Bad Astronomy
The entire universe in blog form

June 8 2016 8:45 AM

The White Spots on Ceres Aren’t the Only Weird Thing There

When I was kid, we didn’t know nearly as much about asteroids as we do now. This was before we had spacecraft visiting them, really high-res radar observations, and all the other amazing tech we have now. I’m not saying we knew nothing—quite a bit was understood—but things have changed a lot since then.

For example, for two centuries we thought of Ceres as the largest asteroid, but now planetary scientists are starting to think of it as a protoplanet, an object that was well on its way to becoming a full-fledged planet before it stopped growing. That makes it easier to think of it as a world, with diverse landscape and layered history.

And also a lot of really weird stuff.

You’ve probably seen pictures of the crater Occator, the large 90-km-wide crater with the bright spots in the center that are likely to be salt deposits. Ceres has a mantle of water ice under its surface, probably briny, and it sometimes forces its way up and out onto the surface, leaving behind the bright deposits.

But a new image from the Dawn spacecraft shows that the crater center isn’t the only spot to which we should be paying attention.

rim wall close up
Zoomed in version of the image above, showing the odd features.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The image above shows a section of the northern rim of Occator. At first, I wasn’t too surprised by what I saw. A sharp edge, piles of debris at the rim wall’s base indicating landslides over the eons, and so on.

Then I saw the fingerlike features high up along the rim wall. Were those … gullies? Well, that would be cool! Maybe we’re seeing water ice sublimating, I thought, turning into gas and dislodging debris that would then roll down the wall. We see things like that on Mars, so this would be a big scientific discovery!

But then I looked again. And again … and that’s when I noticed something very odd.

Look at the crater above the rim, to the right of center. See the shadow? The shadow is on the right, which means the Sun is shining from the right. If you look around the image you’ll see plenty of confirmation of that.

Now look again at the “gullies.” See it? The shadow of these features is on the left. That means they aren’t features dug into the surface, they’re actually popping out from the surface like hills!

What. The. What.

I thought I was losing it, so I contacted my friend, fellow science communicator, and Ceres enthusiast Emily Lakdawalla, who confirmed what I was seeing. These are things sticking up like hills, not dug down like gullies.

What a relief!* I wasn’t seeing things. But this brought up another problem: What are they?

Occator
For context, this wider shot shows the rough outline (white box) for the rim wall image above. This image was taken at a different time and spacecraft orientation, so the box is not exact.

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

My first thought was that there must be deposits of tougher material under the surface, but I wasn’t sure how that might work for these features. Emily gave me some ideas, and now I wonder …

Over time, the softer material making up the rim wall slides down, leaving the stronger stuff sticking out a bit. I’ve seen this sort of thing myself in the field; for example a limestone deposit over softer clay. As the clay crumbles and slides down the slope, the limestone sticks out making a ledge. If the tough layer has softer stuff above it as well, that material will flow down around the outcropping. In the very low gravity of Ceres (only 2 percent of Earth’s!) the material could pile up above the obstacle, creating a vertical ridge. Some of the material could continue around it to flow downward, then hit a second outcropping and so on, forming the tributarylike fingers.

Note the wide streaks that continue down the rim wall past the outcroppings, too, indication that flow continued. Although, weirdly (a word I use a lot when writing about Ceres) you can see the large piles of debris at the bottom of the rim under the left group of outcroppings, but on the right there’s just a small rounded lip running along the bottom. I’m not sure why that would be. Perhaps some later event removed them.

Mind you: I’m totally guessing here. I completely absolve Emily if I’m wrong, and give her complete credit if this is right! That’s only fair.

But the overarching point here is that Ceres, like any body on the solar system, has similarities to Earth (mass wasting, landslides, and so on) but is also very different (lower gravity, no air, much colder, etc.). Intuition can’t necessarily be trusted, but it’s not a bad place to start.

Every answer to a scientific puzzle starts off with a simple phrase: “What if…?” Where you go from there depends on the evidence, what we already know to be true, and imagination. But those two words are a great place to jump off.

Tip o’ the talus to NASA’s Dawn Mission.

* HAHAHAHAHAHA! Get it?

June 7 2016 9:15 AM

How Did Supermassive Black Holes Get So, Well, Supermassive?

Supermassive black holes are a bit of a problem.

Well, some of them power the most luminous objects in the Universe, spewing out high-energy radiation and matter at close to the speed of light, probably sterilizing all of space for thousands of light-years around them. So if you’re too close, yeah, they’re more than a bit of a problem.

But besides that, though, they’re a puzzle. Specifically, where do they come from?

Do they grow from normal, stellar-mass black holes that feed off matter gluttonously, or do they grow directly from collapsing gas as galaxies form? This is a huge question in astrophysics right now, and no one knows the answer. But we’re getting closer, and a new, clever bit of research may be a signpost to how these monsters are born.

OK, first, what am I talking about? Supermassive black holes are huge, with millions or billions of times the mass of the Sun. We think every big galaxy has one in its very center, and we know each forms along with its host galaxy itself; both have properties tied to each other. There’s no doubt they’re related.

That means that the supermassive black holes we see in big galaxies today formed along with their host billions of years ago. But how? Galaxies form as huge clouds of gas in the early Universe collapsed under gravity, forming stars. Some of these stars were very massive, which means they lived short, furious lives and exploded. Their cores collapsed to form black holes, some probably with 100 or more times the mass of the Sun.

It’s possible a black hole like that started off in the center of every galaxy, then fed on gas falling into the galactic center to grow huge. Or, it’s also possible that the gas that formed the galaxy itself poured into the center and formed a black hole directly, probably starting with a mass of 100,000 times the Sun or more.

Which is it?

black hole accretion disk
Illustration of a black hole with matter swirling around it, focusing its energy into beams that can travel across the Universe and be detected by us on (or slightly above) Earth.

NASA/JPL-Caltech

Well, forming the smaller black holes first and having them grow in size has a big problem. It takes too long. As material falls in it tends to form a disk around the black hole, which heats up tremendously and glows fiercely (which is why black holes can be so bright—or, more technically, provide the power for intense luminosity—as I said above). That huge amount of energy will slow the incoming material, making it harder for the black hole to grow. Even assuming the best conditions, it means we shouldn’t see million or billion solar-mass black holes when the Universe was less than a billion or so years old.

But we do. And that’s a problem.

However, a group of Italian astronomers may have a way around it. If the material infalling to form the galaxy does directly form a black hole (that is, not forming a star first), it could start off with a mass of about 100,000 times that of the Sun. That could grow to supermassive proportions in the time allotted. But to confirm that, we’d need to find them, and to do that we need to know what they’d look like back then.

It turns out that’s hard to figure out, with lots of different things affecting a nascent black hole’s appearance to us. To tackle this, the astronomers used a theoretical model to determine how such a black hole would emit light as it grew. It turns out the best way to see these objects is through the light they emit in the infrared and X-ray parts of the spectrum.

Looking first at just the infrared light predicted, they then applied this to observations of the deep Universe using Hubble and Spitzer Space Telescope (which observe in the infrared) to look for distant candidates that emitted light matching what they predicted. The idea here is that the farther away the object is, the earlier in the history of the Universe we see it, and using these space telescopes allows us to see all the way back to when galaxies were first forming.

They started with the 35,000 objects found in a deep Hubble survey called CANDELS (for Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey), a very deep survey that saw a lot of distant galaxies. They then narrowed the list down to about 2,000 objects located at the right distance from us to be seen when the black holes were first growing.

The next step was to look for these objects emitting X-rays. That meant using the Chandra X-Ray Observatory, which was also used to observe the CANDELS fields. Out of the thousands of candidate galaxies, just two were also seen to emit X-rays in the right manner.

But two is enough! Well, enough to show that their idea may not be wrong; having two objects doesn’t prove they’re right. But it’s very intriguing that they found any at all. It shows that it’s possible supermassive black holes get their start as directly collapsing clouds of gas, with no star needed to get things rolling.

And the beauty of their method is that they can adapt it pretty easily to use with data from the upcoming James Webb Space Telescope, which is due to launch in 2018. Once that’s up, lots more targets can be identified because it’s a far more sensitive telescope than Hubble or Spitzer in the infrared.

That’s exciting. We know these black holes are critical to the growth and evolution of big galaxies, galaxies like the Milky Way, the one we live in. Not knowing how they got there is a bit irritating. This method may not pan out, but it looks to me like a pretty good start on a way to figure out what’s what. And just having a plan, in this case, is very hopeful.

June 6 2016 12:03 PM

When It Comes to NASA, Polarized Politics Need Not Apply

A few days ago I got into an interesting conversation on Twitter.

As I posted Monday morning, NASA released a pretty amazing image, a mosaic of Pluto taken by the New Horizons spacecraft when it flew past the tiny world back in July 2015. Although the images were taken at the moment of closest approach, it’s taken a long time to download them; New Horizons is more than 5 billion kilometers away, and it’s not exactly connected by a fiber optic line to Earth. The bitrate is very slow, and we had to wait months to get all the high-res images back from the solar system’s suburbs, not to mention the time and expertise it takes to process and put the images together.

Now, I know that (and now you do too!), but not everyone does. We live in an age where we come to expect instant downloads, instant gratification. If you’re not familiar with the process, it can be surprising how long it takes.

So I wasn’t too surprised when I saw a tweet by Fox News Channel host Greta Van Susteren wondering why it took so long to get these images:

There are a few things to parse here. One is that she didn’t know the process of getting the images back from New Horizons, which is understandable. OK, that’s fine. In general, I greatly prefer it when people look such things up (or ask an expert) instead of mulling aloud on social media, especially someone known for being a journalist. But I understand such moments of frustration, and I like to lean toward the principle of charity when I can.

Still, there’s an implied conspiratorial thinking there (or at least others and I inferred it), and the second line about taxes struck me as strongly implying a denigration of the competence of the people involved in the New Horizons mission. I generally stay out of Twitter spats—140 characters rarely allows for any subtlety—but I decided to step in:

So yeah, testier than I might usually reply, I admit. But then this happened:

Huh! I wasn’t expecting a reply (it’s pretty rare), but I took that as a really good sign. She also was clearly curious about what was going on. So I replied with two tweets, to clear things up:

I felt better about this right away. She then replied:

I’ve written about this many, many times, and I know what a mess NASA funding is. So:

And again, I could see her curiosity and frustration with where we are today, especially with her reply:

I was happy with this conversation—many don’t go nearly as well—but still … the replies from other people on Twitter, interjecting in the thread, were not surprisingly all over the place. Given that Van Susteren works for Fox, it was no shock to me that many of the replies from onlookers were of the “Obama ruined NASA” flavor. That, to be very clear, is baloney. I replied to a few people, linking to an article I’ve written about this very topic.

To wit, President Obama has done a lot of good stuff for NASA, as well as made some decisions I consider very short-sighted when it comes to planetary science, but the GOP-held Congress has done far worse by greatly reducing funding for Earth science (due to NASA’s investigation of climate change, which they deny is real) and strangling the commercial space budget that, for example, helps fund SpaceX and other space startup endeavors. They do this in favor of funding the Space Launch System, which I am starting to think of as a massive boondoggle.

Other Twitter repliers were climate change deniers who tossed about their usual baloney. Also jumping in were people who think NASA is a waste of money. These people are wrong.

Of course people being wrong on Twitter is like the air we breathe; always there and sometimes polluted. It’s worse when political motivation stifles rational thinking, honest inquiry, and a willingness to look at facts.

And mind you, I’m sure there’s a very long list of things on which Van Susteren and I disagree. But look what happened! Yes, that conversation started off rocky, but we both took a step back and a deep breath, then actually conversed even if only briefly on a topic we both felt strongly about, and, it turns out at least in general, one on which we agree.

Early on in the back-and-forth, I saw a lot of people jumping on her, calling her “stupid,” accusing her of spinning her first comment, and so on. Besides in this case being unfair, what I have found is that such name-calling is worse than useless if you want to have a conversation; it tends to shut things down. If you’re trying to make a point, and not a dialogue, that’s different. Sometimes you have to call things as you see ‘em.

But when it comes to changing minds one-on-one, whaddya know. Being nicer really does help.

Over the next few months the American election is no doubt going to bring out the worst of many. My opinions are public, and strong. And while I will not waver or back down when it comes to calling out nonsense, neither will I cross the line into dickery.

Do not confuse volume and vitriol with strength, nor restraint with weakness. We have a long, long way to go in this country when it comes to ensuring a more rational debate on any polarized topic, and actual communication will be a critical part of achieving it.

June 6 2016 9:00 AM

A Strip of Pluto

I know, that image above doesn’t look like much, does it? But go ahead, click it. I dare you. Because I took the original 1,000 x 15,000 pixel image, rotated it, and shrank it to fit the width of the blog.

It’s a jaw-dropping close-up look at a very, very long strip of Pluto’s surface, created using the highest-resolution images from the New Horizons spacecraft as it shot by the tiny frigid world in July 2015 at a dozen times faster than a rifle bullet.

Simply scrolling down that image is like mainlining science directly into your brain. NASA kindly released a short video annotating some of the gross features:

We’ve seen most of the subimages making up this composite before, but context is everything when you’re surveying the surface of an alien world.

For example, one of the most interesting features on Pluto (and there are so many to choose from!) is the nitrogen plains making up the western half of Pluto’s heart, called Sputnik Planum (the entire heart feature is called Tombaugh Regio, after Clyde Tombaugh, the astronomer who discovered Pluto). Much of Sputnik Planum is segmented, which is something you see on Earth in frozen lakes, when warm water rises and colder water sinks (called convection) and the frozen surface forms abutting geometric plates.

On Pluto those plates are a few kilometers thick, but underneath them may be more fluid material with the consistency of toothpaste. It convects, possibly at speeds of several centimeters per year. But this raises the question: Why is Pluto’s interior warm? It’s small enough that it should have frozen solid billions of years ago! This is one of the biggest questions the New Horizons observations have generated. Maybe Pluto suffered a huge collision in the past billion years, creating the moons, and warming its interior. Maybe it’s something else entirely. But the nitrogen plains are pointing toward some huge energy input that made Pluto’s interior warm.

Pluto's pits
Sublimation pits dots the frozen nitrogen plains of Pluto.

NASA/JHUAPL/SwRI

Also in those plains are thousands of little pits, probably sublimation features, caused when small pits in the ice grew when warmed by the Sun, the nitrogen turning directly from solid to gas in the near-vacuum conditions. I’ve been intrigued by them since we first saw them in the initial images. Why do so many of them seem to align along lines and curves?

The obvious answer is, again, the surface is moving, pushed around by forces inside the little world. As the ice flows, the pits get stretched out … or perhaps it’s the other way around: The flowing ice gets cracks or deformations in it that then form the pits, already seeded along the stretch marks.

What a weird place.

Pluto's highlands
Sunken mountains? Is anything too weird for Pluto?

NASA/JHUAPL/SwRI

One other thing: Looking along the image strip are these features, labeled as “rugged, dark highlands.” I was struck by how the big one at the upper right appears to have a huge mountain in the middle of it. I wonder if the mountain got pushed up by some tectoniclike force, then subsided (sank), pulling down the surrounding region with it. Or perhaps it's just what's left of the surface as a series of areas collapsed. The giant pit to the lower left doesn’t have such a feature, so clearly there’s more going on here. 

These images are truly incredible, and we’ve had to wait a long time to see them; data are still coming back from the probe, and it takes time to create a mosaic like this. But as hard as it is to wait for the images, it’s even more maddening to have to wait for the papers to trickle in. I want to know what’s going on there, what expert planetary scientists think about them! I’m just thinking out loud here, trying to figure out what I’m seeing, but they have vast experience interpreting such landforms … and yet even they are baffled by what they see in the New Horizons imagery. Such an active and diverse and just plain odd little thing Pluto is!

And it’s just one of dozens of such large bodies out there, in the black past Neptune. Pluto is only the first one we’ve seen up close. I wonder what other bizarreness awaits us when, eventually, we send our probes out there? I hope we get the chance to find out.

June 5 2016 9:00 AM

What Causes Stripey Clouds?

Sixty Symbols is a great effort: A group of professional scientists of various stripes putting out short videos, each one tackling a different symbol in science. ∆F, -K, kg… each one is explained clearly and simply by actual scientists.

The videos proved so popular (more than 53 million views as I write this!) that they kept going. They’re all good, but one popped up recently that I like in particular. Not because of the symbol — capital N is not really all that sensational by itself — but for what it’s used for: the Brunt–Väisälä frequency.

What’s that, you ask? I’m glad you did. It has to do with clouds, and you know how much I love clouds. I’m sure you’re also wondering how that’s pronounced. I’ll let the video explain:

I live very close to the base of the foothills of the Rocky Mountains, and we get these stripey parallel clouds sometimes. The mountain range runs roughly north/south, and the clouds do too.

Sometimes, though, the clouds run perpendicular to the mountains, the parallel lines stretching to the east, and that’s due to a similar process involving gravity waves (not to be confused with gravitational waves), but when the wind is blowing from the north or south. As one layer of air is blown over another layer, it bobs up and down. Gravity pulls it down, it becomes buoyant, then it rises back up, creating ripples.

gravity wave clouds
I took this shot in Boulder county in January 2016. I was facing south; the lines in each ripple run east/west.

Phil Plait

We also get Kelvin-Helmholtz waves, and those are the best. They’re very rare, but I’ve seen them at least twice over the past few months. It happens when a layer of air blows over another layer. At the interface there’s a shear force; it’s like the two are rubbing together. This can lift up a bit of the lower layer, which then gets pushed faster by the layer above it, causing the “breaking wave” appearance.

Kelvin Helmholtz waves
I took this as well in February 2016. The wind above the cloud was blowing southward. You can see the "breaking wave" appearance (inset) to the clouds.

Phil Plait

Isn’t that cool? Finally, and related, we also get orographic clouds, which form when moist air runs into a mountain, lifts up, and forms clouds. We get steady winds over the Rockies for days, and these winds form orographic clouds.

The result is bizarre: A demarcation line just above the mountains, with clear air to the west and clouds to the east; a long, long nearly straight line running along the mountains, north/south. That line will wiggle a bit but stay remarkably steady for days. You expect clouds to move, so that line looks like it should blow east, but it never does. The clouds themselves do, but the line where the clouds start to form holds true. It’s really disconcerting.

You probably see clouds all the time. But do you really see them? It’s worth taking  another, deeper look. 

June 4 2016 8:45 AM

Fireball: Couch-Sized Rock Lights Up the Sky Over Arizona

Last Thursday, June 2, 2016, at 10:56:32 UTC (03:56 local time), a rock the size of a typical living room recliner burned up over Arizona, bright enough to light up the sky and spark a lot of social media chatter and 911 calls.

There are quite a few videos of it online. Here’s a typical one:

The bolide (the technical term for a bright meteor) was probably several times brighter than the full Moon, and as you can see in the video it brightened rapidly, flashed several times (this happens as the solid part breaks apart, releasing energy much more rapidly), then disappeared. It also left a long, thick “smoke trail”, actually vaporized rock that can glow for quite some time. It lasted long enough to get lit up by the rising Sun, and get whipped around by upper level winds, creating an eerie, twisted train:

[In that video you can see the old crescent Moon, too.]

There were enough witnesses and good data from the event that scientists were able to backtrack its path into space, and even get an orbit for it! It was on an elliptical path, tilted to the plane of the planets, going out past Mars, and just to Earth’s orbit.

NASA created a very cool animation showing its path, and an asteroid-eye-view of what it would’ve looked like to be sitting on it as it approached our planet. Watch this!

This looks to be a pretty typical event, one that happens fairly often, maybe once per month or so somewhere over the planet (most go unseen; the Earth is mostly water, and even much of the land surface is only sparsely inhabited). What made this one different to me is that JPL put it up on their fireball page, listing the location, time, and most importantly energy released. They get this info from the government, though exactly who is not clear. As I wrote about it recently:

…as you might imagine, various arms of the military are curious indeed about atmospheric explosions. However, not much information is revealed by the source; just the time, direction, explosive yield, and things like that. I can think of three ways to detect a big fireball in this case: Satellite observations, which would image them directly; seismic monitors, which can detect the explosion as the sound wave from the blast moves through the ground; and atmospheric microphones, which can detect the long-wavelength infrasound from an event.

The explosive yield —the energy released by the event—is what interests me. From that we can determine roughly how big the meteoroid, the solid bit that burned up, might have been. On Twitter I said that the rock was probably a couple of meters across, and I got some questions how I got that number. Let me show you!

fireball stats
The bolide stats posted on the JPL fireball page.

NASA/JPL-Caltech

In this case, the explosive yield was 0.5 kt, or the equivalent of half a kiloton of TNT going off. This energy comes from the motion of the object; it’s moving fast, at interplanetary speeds, and when it burns up in our atmosphere it releases all that energy as light and heat. The velocity of this particular object was not reported to JPL, unfortunately, but a typical value is about 20 kilometers per second.

That energy of motion of an object, called its kinetic energy, is equal to

energy = 1/2 x mass x velocity2

Therefore, the mass of the object is

mass = 2 x energy / velocity2

A number I happen to know is that a megaton (a million tons) of TNT exploding is equivalent to 4 x 1015 Joules (a Joule is a unit of energy). The energy of the Arizona fireball was equivalent to 500 tons, or 2 x 1012 Joules.

Plugging and chugging (and making sure I do everything in the right units):

mass = 2 x 2 x 1012 Joules / (20,000 meters/sec)2 = 10,000 kilograms or 10 tons.

So the object had a mass of 10 tons or so. How big is that? Let’s assume it was a sphere, and made of rock. Rock has a density of very roughly three tons per cubic meter. Knowing that the volume of a sphere is 4/3 x pi x radius3, and density = mass/volume, we can solve for the radius. I’ll save you the algebra and just write down the result:

radius = cube root(3/4 x mass x 1/density x 1/pi)

Plug and chug, and you get the radius is very close to one. So if the fireball was made of rock, it was about two meters across. Sofa sized! NASA reported roughly the same size for it as well. The biggest assumption was the velocity, but it turns out 20 km/sec was pretty close.

Note that the JPL report lists the total radiated energy as much smaller than the yield, only about 10 percent of the total. That’s because not all the energy of the impact goes into light; in general a few percent is about right. The rest goes into heat, sound, and so on.

I’ll note that this chunk of asteroid probably burned up dozens of kilometers over the ground; ones this small don’t hit the ground unless they’re made of iron (in which case this would’ve been smaller than two meters across because iron is much denser than rock). I know some folks are on the lookout for any pieces that might have made it down. I hope someone finds some; it’s rare to get meteorites from an observed fall. There’s a lot of ground to cover! But such meteorites tend to be far more valuable.

I’m glad to see this get so much coverage, too. The more observers who report fireballs to the American Meteor Society, and who get video or pictures, the better we can understand the paths and therefore the orbits of these objects. It also helps us see how they behave as they slam into our air at hypersonic velocities. The physics of that is still not well understood, so the more data we have, the better!

Tip o’ the Whipple Shield to Ron Baalke.

June 3 2016 9:30 AM

Breathe Deep Pluto's Gathering Gloom

At this point, the New Horizons probe is nearly 400 million kilometers past Pluto, more than twice the distance from the Earth to the Sun, now almost a year after it shot past the diminutive ice world.

But on July 15, 2015, just after it passed Pluto, it turned around and took a series of high-resolution images looking back toward Pluto. Those images have been processed and put together into a stunning mosaic, shown above. Well, a small version of it; click it to get the magnificent 5,000 x 7,300 pixel version (hint: If you use a image viewer with some control, set the contrast up high to see more features).

This shot is simply stunning. The geometry alone is amazing to me. Pluto is roughly five billion km from the Sun, and from that distance the Earth and Sun are so close together they might as well be sitting in the same spot. So when the probe swept past Pluto, it was heading very nearly straight away from the Sun, and when it looked back to take the images comprising this shot, the Sun was on the other side of Pluto… when means New Horizons was seeing the dark, unlit side of Pluto.

Well, nearly. Pluto is seen as a thin crescent, a bit of its surface visible. But its atmosphere! What little gas Pluto has over its surface is incredibly thin; the Earth’s air at sea level is 100,000 times thicker. But it’s there, and has a series of haze layers in it, probably organic (carbon-based) molecules created as ultraviolet light from the Sun breaks down methane and allows the constituent atoms to recombine. Those layers are easily seen in this image.

a cloud on Pluto?
We'll find a cloud to hide us, we'll keep the moon beside us.

NASA/JHUAPL/SwRI

But I’m amazed at the surface detail. This image is not the same as one released in October 2015; the angle looking back on Pluto is different, so different features are visible. Two things in particular are worth noting.

Near the bottom right of the image, just inside the limb of Pluto, there’s a very odd whitish feature. It looks fuzzy, doesn’t it? That might be —might be— a cloud. Sunlight can warm the surface of Pluto enough that a low-lying methane cloud could exist. It would be hard to see looking straight down on it, but because we see it here at such a low angle (and with the Sun shining nearly through it) it appears more obvious. It may just be a surface feature though. It’s very hard to tell. We may never know: New Horizons was a flyby mission; there was no way to carry enough fuel to go into orbit. Because of that it flew past and that’s that.

mountains on Pluto
In and around the lake, mountains come out of the sky, and they stand there.

NASA/JHUAPL/SwRI

Higher up around Pluto’s limb are a series of mountainous features. These are darker, possibly made of water ice covered with more of those complex organic molecules. You can see them poking right over the horizon, and there’s one about a third of the way down from the top whose base is clearly over the horizon, with the peak sticking up high enough to see. Incredible.

From a distance, Pluto looks pretty round, but it’s obvious from this view that it’s actually quite bumpy. Mountains of water ice as high as three kilometers climb out of it. Pluto is much smaller than Earth (2,370 km versus nearly 13,000), so to scale mountains that big on Earth would be over 16 km high, almost twice as high as Mt. Everest. Earth is a lot smoother than Pluto.

As I was looking at this image, I found myself applying scientific diagnostics to it. My eye went to each little feature, ever change in contrast and size, my brain ticking over trying to categorize, analyze, understand.

But then I zoomed out, and saw the whole image filling my screen, and unbidden a thought leapt to me:

In this picture we’re seeing all the sunrises and all the sunsets all at the same time all over Pluto.

This little world, so distant and cold, may be of enduring interest to scientists for centuries to come. But it also is poetry. Art.

Let it incite and excite all the parts of our brains, as all natural wonders should.

June 2 2016 12:08 PM

Scientists Stand Up To Congressional Attacks

To the surprise of no one, Lamar Smith (R-Texas) is continuing his unfounded attack on science, ratcheting it up even higher than before. This time, he’s trying to tie up the Union of Concerned Scientists (UCS). The good news? They’re having none of it.

OK, let’s get you caught up first. Smith is the head of the House Committee on Science, Space, and Technology, and is also a 100 percent head-in-the-sand climate change denier, as well as a conspiracy theorist. A list of his nonsensical claims would take a long time to catalog, so here are just a couple: He thinks that scientists are manipulating data to make it look like the Earth is warming, and that the global warming pause is actually a thing, despite huge, overwhelming amounts of evidence that it isn’t.

Sadly, as head of the science committee he has the power to manifest his conspiracy ideations. He has used the threat of “Congressional oversight” to harass scientists at the National Oceanic and Atmospheric Administration, including subpoenaing its administrator, Kathryn Sullivan, a scientist and ex-NASA astronaut. The minority (Democratic) committee ranking member, Eddie Bernice Johnson, protested this move vocally. The NOAA refused Smith’s ridiculous request. Smith then slipped into some sort of alternate reality, demanding information from the NOAA because he thinks he has whistleblowers who claim NOAA scientists rushed a global warming paper into publication. Johnson wrote yet another letter to Smith protesting his actions. Smith responded by overreaching even more, broadening his McCarthy-esque fishing expedition against the NOAA.

And that brings us to now.

Earth melting

Shutterstock / Barnaby Chambers

Smith’s been ramping up a new(ish) tactic, trying to flush out what he thinks is a cabal of scientists fighting the fossil fuel industry. On May 18, 2016, he sent a letter to the UCS, an obvious attempt to create a chilling effect on their work to help scientists maintain the freedom they need to do their research. Reading the letter, I don’t think George Orwell could have done any better. He’s claiming that the UCS is trying to “deprive companies, non profit organizations, and scientists of their First Amendment rights and ability to fund and conduct scientific research free from intimidation and threats of prosecution.”

That loud noise you may have just heard was my irony gland exploding.

Smith, who has done nothing but intimidate and threaten scientists with prosecution, has the temerity to accuse the UCS of this. Amazing.

In the letter, Smith says the UCS is conspiring with a score of state attorneys general to work “… against those who have questioned the causes, magnitudes, or best ways to address climate change.”

Yeah, in that last part he means climate change deniers. “Best ways to address climate change.” Please.

Smith has gone back to his tactic of demanding all correspondence, wanting everything —“all documents and correspondence”— from the UCS to the offices of the attorneys general, hoping that a broad fishing expedition will turn up something that, one assumes given repeated past history, can be taken out of context to support his denial.

The UCS has responded, and was very clear about their answer: No.

In their letter to Smith, they are adamant that Smith has vastly overreached his legal authority and jurisdiction. It makes my heart sing to see that they too point out the irony of Smith claiming the UCS is trying to suppress the First Amendment rights of fossil fuel companies while he’s attempting to squelch the UCS’s First Amendment rights.

“Chairman Smith’s letter makes no claim that UCS has violated any law or regulation. Instead, Chairman Smith seeks governmental “oversight” over UCS’s exercise of our core First Amendment right to petition the government to take action on the urgent threat of climate change,” said Ken Kimmell, the president of UCS. “Not only is our activity well within our rights, but Chairman Smith’s request oversteps his committee’s jurisdiction.”
“The law is clear—this inquiry goes well beyond the power granted to Congressional committees,” Kimmell said. “This kind of open-ended investigation is an abuse of power, and we are standing up to it to avoid setting a precedent that could have a chilling effect on scientists, or anyone else, exercising their right to speak out about any vital issue.”

As I have said many times, this is an abuse of power on Smith’s part, pure and simple. He will do anything to slow or stop research into climate change and cast aspersions on scientists, no matter how untrue his claims are.

The final irony? We now know for a fact that Exxon has been misleading the public for decades; they knew in the 1970s that their product could harm the Earth’s environment. Maybe someone should clue Smith in on this, if he can hear it over the sound of fossil fuel industry donations pouring into his coffers.

Sadly, Smith is in a Texas district unlikely to elect someone to replace him (though democrat Tom Wakely is running against Smith in Texas District 21 for the November election, and is very clearly on the side of reality when it comes to climate change). The only way I can see Smith releasing his power is if he has to, and that means the Democratic party gaining a majority in the House this November. That seems unlikely to me as well, though not out of the question.

With record temperatures the past seven months; with 2016 almost certainly going to be the hottest year globally on record (beating out 2015 and 2014); with the Great Barrier Reef sustaining massive (perhaps irreversible) damage due to global warming induced coral bleaching; and with Donald Trump bloviating about droughts and picking a global warming denier as his energy advisor, the sooner the deniers like Smith are out of power, the better our planet—the better all of us, every human on Earth—will be.

Hat tip to climatologist Michael Mann.

June 2 2016 8:45 AM

King Tut Had a Dagger That Fell From Space

Born in Arizona, moved to Babylonia,

He was born in Arizona, lived in a condo made of stone-a had a dagger made of meteoritic iron, nickel, and cobalt-a,
King Tut

—   Steve Martin, “King Tut”

I never in my life would have thought I’d pose this question, but guess what King Tut and I have in common?

I was born in Virginia, not Arizona, so it’s not that. It’s this: We both have daggers made of iron meteorites.

I bought mine (which, technically, is actually a letter opener) at a science meeting a few years ago, and it was the first meteorite-based item I ever got; I now collect meteorites and love them. It’s unclear where Tutankhamen got his (assuming it wasn't the goa’uld), but a paper published recently in the journal Meteoritics and Planetary Science shows pretty conclusively it’s wrought from meteoritic material. That’s interesting historically —for one thing, it supports many studies showing that iron was used sporadically during the Bronze Age (in this case just a couple of centuries before its end, and the Iron Age proper began in that region)— but how they figured this out is also pretty cool.

The dagger is 34 centimeters long, and has a gold handle with decorations. The blade is clearly iron of some kind, but IDing it as meteoritic has been difficult. Most methods involve getting a sample and destroying it (vaporizing it, for example), which is a problem when you’re dealing with a priceless artifact.

In this case, though, they used a non-destructive technique called X-ray fluorescence (or XRF) spectroscopy. This beams high-energy X-rays at the sample, which strips some of the atoms of their electrons. Other electrons then move around to fill the hole left behind, and emit X-rays when they do. Different atoms emit X-rays with different energies, and new detectors in portable XRF spectrometers are sensitive enough to taste those X-rays and sort them by their energies.

X-ray spectrum of the dagger
The X-ray fluorescence spectrum of the dagger, showing the presense of iron, nickel, and cobalt.

Daniela Comelli et al, from the paper

That plot shows the X-ray spectrum they found for the dagger. Each bump is energy emitted by a different kind of atom: iron (Fe), cobalt (Co), and nickel (Ni). Each atom emits X-rays at different energies, so each bump (technically, we call them “lines”) has its own name; thus Fe alpha, and so on. The size of each line depends in part on the amount of material present, so by carefully measuring the lines the percentage by weight of each element can be found.

They determined the dagger is about 88 percent iron, 10.8 percent nickel, and 0.6 percent cobalt. This is very much what you’d expect from a meteorite, and very different from terrestrial iron ore.

That confirms the metal from this dagger used to be part of an asteroid circling the Sun which fell to Earth some time ago. How cool is that?

meteorite letter opener
My own, decidedly much less pharaonic, letter opener from space.

Phil Plait

But you can tell more. The specific ratios of those metals can tell you which meteorite it was, or at least narrow it down. The scientists compared their results to meteorites from within a 2,000 km radius centered near the Red Sea, and found a near match in a one-kilogram meteorite called Kharga, that was discovered in 2000. It’s not a perfect match, but it’s close enough to indicate that such objects were available to the Egyptians.

It’s been known for some time that ancient peoples used meteorites for iron, which makes sense in hindsight*. Meteorites fall from the sky and land on the ground, where they’re easy to pick up and use. They’re unusual looking, so likely to be found by a curious passerby, and obviously denser than other rocks so that they’re bound to be kept and even cherished.

Working the metal is difficult, though, and Tut’s dagger was worked with some skill, indicating that even in the 14th century BCE ironmongers had some practice.

I find this whole thing pretty wonderful. I’m fond of talking about how astronomy is not some remote field of science, but has an actual, physical connection with people. It also gives us insight into our ancestors millennia ago. When we look out at the stars, we are actually looking inward at ourselves. The Universe has shaped us and our civilization, and it has been our use of science that has led to understanding just how profound that impact has been.

Top o' the sarcophagus lid to Boing Boing.

* Of all things, my first exposure to this idea was reading Philip José Farmer’s Riverworld science fiction series. Learning comes in all forms. 

June 1 2016 11:30 AM

Texas Rep. Louie Gohmert Will Save Us From Gay Space Colonies

Are you sitting down? Good. Comfy? Excellent. I wouldn't want you to be hurt when your jaw hits the floor watching this video. Texas Rep. Louie Gohmert, everyone:

Just in case you missed —and how could you?— here’s the fun bit:

I really wonder how many people in this body who had the ultimate power to decide whether humanity would go forward or not, whether there was an asteroid coming or something that would end humanity on Earth as dinosaurs were ended at one time--okay. We have a spaceship that can—as Matt Damon did in the movie—plant a colony somewhere. We can have humans survive this terrible disaster about to befall. 

If you could decide what 40 people you would put on the spacecraft who would save humanity, how many of those would be same-sex couples? 

You are wanting to save humankind for posterity—basically, a modern-day Noah. You have that ability to be a modern-day Noah. You can preserve life. 

How many same-sex couples would you take from the animal kingdom and from humans to put on the spacecraft to perpetuate humanity and the wildlife kingdom? 

That is why it has been called part of the natural law, natural law given by the Creator; but when we continue to abolish the first words of the Bill of Rights—the First Amendment—and we continue to prohibit the free exercise of religion, we don't have much longer to go. 

I’m not sure what’s more worrisome: That Gohmert seems so very concerned about gay space colonists in case of planetary armageddon, that he thinks his own religion is exempt from the First Amendment, or that, in 2016, a sitting member of the United States House of Representatives thinks that being gay or transgender is a “mental disorder” and “perverse.”

This might be a good time to note that elections have consequences. You put people in power, and they make laws. What they base those laws on might be their desire for religious oppression, their homophobia, their racism, their desire to please the people who fund them, or their simple desire to seize power and maintain it.

For example, in 2002 Texans elected Tom Delay, who became the House majority leader. He then led an effort, sadly effective, to gerrymander Texas District 1, which had been historically Democratic. It became heavily Republican, and Gohmert was the beneficiary of that action. Much to our nation’s embarrassment.

Elections have consequences. Choose carefully.

Tip o’ the gay spacesuit helmet to Brian Gaensler.

Update, June 1, 2016: In the perfect timing department, I just found out right after publishing this that June 2016 has been declared LGBT Pride month by President Obama. I'm guessing Gohmert won't be attending the parade.

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