lovely night sky (and landscape!) time lapse video; this time from Alessandro Della Bella, and called Helvetia’s Dream:

[Make sure you set it to hi-def and make it full screen.]

I love the opening shot! Unless it was just digitally zoomed, it must have taken some planning; you have to know just where the Moon is going to rise to catch it that accurately.

A couple of other things to watch for, too:

At about 45 seconds in, a bright meteor leaves a long persistent train, a glowing trail that gets blown away by the thin but rapid winds 100 kilometers above the Earth’s surface. I actually gasped when I saw that!

At 1:30 you see the stars of Orion setting behind the Matterhorn, zoomed in. The big bright pink blob is the famed Orion Nebula, but just above it is the star Alnitak with a bit of nebulosity around it; the bright patch is the Flame nebula, and barely visible is the much fainter but iconic Horsehead Nebula.

I also love how the clouds – more like fog – flow through the valley. The study of how things flow is called hydrodynamics, and physicists use the word "fluid" to describe the stuff that’s flowing. In common vernacular that means liquid ("Have you been drinking enough fluids?") but in science air is a fluid. So is the thin gas in a nebula, since it can carry sound waves and be shaped by supersonic flow.

Whenever a doctor asks me if I’ve been taking my fluids, I always want to respond, "WHAT? And ionize my cardiovascular system?!"

I’ve never had the guts.

Anyway, one more thing: the Moon setting at the end is actually not full! The long exposure times makes it look that way, but when it nears the horizon you can see it’s really a thin crescent, but the dark part of the Moon is being illuminated by Earthshine: light from the Earth itself softly illuminating the nighttime moonscape, which is then reflected back to us.

There’s poetry in the heavens, if you know where to look.

Tip o’ the lens cap to MichaelPeterson on Twitter.

Related Posts:

- The twice reflected Moon light
- A meteor’s lingering tale
- A new old view of an old friend
- Time lapse: Close to the Heavens

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures
MORE ABOUT: time lapse

DC comics pins Krypton to the star map

By Phil Plait | November 5, 2012 9:31 am

The story of Superman is so well known that I hardly need go into detail. But in case you’re some sort of commie, the idea is that he was born on the planet Krypton orbiting a far away red star, and sent to Earth while still a baby by his parents as their home planet exploded around them. Our yellow Sun somehow gives Kal-El superpowers, and he goes on to star in a series of increasingly poorly-made movies*.

I’ve often wondered exactly what kind of star Krypton orbited and where it was. Up until now all we’ve known is that it was red, and red stars come in many flavors, from dinky red dwarfs with a tenth the mass of the Sun up to massive supergiants like Betelgeuse which outweigh the Sun by dozens of times (I’ll note that a deleted scene in "Superman Returns" indicates it’s a red supergiant).

Well, that’s about to change. DC comics is releasing a new book this week – Action Comics Superman #14 – that finally reveals the answer to this stellar question. And they picked a special guest to reveal it: my old friend Neil Tyson.

Actually, Neil did more than just appear in the comic: he was approached by DC to find a good star to fit the story. Red supergiants don’t work; they explode as supernovae when they are too young to have an advanced civilization rise on any orbiting planets. Red giants aren’t a great fit either; they can be old, but none is at the right distance to match the storyline. It would have to be a red dwarf: there are lots of them, they can be very old, and some are close enough to fit the plot.

I won’t keep you in suspense: the star is LHS 2520, a red dwarf in the southern constellation of Corvus (at the center of the picture here). It’s an M3.5 dwarf, meaning it has about a quarter of the Sun’s mass, a third its diameter, roughly half the Sun’s temperature, and a luminosity of a mere 1% of our Sun’s. It’s only 27 light years away – very close on the scale of the galaxy – but such a dim bulb you need a telescope to see it at all (for any astronomers out there, the coordinates are RA: 12h 10m 5.77s, Dec: -15° 4m 17.9 s).

Which brings us back to the Superman story. I was sent an advance copy, and it’s actually a clever tale, with some relatively solid science in it. I won’t spoil it, but apparently Superman comes to visit the Hayden Planetarium in New York City (where Neil is the director) every 382 days, which happens to be the period of Krypton around the star (known as Rao in the comic canon). Although it’s not said explicitly in the story, it sounds like they try to observe Krypton when it’s at the point in its orbit where it appears farthest from its star, reducing the glare and making it easier to spot.

As for the major plot point of the story, I won’t reveal it. But I’ll give you a hint: Superman is about 27 years old. PLEASE don’t leave any guesses in the comments below until a few days after the issue is out. I want to avoid spoiling it for any other readers.

Being a dork, I have to comment on some of the science in the story, though. Given the mass of a star and the period of a planet orbiting it, you can find the distance between the two. Doing the math (I’m a dork, remember?) I find the distance of Krypton to its Sun is about 100 million kilometers, somewhat closer than Earth is to the Sun (150 million kilometers).

But remember, Rao is a dim red dwarf! It’s so cool and faint that even at that closer orbital distance, Krypton would be a chilly world. Even if the planet is black as soot (and thereby absorbing all the heat falling on it from Rao) its temperature is still something like -170° Celsius – about -270° F! [If you're curious, I outline how to calculate this on the Bad Astronomy website.] At that temperature oxygen and nitrogen are still gases – barely – but it’s way below the freezing point of water. And if it’s not black, but instead snowy and white, the temperature will be even lower.

So Krypton maybe isn’t the best place for life to arise… still, there are ways out of this. Maybe either the Kryptonians migrated there (they couldn’t find a warmer planet?) or there’s something else going on. If it’s really volcanic then greenhouse gases could be prevalent, raising the temperature. Possibly the planet’s interior is still warm from heat leftover from its formation… or maybe whatever made it warm enough to be habitable also led to its destruction. Comic book science can be pretty ironic.

[DC comics: call me! I have ideas.]

I also feel obligated to note that in the comic, they made the planet look much larger than the star. That doesn’t work; the two are so far away it doesn’t matter if Krypton was on Rao’s near or far side; it would have to appear smaller than the star. We know Krypton is not a gas giant, so it can’t be much more than a few times Earth’s size. Even compared to a red dwarf that’s pretty small.

Still, it does make for a dramatic series of panels, and I’m always willing to let art trump science if need be. And this really is a pretty nifty story.

The issue comes out on November 7, and I’ll be heading over to my local comic store (Time Warp) to pick up a copy. Next time I see Neil maybe I’ll get him to sign it. It’s not too often I get to do that with someone who knows Superman.

Image credits: DC Comics; Digitized Sky Survey/NASA/Skyview

* I love – LOVE – the 1978 Superman movie, and I still to this day listen to the soundtrack, so you can argue with me over this, but you will be wrong.

This actually happens twice per orbit, when it’s on either side of its star. That means the orbital period is actually twice 382 days, or well over two years… and as you’ll see, that puts it farther from its star, making things worse.

Related Posts:

- My comic book premier
- Apparently, Black Widow knows me. And maybe Nick Fury, does, too.
- Great Tyson’s ghost!
- Neil Tyson and I talk time travel

CATEGORIZED UNDER: Astronomy, Cool stuff, Geekery

Breaking up is easy to do. If you’re a comet.

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

So there’s this comet named 168P/Hergenrother. It’s one of a bazillion such iceballs orbiting the Sun, but this one turns out to be more interesting than most. For one thing, it has a short period, orbiting the Sun once every 6.8 years or so. Its orbit goes out to about that of Jupiter’s, and reaches down into the inner solar system about as far as Mars. It never gets closer than about 80 million kilometers (50 million miles) to us, so it’s usually relatively faint, and you need a big ‘scope to observe it.

It was discovered in 1998, and made a second pass down our way in 2005. This year, 2012, it came by again, and folks around the world observed it as they do any comet. But then, in September, it gave us a surprise. A big one. Lots of observers were reporting that practically overnight the comet grew hugely in brightness, getting as much as 700 times brighter than expected! Not only that, but observations showed the shape of the comet had changed, going from fairly point-like to much fuzzier.

That could mean only one thing. The comet was breaking up.

The picture above is from the Faulkes Telescope North, located on the Hawaiian observatory on Haleakala. It’s a composite of lots of separate exposures that were added together; you can see the stars are trailed (actually stippled; each exposure was short but then shifted to line up on the comet). The comet is the bright fuzzy blob in the upper right, and if you look just below the main part you can see a second fuzzy blob, much fainter.

That’s proof positive the comet calved, or had a big chunk break off. In fact, observations using the huge Gemini telescope show that the main body has broken up into at least four pieces! So what does this mean?

First, don’t panic. We’ve seen this happen to comets before, and this one is so far away from us we’re in no danger at all. It literally cannot get near us.

Second, it’s very interesting scientifically. Comets are basically big frozen snowballs peppered with rock. Imagine scooping up a handful of gravel and snow and then packing into a loose ball. That’s a comet, if your snowball is several kilometers across and the ice is actually frozen water and carbon dioxide. When they are far from the Sun comets stay frozen and are exceedingly dim. When they get closer, the ice goes directly to a gas (called sublimation), and escapes from the solid part (called the nucleus). It expands and can form a big fuzzy head around the solid nucleus that can be tens of thousands of kilometers across, bigger than planets! This is also what gets blown back by the solar wind (and the pressure of sunlight) to form the tail(s) of the comet.

This means that every time a comet gets closer to the Sun and starts to sublimate, it dies a little bit. Material leaves the comet and never comes back. But that ice is what holds the comet together! So sometimes enough ice turns into a gas and escapes that the comet gets substantially weaker, and big chunks of it can dislodge, falling away. That’s what appears to have happened to Hergenrother.

While we’ve seen this before with other comets, it’s not like it happens every day, so any chance to see this occur is fascinating. In 2006 we watched as comet 73P/Schwassmann-Wachmann 3 literally disintegrated. Even more amazing, in 2007 the run-of-the-mill comet 17P/Holmes suddenly erupted, getting hugely brighter, and a huge shell of dust was seen to be expanding around it. Now we think Holmes collided with a small asteroid, and the violence of the event blasted off the material. I saw Holmes with own eyes when this happened, and even though it was past the orbit of Mars, the shell of dust was easily visible to the naked eye. It was awesome.

No two comets are ever really alike. They have different sizes, shapes, compositions, and orbits. And each will behave slightly differently as they round the Sun and head back into deep space. If there’s a lesson from Hergenrother, it’s this: it’s always a good idea to keep an eye on everything in the sky. Just because something looks routine now doesn’t mean it won’t try to pull a fast one later.

Tip o’ the Whipple Shield to AsteroidWatch NickAstronomer. Image credits: Hergenrother: LCOGT/Giovanni Sostero, Nick Howes, Alison Tripp & Ernesto Guido; Holmes: Tamas Ladanyi

Related Posts:

- Ten Things You Don’t Know About Comets
- The Sun ate another comet
- Hubble peers into the weird heart of Comet Holmes
- Rosetta: mission to land on a comet

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

The single greatest vacation picture ever taken

By Phil Plait | November 4, 2012 6:00 am

On Halloween 2012, when people were assembling their costumes and candy, the Mars Curiosity rover was assembling something truly spectacular: a jaw-dropping high-definition self-portrait that has to be seen to be believed:

[Click to enjohnny5enate. And yes, oh my yes, you want to.]

This incredible picture is a mosaic made up of 55 hi-res images taken by the MAHLI, the Mars Hand Lens Imager. That’s a camera designed to be able to take close-up shots of nearby rocks and other feature, but can also focus all the way out to infinity, allowing it to take pictures of distant geographical features as well.

Or, in this case, itself! Now get this: MAHLI is located at the end of the two-meter robotic arm. That was extended and then aimed back at the rover so it could take the pictures (think of every Facebook pic you’ve seen of party revelers holding a camera up and taking a snapshot of themselves). So why don’t you see the arm in these shots? It’s because it was edited out! The camera took several pictures which overlapped. So you’d get two shots of, say, the main body of the rover, each with the arm blocking a different part of the rover’s body. By combining the parts of each picture that don’t show the arm, you can edit it out of the final product. [UPDATE: What I said is technically possible, but not in fact what happened! Emily Lakdawalla has - haha - the scoop on this.]

In the end, you’re left with a pristine (if somewhat distorted) view of the rover as if you were standing there. And there’s so much more than just the rover! The rocks and sand covering the ground, the wheel tread prints in the surface, the small plain the rover sits on. And you can see the layered hills in the distance; those rise up to become the central peak of Gale Crater, Curiosity’s home… and also the rover’s eventual destination. Remember, it’s a rover. It roves.

Pictures like this also let engineers assess the rover’s status. They can look over the different parts and make sure everything’s OK, and also use it as a baseline in case something goes wrong later. It’s far more than just a pretty picture.

But oh my, it’s such a pretty picture!

You can get more info at Universe Today, and Emily Lakdawalla at The Planetary Society Blog points out some fun stuff to look for in the shot, too.

And, I suppose, the title of this post is somewhat misleading. It may look like Curiosity is sitting on a sandy beach somewhere, taking its own "Wish you were here!" picture. But in reality, it’s no vacation. Curiosity is there to work. And it has just two Earth years to unravel a few billion years of Martian history.

Image credit: NASA/JPL-Caltech/Malin Space Science Systems

Related Posts:

- Pew! Pew! Take *that*, Mars!
- Now you will feel the firepower of a fully armed and operational Mars rover
- Wheels on Mars
- One small tread for Curiosity, one giant leap for roverkind
- Curiosity looks Sharp
- Gallery – Curiosity’s triumphant first week on Mars

CATEGORIZED UNDER: Cool stuff, NASA, Pretty pictures

The return of Something Fierce

By Phil Plait | November 3, 2012 7:03 am

Regular readers of my long-standing crush on singer/songwriter/siren Marian Call. Her voice is lovely, her lyrics brain-poking, and her self-motivated music career an inspiration.

So I’m really pleased to let y’all know she is re-releasing her last album, Something Fierce. She’s doing this for several reasons, but one is to get it more widely released. She wants to get on NPR and other places where the audience for her would fit right in.

Of course, this is Marian we’re talking about, so she’s gone to ridiculous lengths to do this. She wants her listeners to participate, to be a part of this. So she’s done something both silly and clever (typically): she’s started a treasure hunt. Well, she’s calling it Adventure Questing because, let’s face it, her fans (of which I am a big one) are all geeks. Anyway, she’s issuing one task per day to her followers, and they’re, well, silly and clever. I won’t give anything away; instead, just go look.

Also, follow her on Twitter for updates and such.

This all started on November 1 – sorry, I know I’m late, but there has been some other stuff on my mind lately – and ends on the 13th. So go and start questing adventurously! And know that what you’re doing is helping support an extremely talented artist who has worked enormously hard to get where she is, and does it all for the love of music, and the love of fans. That’s honest truth, and one of the many reasons I really dig her.

Related Posts:

- Rocketfest!
- Something Fierce
- The (Marian) Call of Mars
- Clarion Marian Call

CATEGORIZED UNDER: Cool stuff, Geekery

Reminder: Donors Choose

By Phil Plait | November 1, 2012 12:45 pm

[UPDATE (Nov. 2): I've just been informed the Challenge has been extended to November 9th due to the chaos on the east coast.]

A quick reminder: I am participating in the Donors Choose Science Blog Challenge to raise money for teachers in need. The funds go to educators in at-risk schools so they can get the tools they need to teach kids math, science, and other topics. I have more background on this in my first announcement post.

If you were thinking of donating, I have some nice news: Donors Choose has set up a matching fund! Every dollar you donate (up to $100 per donation) will be matched by Donors Choose themselves. This is a $50,000 pool of money they have promised, which will buy a whole lot of science for kids who are curious and excited about the world, but lack the resources to fill that desire.

When you fill out the donation page, a text box will come up asking for a code. Just enter SCIENCE, and your donation will double. It’s just that simple. This offer will go through the end of the campaign (on November 5) or when the money runs out, whichever occurs first. As I write this, 18 people have donated a total of $2000 which is going to over 400 students. That warms my heart immensely.

As always, thank you for helping out. If you’ve ever seen a kid’s face when they get that "AHA!" moment in a science class, then you’ll know why I love this funding drive. We’re literally bringing the world to these students, and it means the world to them.

CATEGORIZED UNDER: About this blog, Cool stuff
MORE ABOUT: Donors Choose

Look! Up in the sky! It’s…it’s… it’s an amazing optics display

By Phil Plait | November 1, 2012 7:00 am

It’s funny what tiny little ice crystals can do. Floating high in the air, suspended by air currents, they hang there… and then a ray of sunshine enters them. The light gets bent due to complicated physics, the interplay of that beam of light passing from air to a solid crystal and out again. But once that beam leaves, the sky can light up with a wizard’s pattern of colors and shapes. And if you’re very, very lucky, you’ll see something that you’ll remember the rest of your life.

Something like this:

Holy diffractionation! [Click to heliocanesenate.]

Mind you, this picture is real. David Hathaway – appropriately enough, a solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Alabama – took it using a wide-angle lens to get the whole thing. It’s a High Dynamic Range shot, meaning he combined pictures with 3 different exposure times to see both faint and bright things simultaneously. He took the shot on October 30, 2012.

Everything you’re seeing here is pretty well understood: they all have a name and a specific set of circumstances under which you can see them.

The Sun is the bright blob near the horizon. It’s circled by the 22° halo, a fairly common optical effect in the winter; I see dozens every season. On either side of the Sun are parhelia, nicknamed sundogs. Those are the teardrop-shaped rainbows. Sometimes, as seen here, these stretch out into long streamers called parhelic circles. They are parallel to the horizon but in this wide-angle shot the shape is distorted, bending them up.

Directly above the Sun, dipping down to touch the halo (the math term for this is osculating, which means kissing) is a gull-wing curve called the tangent arc. Above it, connecting the "wings", is the Parry arc.

As an aside, I’ve seen tangent arcs only twice in my entire life. One was at a University of Virginia football game in the winter when the Sun was setting. It was so bright and looked so much like a V that I joked that it was a sign we’d win the game. Georgia Tech trounced us. So much for divination using signs in the sky.

Above the tangent and Parry arcs is a faint rainbow (well, it’s not caused by raindrops, but it’s broken up into colors and has the familiar rainbow-shape) called the Parry supralateral. Faint and off to the right, nicking the supralateral, is a tightly-curved rainbow called the Parry infralateral.

Amazingly, there are still two more to go! The upside-down rainbow at the top is called a circumzenithal arc, because it’s centered on the zenith, the point directly above your head.

Finally, the last thing I can see is a very faint white vertical oval on either side of the the 22° halo and going off the top of the frame, past the circumzenithal arc. That’s the heliac arc, something I’d never even heard of before looking it up here. That’s a new one for me.

Amazing, aren’t they? And get this: there are lots more kinds of phenomena like this, and they’re all caused by ice crystals in the air! The crystals have different shapes – some are flat, some barrel-shaped, so they bend light differently, and their orientation to us causes all these fantastic displays.

By coincidence, just a few days ago BABloggee Joe DePasquale (who works at the Harvard Smithsonian Center for Astrophysics) also saw an aamazing display. Here’s one of the shots he sent me:

Wow. You can see a lot of the same features as in David Hathaway’s picture, too (in fact, Joe made a diagram so you can see what’s what). BABloggee Alan French let me know that there’s a fine gallery of them on Flickr, too.

It’s possible some of this was due to ex-Hurricane Sandy getting moisture high in the atmosphere where it could freeze into crystals. But I’ll note again that I have seen many of these same haloes myself. Most are not rare at all, and all you need to do is keep your eye on the sky. Seriously, one of the first things I do on any day where there are high clouds is look near (not at!) the Sun and see if there’s anything to be seen.

Usually there isn’t. But sometimes, just sometimes, you get that amazing display that makes all the fruitless searching totally worth it.

Look up! There’s a whole Universe out there. And some of the coolest stuff is really close to home, literally just over your head.

Image credits: David Hathaway; Joe dePasquale, used by permission. Tip o’ the Snell’s Law to and to Elwood Herring for pointing it out to me.

Related Posts:

- Halo, how ya doin’ (a picture I shot myself, and one of my very first blog entries!)
- Ring around the Moon
- Moon doggies
- A Sun pillar gooses the sky
- A warm greeting for the frigid Moon

CATEGORIZED UNDER: Cool stuff, Pretty pictures, Top Post

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!

MORE ABOUT: Halloween

Unfurled aurora

By Phil Plait | October 29, 2012 7:00 am

Every time I think I’ve posted just the most sensational aurora picture I’ve seen, another one comes along that has me scraping my jaw off the floor. Check out this shot by photographer David Cartier:

[Seriously, click to enbirkelandate.]

I know, right? That spiral shape is fascinating. Aurorae are formed when charged particles from the Sun slam into the Earth’s magnetic field and interact with it. They’re channeled down into our atmosphere, guided by the Earth’s field, and the shape of the aurora reflects the underlying magnetic field lines. They take on fantastic shapes, including spirals like this, but I don’t think I’ve ever seen curled in a way so well-defined and crisp.

If you look carefully at the bigger version, you’ll see some familiar stars like those forming the constellation Auriga in the center, while the Pleiades are visible nestled in the spot right where the aurora starts to wind up. The bright "star" which is also reflected in the water is actually Jupiter. I had a hard time distinguishing it from the bright star Aldebaran in Taurus, but I think that’s lost in the brightest part of the spiral (though you can see it better in the water to the right of the stretched-out Jupiter reflection).

David lives in the Yukon Territory, not far from the southeast corner of Alaska, and I imagine aurorae are a fact of life there. He has quite a few devastating shots of the northern lights in his Flickr stream. Treat yourself and take a look. His shots of atmospheric phenomena are also incredible.

Related Posts:

- Aurora, in the pink (explaining aurora colors, and this followup)
- The rocket, the laser, and the northern lights (still one of the best aurora pix ever)
- Shimmering purple aurora after a powerful solar storm
- Up, up, and aurora!

CATEGORIZED UNDER: Cool stuff, Pretty pictures

The Dragon returns to the nest

By Phil Plait | October 28, 2012 1:38 pm

As I write this, moments ago, the SpaceX Dragon capsule splashed down in the Pacific Ocean after a two week mission to the International Space Station. Splashdown occurred at 19:22 UTC. Yay!

[UPDATE (20:30 UTC): SpaceX has a picture of the Dragon floating in the Pacific:

Click to ensmaugenate.]

This ends the first operational mission of the Dragon. It’s the first of twelve contracted by NASA to bring supplies up to and back from the ISS. There was no live coverage of the splashdown, unfortunately (and no, I don’t know why; I imagine that’ll come out soon) but NASA did get footage of the Dragin un-berthing from ISS. Here it is, sped up 15x:

I should add the "Enterprise leaving drydock" music from Star Trek II in there.

Anyway, congrats to everyone at SpaceX and NASA. I’ll note that while most of this mission went smoothly, there is still the issue of the engine that failed during launch, resulting in the loss of an ORBCOMM satellite secondary payload. Hopefully SpaceX will discuss this more during the mission wrap-up.

Image credit: SpaceX

Related Posts:

- Frankenstorm and the Dragon
- SpaceX Falcon 9 lost an engine on the way up; Dragon on its way to ISS
- History is made as Dragon splashes down safely in the Pacific!


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