Bad Astronomy Blog
Today is the day after American Thanksgiving, considered to be the first shopping day of the Christmas season. Due to the onslaught of eager shoppers to stores, it’s been nicknamed Black Friday.
It’s not restricted to the US, though. The Curiosity rover is having its own Black Friday on Mars — in this case, a bit more literally: It’s reached the edge of the Bagnold Dunes, a windswept region in the vast Gale Crater with huge, towering dunes.
The image above was taken Nov. 25, 2015 (also called Sol 1174 — a “sol” is a day on Mars, which is about a half hour longer than an Earth day, and Curiosity has been on Mars for 1175 sols as I write this). Look at it! You can see the flat, grayish rocks in the foreground, and distant hills in the background, but the view is dominated by lush, gorgeous, rippling dunes (check out this mosaic of images showing a much wider angle, too, because wow).
The dunes are dark, likely due to the sand being basaltic — a dark rock created when lava cools. Over billions of years, the exposed Martian basalt has eroded, creating grains of sand that can be blown around by the wind. But not easily!
Mars has an atmosphere, but the pressure at the surface is less than one percent that of Earth. It has winds, but even though they can move rapidly, the air is so thin they don’t have much force to them. Still, it’s enough to blow around the ever-present Martian dust (made mostly of iron oxide, giving it a pinkish-red color… after all, it’s rust!), and finer grained sand particles.
Dune fields litter the surface, but a lot of them are inactive; the wind there isn’t enough to move the sand around. But some fields are active, and the dunes can be seen to move over time. At Bagnold, the dunes migrate at roughly 0.4 meters per year — a little over a foot annually. That’s not much, but it’s measurable.
These dunes are a juicy target for Curiosity. It’s the first time an active extraterrestrial dune field has ever been examined in situ, for one. For another, examining the material will tell scientists on Earth what minerals are in the sand, of course. Measurements from orbit show that there appear to be some minerals located in some parts of the dune field but not in others. Why?
Also, as wind blows the grains it sorts them naturally by size. The distribution of grain sizes around the dunes will indicate how the winds blow, how the grains deposit onto the ground, and more.
The dune field is pretty big, kilometers across. It’s right on the path of the rover, near the foothills on the northwest flank of Aeolis Mons, aka Mt. Sharp, Curiosity’s eventual goal. It’ll have to cross the dunes to get to the mountain.
I’m personally thrilled by this shot, and I’ve been waiting for this for a long time. I love dunes on Mars! They’re spectacular, and fascinating.
But more than that, they’re so Earth-like in so many ways. The shapes — horseshoe-shaped barchans dunes, or the more stereotypical transverse dunes in the picture above — look achingly like those on our own fair planet.
Mars was once wetter, warmer, and had thicker air. Now it’s all gone. That’s because of eons of pummeling by the solar wind, the flow of subatomic particles from the Sun. The Earth has a magnetic field, protecting us from that, so we’re still warm and wet, even after 4.56 billion years.
If you want to be thankful for something, be thankful for that. And also that in some places, Black Friday is actually and truly a beautiful thing.
There’s a very long list of things I feel thankful for this holiday, far too many to actually itemize. But somewhere on that list, well above the median line, would be these goofy creatures:
We moved out to the country outside of Boulder a little while ago, and there was some extra space in the yard where the previous owners of the house had a small horse barn. We had no use for it, really, and couldn’t decide what to do with it. Then one day we were watching adorable goat videos, and my wife got this look in her eye…
And that’s how I became a goat person. We have two Nigerian Dwarfs and two pygmies. We picked up Clayton Forrester, one of the Nigerians*, when he was still being weaned, so we bottle-fed him goat milk for a week or so. He still likes to sit on our laps and cuddle while he chews his cud. It’s ridiculously cute:
Seriously. C’mon. There's also this.
I post pictures and videos of these dorks all the time on Instagram; follow me there if you want to see them. And you do.
I love these silly animals, and I love to share their antics with people online. It may not save the world, but you know what? Every little bit of joy we share, no matter how small, incrementally makes the world a better place. If a million people do that, even once or twice a week, it would add up.
Happy Thanksgiving, folks. Make the world better, even just a little.
* The other goats are Jack, Batman, and Sam. Someone asked me if Jack and Sam were from Stargate SG-1, and I could've kicked myself for never seeing that. But no, Jack is actually Jack Burton, from the single greatest movie ever made. I like to think that Clayton is named after a character in another favorite movie, but my daughter named him, so it's probably for this guy.
This week marks the (very round number) anniversaries of two of the most important scientific papers ever published.
One you’ve heard of—or at least, you’ve heard of the author and its concepts. The other you probably haven’t. Yet it is equally as important, and tells as great a tale.
First things first: On Nov. 25, 1915—100 years ago Wednesday—Albert Einstein submitted a paper to the Proceedings of the Prussian Academy of Sciences in Berlin titled, “Die Feldgleichungen der Gravitation,” or “The Field Equations of Gravitation.”
If that doesn’t sound familiar, maybe it would help if I said that this paper laid the groundwork for Einstein’s General Theory of Relativity.
Oh, right. That paper.
Einstein published his Special Theory of Relativity in 1905. That groundbreaking work showed that space and time were relative, and that if you moved near the speed of light relative to another observer you’d see these two properties very differently. Since then, the Special Theory has since been experimentally verified countless times.
After publishing it, Einstein started working out how to add gravity to this mix. That’s extraordinarily difficult, and the math fiercely complicated. It took him many years, but he submitted the paper in November 1915, and it was published in the next month. In it, he made a startling and fundamental claim: Gravity is not really a force as had been thought, but instead is a warping of space caused by matter.
Sound esoteric? Well, that’s because it is, a bit. Centuries earlier, Isaac Newton had proposed his theory of universal gravitation, describing gravity as a force, attracting one object to another. It depended on their mutual masses and distance from each other. Newton’s idea works pretty well, and in fact we still use it today to plot courses for spaceships!
The term “force” is difficult to accurately define in layman’s terms,* but you can think of it as some sort of connection between objects, attracting them or repelling them. That’s how Newtonian mechanics works out.
But Einstein’s General Theory changed all that. He found that gravity is not a force between two objects, but a property of space itself, a geometric bending or warping of it. It’s usually described this way: Matter tells space how to bend, and space tells matter how to move.
It was a fundamental shift in how we thought of space and matter, and fit right in with Einstein’s previous Special Theory work in showing that space and time were connected. Their implications are wide-ranging as well; for example, the solutions to these General Theory field equations describe the structure of space, and naturally predict the existence of black holes. They also predict the existence of gravitational lensing (which we’ve seen, and which led to a confirmation of the existence of dark matter), gravitational radiation (which we’ve detected indirectly), and gravitational time dilation (which we’ve also seen).
An even more profound impact of these equations is that they lead the way to understanding how the Universe itself formed and evolves, and even of its ultimate fate.
Heck, without the General Theory your map app wouldn’t work!
So, yeah. It’s kind of a big deal.
The second anniversary we’re celebrating now is no less in stature, and has an equally deep practical impact on the world.
One hundred fifty years ago, in late November 1865, James Clerk Maxwell published his paper called “A Dynamical Theory of the Electromagnetic Field,” and in it he wrote down a set of equations we now call Maxwell’s equations, which should hint at their importance. Why? They describe how electricity and magnetism are two sides of the same coin, actually the effects of a single force called electromagnetism. Up to that point they were treated separately. Maxwell united them.
The importance of this can’t be overstated! His equations show that electricity can be used to induce magnetism, and vice-versa. We generate electrical power based on this.† He showed that light is itself a wave, traveling through space as an oscillating electromagnetic field. Ever heard of the electromagnetic spectrum? Yeah. That’s from Maxwell. His equations show how light behaves, and in fact you can derive the speed of light from these equations if you can measure some other fundamental properties of space.
It is no exaggeration to say that Maxwell’s equations are at the very foundation of our modern civilization: computers, electrical systems, global communication—all of this comes straight out of these equations. Einstein’s ideas about relativity derive from them as well.
But there’s more to this story. Maxwell wasn’t a university scientist, working under a research grant to investigate the disparate fields of electricity and magnetism. Nor did he set out to revolutionize the entire planet’s civilization. He was just a curious person, someone who delighted in nature, who was puzzled by how it works, and who wanted to understand it.
And this led to the economic basis of a world.
This story is lovely and wonderful, and was best told by Carl Sagan in his opus, The Demon Haunted World: Science as a Candle in the Dark. I strongly urge you to buy and read that book; it’s magnificent, and many (including me) consider it Sagan’s best work. In one chapter, he talks about Maxwell and his equations, and it’s a paean to allowing scientists to study the Universe unfettered by politics (academic or governmental), allowing their imaginations to guide them.
In many fields of science there must be moral and ethical guidance, of course, but in theoretical physics it is the math and physics themselves that are the guide. Maxwell followed them and revolutionized a world. Einstein followed them and revolutionized our thinking about the Universe.
And today we celebrate the anniversary of both.
* Although, in this case, one could quote Kenobi et al., 1977: “[A force] surrounds us and penetrates us; it binds the galaxy together.” While widely admired and quoted, many find Kenobi’s dabbling in mysticism a bit off-putting.
† To be fair, scientists before Maxwell knew that electricity and magnetism influenced each other, but Maxwell quantified it, defined it, and it’s from there that our modern power systems are derived.
Jeff Bezos’s rocket company Blue Origin just surprised everyone by revealing their New Shepard* rocket reached an incredible milestone yesterday: In a test run, the rocket took off vertically, reached space, then landed again vertically minutes later.
The rocket launched from their site in west Texas, accelerating to a top speed of about 4600 kph, and achieving an altitude of just over 100 kilometers, the technical height defined to be the start of space (called the Kármán line). They also deployed the crew capsule at a height of about six km above ground, which parachuted safely back to Earth.
Blue Origin put together a nice — if somewhat misleading — video of the event. I say that because in the middle of the real footage they inserted CGI animation of a crew inside the rocket’s capsule; this was an uncrewed flight. Still, the video is cool:
I like the shots of the landing from various angles at the video’s end; it looks more like a Hollywood scifi movie than reality! But real it is. The descent is unnerving; the rocket engines don’t reignite until it’s only about 1600 meters above the ground, and it decelerates pretty hard. That saves a lot of fuel and makes perfect sense, but it’s a little scary to see it! Still, the rocket performed extremely well, and landed only a little over a meter from the center of the launch pad. Amazing.
Blue Origin attempted a similar test flight in April 2015, but the landing system hydraulics failed and the booster crashed. Apparently, and happily, this issue has been addressed.
So congratulations to Jeff Bezos and his team on this incredible test! This is very exciting to see.
However, I’m seeing some confused coverage of this event, and I want to clear a couple of things up.
First, yes, this launch is a big deal! It shows that Blue Origin is making excellent strides towards commercial space launches, a field currently dominated by SpaceX. Getting up to the Kármán line is a major achievement at all, let alone successfully deploying the capsule and then landing the rocket again. SpaceX itself is based on the idea of competing against big government contractors, so competition for them is good.
Bezos himself took to Twitter to announce the success, and made a subtle dig at Elon Musk and SpaceX at the same time:
I smiled, but I have to point out that, as great a technical achievement as this was, what Bezos has accomplished here is quite different than what Musk has been attempting.
The Blue Origin New Shepard is a suborbital rocket, designed to go straight up into space and back down again. The SpaceX Falcon 9 is an orbital rocket, which takes vastly more energy (in other words, much higher speed) to achieve its goal.
Musk responded on Twitter pointing this out:
He’s right. Landing a booster from an orbital flight is hugely harder than from a suborbital one. For orbital flights, the booster not only has to move far faster, it also will have a large horizontal speed relative to the ground to get to orbit, so slowing it is more difficult as well. SpaceX has not yet achieved a successful landing this way, but what they’re doing is literally an order of magnitude more difficult than what Blue Origin did.
Then, in my opinion, Musk made something of an unfair comparison himself. He tweeted:
True, but Grasshopper (a test vehicle designed to launch and land vertically) only got 744 meters above the ground, wasn’t designed for high-altitude flights (it’s a testbed for the F9 landing tech), and didn’t deploy a capsule. The later F9R tests based on Grasshopper were very successful as well, but only got a kilometer off the ground. What Bezos did yesterday was far more technically difficult.
Update, Nov 24, 2015 at 18:00 UTC: Musk has continued to tweet about this, correctly pointing out that suborbital flight and landing has been done before by SpaceShipOne and arguably the X-15 rocketplane. Musk also noted the series of water landing attempts using the F9 booster.
Mind you, suborbital flights are important. It’s more than just a tourist attraction (though a pricey one); real science can be done on such flights, even though weightlessness only lasts a few minutes. Blue Origin looks to be getting quite close to having the ability for these kinds of launches.
The company is known for secrecy, tending to announce achievements only after they’ve been reached. That’s understandable, and it can work to Blue Origin’s advantage in the media as a tortoise-and-hare story (one I think Bezos is happy with). That means details about their future goals are unclear, but the goal itself is obvious: getting in on the lucrative orbital satellite market as well. As I pointed out, the physics of this is quite different, and it’s a long journey there… but they just took a solid step in the right direction. Up. And back down again.
Correction, Nov. 24, 2015: I originally misspelled the rocket as New Shepherd; but it's punningly named after Alan Shepard, the first American in space.
Pluto is an odd little beast.
You knew this, if you’ve been paying attention at all these past few months. But one thing that struck me recently is its 6.4-day rotation rate. That’s weird; most free bodies in the solar system spin either much faster than Earth or much slower. Jupiter, Saturn, Uranus, and Neptune have days that are shorter than Earth’s, ranging from 10 to 17 or so hours. But Mercury takes 60 days, Venus a whopping 243 days. Mars spins at almost the same rate as Earth, with a day 24 hours 37 minutes long.
So Pluto’s week-long spin is an oddity. If you could watch it, what would it look like?
Well, it would look like the photo at the top of this post. Those images were taken by the New Horizons probe as it passed Pluto in July 2015. As the spacecraft approached, it took a lot of snapshots of the little world, and over time was able to see it at various points in its day. These were collected, scaled to the same size, and arrayed to show a day in the life of the frozen iceball.
Each shot shows the highest-resolution image taken for that particular point in the day. The shot at the 3:00 position was taken from farthest away (about eight million km), and the one at the 6:00 position was the hemisphere seen by the probe when it passed a mere 12,500 km over the surface.
You can see the familiar heart-shaped Tombaugh Regio, a flatter region that is covered in nitrogen ice (the left lobe, Sputnik Planum, is much smoother than the right lobe). I like how you can see different resolutions blurring the features at different times; it is physically showing you what can and cannot be seen clearly during various points in the flyby.
Charon, Pluto’s outsized biggest moon, orbits the world in that same 6.4-day period, and also spins at the same rate (this is not a coincidence). The New Horizons team also put together a similar mosaic for Charon:
I’ll be honest: Despite the somewhat lower contrast and details, I like this one better. I think it’s because the north pole of Charon is so clearly marked by the dark spot nicknamed Mordor Macula. It’s not clear why Mordor is dark (and red), but it may have to do with organic molecules from Pluto raining down on it.
Geez. Pluto and Charon are weird.
Which brings me back to the length of the day/month there. Charon and the littler moons may have formed by a huge impact; a big chunk of ice and rock smacked Pluto hard long ago, and the debris coalesced to form those moons. The impact could have changed Pluto’s rotation rate, and then tidal interactions with the newly-born Charon would have modified it as well. Once everything locked into place, we got this week-long spin of the three systems (Pluto itself, Charon itself, and the two together orbiting each other).
Most small objects in the solar system have had their spin rate modified. Earth spun much faster before our own Moon formed in much the same way as Charon. Venus spins slowly and backwards, so it may have been flipped over by an impact (or some other process we haven’t quite figured out). Mercury’s proximity to the Sun played havoc with its spin. Asteroids spin up due to sunlight.
So perhaps Pluto isn’t all that odd after all. It’s actually quite normal in its weirdness… or, at least, that’s my spin on it.
The saga of The Man In Congress In Charge of Science But Who Doesn’t Understand It continues.
For those new to this, Congressperson Lamar Smith (R-Texas) — Chairman of the House Science, Space, and Technology Committee — doesn’t think global warming is real. He thinks it’s a huge conspiracy by climate scientists who fudge the data to make it look like the planet is heating up, because Obama.
I wish I were being hyperbolic. But this is literally true.
In Part 1 of our tale, Smith subpoenaed Kathryn Sullivan, the administrator of the National Oceanic and Atmospheric Administration, claiming that scientists in her agency were “altering the data”. Smith got this idea after a paper was published in Science showing that the global warming “pause” so lauded by climate change deniers didn’t, in fact, exist. This research was done by a team of NOAA scientists and, I’ll note, is correct. The “pause” isn’t real.
That didn’t stop Smith. He also demanded the data, methodology, and emails of NOAA scientists be released (despite the first two already being publicly available). We also learned that Rep. Eddie Bernice Johnson (D-Texas) — who is the senior Democrat on the Committee — sent Smith a letter accusing him of harassing and second guessing scientists, and also pointed out he’s not qualified to assess the data or methods. This, too, is correct.
In Part 2, Smith made public his conspiracy theories about scientists fiddling with the data (they did this, Smith claims, “to advance this administration’s extreme climate change agenda”, in case you were wondering just how far removed from reality Smith is on this), and I showed why these ideas are nonsense (to be very very very very polite). In Part 3 I went into more detail, showing that Smith doesn't understand even the most basic principles of scientific data measurement.
And now here we are, at Part 4 of a presumably infinite series. His new claim? That the NOAA Science paper in question was rushed into publication, and that Smith has “whistleblowers” who will attest to it.
However, that’s at odds with the facts. Rep. Johnson wrote yet another letter to Smith, outlining where his claims are clearly wrong. She lays out a timeline, showing that the paper was submitted to the journal in late 2014, and took months to publish. Not only that, it relied on data from papers submitted to the journal in 2013 — hardly a rush job.
I’ll note that these alleged whistleblowers had ample opportunity to file a complaint with the NOAA itself. Yet no complaints have been registered (even though the NOAA has an obvious and easy-to-find scientific integrity policy).
Not only that, Smith has sent several letters to the NOAA and other groups — seven in total — with his demands, but only just now, in his most recent one, did he mention whistleblowers. That’s curious; Johnson has asked him repeatedly why he thinks the scientists have fiddled with the data, but he’s been silent on that.
It’s also curious, as Johnson notes, that Smith has declined to share any of the information about his alleged whistleblowers with any of the Democratic minority on the committee. If he’s not purely politically motivated, why wouldn’t he give this information to them? Who are these whistleblowers? What are their specific claims? Why has Smith waited so long to mention them?
I strongly urge you to read Johnson’s letter; it really shows that Smith’s actions are the results of political grandstanding. The NOAA had been complying with his requests, as silly and wasteful as those requests were, but Smith ignored this and kept making more and more unreasonable demands. Finally, the NOAA put their foot down; NOAA Administrator Sullivan has refused to comply any further.
I’ve been saying that Smith is harassing scientists, and he’s abusing his power of Congressional subpoena. Now we have even more evidence: He’s been pressuring Commerce Secretary Penny Pritzger over all this, trying to get her to in turn pressure the NOAA to turn over the scientists’ emails. If NOAA doesn’t comply, he’s threatened to subpoena the Secretary herself.
Not only that, but his threats of Sullivan are atrocious. As Johnson points out, in what may be my favorite part of her letter:I think it might be informative to take note of whom you are threatening. Dr. Kathryn Sullivan is PhD [sic] geologist, former naval reserve officer, former three-time NASA astronaut, former chief scientist of NOAA, and former member of the National Science Board. As an astronaut, Dr. Sullivan became the first American woman to ever “walk” in space. Dr. Sullivan is the very definition of service to country, and she is a role model for us all. I highly doubt Dr. Sullivan is intimidated by your threats, but it is an indication of how low the Majority is willing to stoop to perpetuate their anti-science agenda when a legitimate American icon is dragged through the mud in furtherance of an ideological crusade.
Smith is out of control. I earlier likened him to Senator Joseph McCarthy, who, in the 1950s, went on a huge and reckless witch hunt, looking for Communists in government, running people’s careers and lives in the process. That likeness grows ever clearer into focus.
I don’t see any reason to change my assessment of Smith now. He is a demagogue, using and abusing his power to stifle scientific research, to create a climate of fear and pressure for those scientists, and to obfuscate and further cast doubt in the public’s mind about the reality of climate change and its effects (an effort which has of course found purchase with the usual right-wing media suspects).
This behavior is as appalling as it is damaging and clearly based on falsehoods. The world is warming up. We are seeing the effects of that now. And we know that it’s because of the damage humans are doing, pumping billions of tons of carbon dioxide into the air every year. These are facts.
But the majority Republican Senators and Congresspeople in charge of critical committees reject these facts, replacing them with their own fantasies of conspiratorial scientists. These people are putting our nation’s security at risk. It’s good news that some of the GOP in Congress are willing to be swayed by facts, but the sad and embarrassing truth is the ones in key positions are not. And while they fiddle, the world burns.
Well, this is cool: Astronomers at the Ruhr-Universität Bochum in Germany have created a ridiculously huge 46 billion pixel map of the sky! According to the press release, it’s the largest astronomical picture ever created in terms of pixel size (I have not heard of any larger, for what it’s worth).
Even better? It’s interactive. You can pan around, zoom in and out, and fiddle with the colors, too.
Here’s the link to the map. But, a couple of caveats. It’s not lightning-fast; I had to wait many times for it to load (I checked; my download speeds are around 20 Mbps). Also, without instructions it’s a little tricky to use, but if you play with it for a while you’ll get the hang of it. You can also type the name of an object into the finder box on the lower left; try “M 20” (the Trifid Nebula, screenshot shown below), “eta car” (for the bright star embedded in the Carina Nebula), or “M 16” (the Eagle Nebula, shown at the top of this post). By the way, nebulae appear green due to the filters they used to make the map.
The map isn’t of the whole sky; it’s actually a series of fields located along the plane of our Milky Way galaxy. Still, the numbers are impressive:
- Total number of fields making up the mosaic: 268
- Area of sky covered: 6° x 220° for a total of 1323 square degrees (that’s over 6500 times the area of the full Moon on the sky!)
- Total file size: 194 Gigabytes
- Total number of stars: Around 16 million
- Number of variable sources: 64,151
That last one was part of the reason why they did the survey. Here’s the scoop: The observations were made with a pair of small, 15-cm (6-inch) robotic telescopes located in Chile. Each ‘scope has a very wide 2.7° field of view, and they observe each of the 268 fields roughly once per month. They can detect stars down to about 18th magnitude, which is pretty faint: the dimmest star you can see with your naked eye is about 60,000 times brighter!
Many surveys go fainter, but then bright stars tend to blow those observations out. This survey was done specifically to reach middle brightness stars at high enough resolution to distinguish tightly spaced objects well.
By spreading out the observations over time, they can detect objects that change brightness. Some stars are variable, getting brighter and dimmer with time. Others are in binaries where one star blocks the other every orbit (called eclipsing binaries). Stars explode, asteroids fly by, and so on.
Analyzing this new dataset for his PhD work, Moritz Hackstein found a total of 64,151 stars that changed their brightness, and nearly 57,000 of them were previously unknown! That’s pretty astonishing.
Surveys like this are precious and valuable. If an object changes catastrophically, we only get one chance to observe that event. This survey keeps a record of everything that happened in that section of the sky for nearly five years.
It’s also just fun to play with. I enjoyed scanning along its length, trying to see how many objects like nebulae I could identify. Only one big one stumped me (the Running Chicken nebula, yes, seriously), but a couple of bright stars got past me, like Alpha Centauri.
It also gives you a sense of just how flippin’ huge the sky is. Zoom in, zoom out, pan around, but bear in mind: The total sky is about 40,000 square degrees. This map is therefore only about three percent of it.
There’s still a lot more to see.
Nobody’s perfect. Some people come closer than others, but that’s usually because of good editing. In my case, I have proof: Here’s the fourth Crash Course Astronomy blooper reel, showing that we don’t just bang these episodes out. We have to edit them a lot.
Ironically, even these outtakes are edited; not all of them are funny. My editor Nicole Sweeney, only picks the ones that a) make her laugh, and 2) make me look like a dork. Her job is way too easy.
Can’t get enough of this sort of thing? Then watch the first, second, and third blooper reels, too. And all the currently aired episodes of Crash Course Astronomy are available in one easy-to-binge list. Ten straight hours of astronomy!
Regular readers know how much I love a) clouds, and 2) optical phenomena in the sky, so I can say with complete honesty that this is by far the coolest pileus cloud with iridescence you’ll see all day.
Right. You’ll probably want some details.
This photo was taken by Beckie Bone Dunning on Oct. 29, 2015 when she was in Jamaica. There were storm clouds approaching, almost covering the Sun, when she snapped this shot. Being the huge dork that I am, I knew right away what was what here.
First, the colors are from iridescence, a complicated physical phenomenon. I’ve written about this before:Iridescence is a weird phenomenon. You need lots of tiny raindrops (or ice crystals) all the same size over a large portion of the cloud. In a rainbow, the lights goes into the droplets and gets bent (twice) to create colors. In iridescence, though, the light actually bends (diffracts) around the droplets. Different colors bend by different amounts, splitting the colors apart. The size of the raindrop needs to be roughly the same size as the wavelength of light, so when I say “tiny” I mean it: The drops must be less around a micron in size! A human hair, by the way, is about 100 microns in width, so these really are teensy drops. But it’s more complicated than just that. The cloud also has to be what’s called optically thin; that is, mostly transparent so that on average a beam of light only hits one droplet and only gets bent once. If it hits multiple drops the colors get washed out. That’s why this happens more often near the edges of clouds, where they’re thinner. On top of that, the light waves interfere with each other, similar to how waves in a bathtub add together or subtract from each others’ wave heights as you wiggle around (and please, don’t deny you’ve ever done this playing in the tub; it’s fun, and educational!). These processes combine in complicated ways to produce these different colors.
Note that the colors in iridescence are different than the ones in rainbows because they're generated in a different way; you can get teal, pink, and more from iridescence.
So that explains the colors. What about the weird, twisty shape?
Ah, that’s because this isn’t just a cloud, it’s a pileus cloud. These are thin, cap-shaped sheets of cloud that form above rapidly rising columns of air. For example, in a cumulonimbus cloud, the shaft you see is due to the warm air rising, which usually bubbles into that cauliflower-shape head at the top. If there is a humid layer of air above it, the rising air will push it up (like a fist pushing through a rubber sheet), where it expands and cools. If it cools below the dew point, droplets form, and you get a pileus cloud.
Pileus clouds are thin, and have tiny water droplets in them. Perfect to make iridescence! You have to be at the right spot to see them, when the clouds are near the Sun… which is exactly where Dunning was. Voilà.
Amazing. I’d LOVE to see something like this. I’ve seen both pileus and iridescence before, but never at the same time. I’d expect it’s rare where I live; we tend to get cumulonimbus clouds forming to our east, as air rises over the Rockies and picks up moisture as it crosses the plains. That happens in the afternoon, when the Sun is to the west, so they happen in opposite spots in the sky. Ah well.
But that arrangement does supply us with a lot of rainbows, so I can be pretty happy with that, too.
More cool weather stuff:
Tip o’ the nebular hat to Jacob Black.
Because why not, here are two glorious spiral galaxies to brighten your week.
The first image is by my friend Adam Block, and it shows NGC 488, a tightly-wound spiral about 100 million light years away. I love how delicate it looks; the blue arms are well-separated but fluffy; I’d almost call this a flocculent spiral.
The inner region is very interesting; it’s much redder, which generally indicates the presence of older stars — blue stars are very massive and don’t live long, exploding as supernovae after only a few million years or so. That leaves longer-lived redder stars behind, so where you see big red regions you’re usually seeing a place where stars haven’t been born in a long time.
It’s interesting that you can still see a spiral pattern in the red inner region, and a clear set of dust lanes as well. Thick dust is dark, blocking light behind it. Thinner dust, though, can scatter away blue light (like the Earth’s air does to sunlight, making the sky blue). I wonder if there’s just a lot of dust spread around that inner region of the galaxy, reddening it. A quick literature search didn’t turn up anything, though.
Either way, I strongly urge you to check out Adam’s larger and higher-resolution image of this object. It’s stunning, with bright stars and scattered background galaxies, with some of the latter many hundreds of millions or even over a billion light years away. It’s gorgeous.
Speaking of gorgeous, the second image is of M 94, a much closer spiral at about 16 million light years distant. Hubble observed it, showing just the inner region, producing this spectacular image:
That ring of blue stars is real; M 94 seems to be producing a lot of young stars in a circular region around the nucleus. The size of the ring indicates it may be due to a resonance phenomenon, forcing gas clouds and stars orbiting the galaxy at that distance closer together. It’s a bit like pumping your legs in time with swinging on a swing, forcing your arc to go higher; in this case it has to do with the gravity of the rotating galaxy as a whole “pumping” the orbits of objects within it. Anyway, it causes gas clouds to collide, collapse, and form stars.
That becomes a little more obvious in another shot of M94 from Hubble… well, actually the same shot, but this time including colors that highlight the presence of those gas clouds:
Astrophotographer Robert Gendler put this shot together, and he included some data from the Subaru Telescope as well. The pinkish-red is emitted by the gas clouds, and the blue color of the young, massive, and very hot stars is a lot more obvious.
Man, I do so love splashy spiral galaxies. The science and physics involved in their structure is both powerful and sublime, and their beauty… well, that’s tough to match.
Want to learn more about spiral galaxies? Then do I have a Crash Course Astronomy episode for you!
It’s been a while since I’ve written about Bobby Jindal. He’s the governor of Louisiana, and until yesterday was one of the countless people running for President under the GOP banner.
He is not exactly a steely-eyed promoter of science, just as I am not exactly a fan of his. So I was pretty happy to see him roundly mocked by Jimmy Fallon and Aziz Ansari on The Tonight Show last week:
The best part happens starting at 2:09, where they flay him for his anti-science views. I loved it, not only because it’s so well-deserved, but also because it saves me from doing it myself.
Oh, who am I kidding? Let me add a little bit here.
Jindal came to national prominence in 2009 when he was chosen to give the GOP rebuttal to a speech by President Obama about a stimulus package. He mocked the government for spending money on something as silly as volcano monitoring. Who could disagree with that? I mean, c’mon, how could anyone want to spend money on researching potentially huge natural disasters that might significantly destroy a large part of a state and kill thousands of people? Certainly that’s not something the governor of Louisiana could possibly endorse.
Over the years he’s rarely missed an opportunity to stomp on the Constitution that he took an oath to uphold. For example, he signed the blatantly terrible “Louisiana Science Education Act” into law, which allows creationism to be taught in public school (lest you think I exaggerate, Jindal admitted that’s what it does). This is a patently unconstitutional law, and every year hero-of-science Zack Kopplin has fought to get it repealed, but every year the creationists and other fundamentalists in the Louisiana government uphold it.
Unshockingly, he’s also a climate change denier.
So, yeah. Happily, his chance of getting the GOP nod for President was always essentially zero, and now is identical to it. That’s good. Even better, he won’t be Governor of Louisiana much longer; term limits means he’s out next January after an election later this month. Perhaps once he’s out of power, the damage he’s done can start to be reversed.
If so, then this too shall pass. Still, I hope history remembers him for all these outrageous and ridiculous stances… and also as the guy who said the GOP “must stop being the stupid party”.
Tip o’ the pistil to Ryan Bays.
One of the things I love about photography in general, and astrophotography in particular, is you never quite know what you’ll get.
Take, for example, Tim Ashby-Peckham, who saw that the International Space Station was going to make a nice pass of his location in the early evening of Nov. 1, 2015. He set up his Canon 70D camera on a tripod, aimed it in the right direction, and waited. Once the ISS came into view, he started snapping away.
Take a look at the photo above. You can see the ISS as a long streak, since it moves a lot during the 30-second exposure. But take a closer look. See the wiggle in the streak at the bottom?
Here, let me enlarge it (I’ve rotated the shot to make it easier to see, and inset a zoom on the piece in question):
Ah, see it now? Clearly, something whacked his tripod during the shot. Again, I’ve ruined many a fantastic photo doing exactly that with my foot (as has pretty much every photographer ever); it’s easy to do when it’s dark out.
But the wiggle doesn’t look like the usual foot-in-tripod result. That usually is more chaotic and has a sharper zig-zag to it, rather than the smoother back and forth seen here.
So what ruined his photo?
An earthquake. Yes, seriously.
Ashby-Peckham took this shot in South Auckland, New Zealand, around 8:57 p.m. local time on Nov. 1, 2015. At 8:58, a magnitude 2.2 earthquake hit a couple of hundred kilometers to the southeast.
Now, skepticism is called for here (the Reddit thread, where I first saw this, has a lot of back and forth about it). Could it be a coincidence? Sure, it could. My strongest doubt was that a quake that weak could be felt that far away. However, in an email discussion about it, Ashby-Peckham told me that another earthquake about the same distance away was indeed felt in Auckland. I’ve been in a couple of earthquakes that size when I lived in northern California, and they were enough to make my closet doors rattle.
From much farther away, it’s not out of the question that one that size could cause a small jiggle in a tripod. Remember, a tripod isn’t perfectly rigid, and it has the weight of the camera all the way on one end. Ask any photographer: A good breeze can cause the tripod to shake (though not likely in this case; the shaking started after the exposure began, lasted less than a second, and then nothing for the rest of the shot).
Usually, it’s maddening. In this case, it was literally Earth-shaking.
So this is a new one on me. Using the ISS as a virtual seismograph! It’s a pretty funny idea. I suppose if you live in a place with enough earthquakes you could actually calibrate your photography equipment to them, measuring how much the image wiggles versus size/distance of the quake. You need a moving target; stars don’t move quickly enough, and all you get is smeared-out disks for them (note that in the shot, the stars do appear to wiggle a bit). Of course, you could put the camera on a motor, letting it slowly scan the sky over and over again.
That seems like a lot of work, but maybe fun work. Or you could, y’know, just get a seismograph. Or just check the USGS quake page. That might work, too.
Tip o’ the lens cap to Peter Caltner.
I have some very good news about the War on Science: The recent Canadian election has kicked out a regressive government and put one in place that, all signs indicate, will be much more welcoming of reality.
The election of progressive Justin Trudeau appears to be a huge win for science. For one, it means Stephen Harper is out, and his oppressive anti-science tactics along with him. Under his rule a lot of research funding was cut, for example. Worse was the fact that scientists were muzzled; they literally were not allowed to talk to the press about any research results without a governmental say-so.
This is not a repeat from Soviet Russia. This was Canada, in the 21st century.
But it was true, emphasis on the word “was”. One of the first acts of the new Trudeau government was to allow scientists to speak freely to the press. This is an extremely important event! A government that controls what scientists say can also control the science being done, which can have dramatic and profound effects.
For example, imagine if climate scientists in the US were muzzled, only allowing climate change deniers access to the media. This is essentially what the previous Canadian government was doing.
But no longer. And that’s a very, very good thing.
And it gets better. Trudeau announced his new cabinet, and (besides it having male/female parity, as well as a diversity that far better matches that of the population) it includes a Minister of Science!
Wow. This is fantastic news. Harper had banished science oversight to a junior minister in the Industry department (part of an over-arching plot to relegate science to the services of industry, a shameful act I’ve written about before – twice in fact, since I got an earful of trivial propaganda from the Canadian government after my first article about it).
But no more. Science now has its own Ministry, and not only that, the Minister is a bona-fide actual scientist. Her name is Kirsty Duncan, and she is a medical geographer — she worked on tracing physical remains of the Spanish influenza epidemic that (almost literally) decimated the planet in 1918.
While Duncan will oversee the government’s role in pure science, there will also be a Minister of Innovation, Science, and Economic Development, Navdeep Bains, who will oversee the coordination of science and industry.
This is a very positive development. Science is way of finding knowledge that gets ever-closer to truth. It must be, by its very nature, an exploration of the Universe unfettered by political ideology or blinders installed by narrow-minded desires. If the research naturally goes that way, that’s fine, but science must inform politics, not vice-versa. Once politics starts interfering with science, well, that way disaster lies.
I’m glad the new Canadian government understands this. If only my own country’s majority party did.
I love it when a piece of news comes out that ties in so neatly with a recent episode of Crash Course Astronomy: Hard on the heels of my talking about clusters of galaxies in the distant Universe, astronomers have announced they’ve found an immense cluster 8.5 billion light-years away. It’s the most massive cluster found at this distance.
How massive? A quadrillion times the mass of the Sun massive. That’s equivalent to 10,000 galaxies like our Milky Way. That’s a huge honkin’ cluster.
The cluster is called MOO J1142+1527 (for “massive overdense object” plus its coordinates on the sky), and it was found as part of a project set out specifically to look for big galaxy clusters that are very far away. The project is called—are you ready for this?—Massive and Distant Clusters of WISE Survey.
Or, as I’m sure the astronomers involved prefer it to be called, MaDCoWS.
MOO J1142 was found in a search using NASA’s WISE (Wide-field Infrared Survey Explorer) observatory, which surveyed the entire sky in different wavelengths (colors) of infrared. Distant galaxies give off a certain ratio of infrared light, so the astronomers used software to look for objects with those color ratios. If it found any, it then checked to see if there were lots of such sources all near each other, which would indicate it could be a galaxy cluster. They found thousands of such groups, and MOO J1142 was one of the best.
Switching to Spitzer Space Telescope, they then got infrared images with higher resolution, so that individual galaxies could be better seen. Once they had that in hand, it was off to the Gemini North and Keck observatories to take spectra, which gave them the redshifts of the galaxies. The redshifts are an indicator of distance, and that’s how they determined these galaxies were so far away.
Finally, they used an array of telescopes called CARMA that looks at microwaves from space. Using a sophisticated technique (the Sunyaev-Zel’dovich effect, for those who are curious), they were able to map the gas of the cluster and determine its immense mass.
Sometimes, when we look at very distant objects, we find some that are a bit puzzling. Remember, when we look very far away, we’re seeing the Universe when it was younger. Sometimes we find galaxies billions of light-years away that are bigger than we’d expect given their young age—that means galaxies form and grow faster than we first thought.
I was completely expecting this to be the case for MOO J11452, too, because it’s so flippin’ big and so far away. But in fact, the MaDCoWS astronomers note in their journal paper that it’s within the reasonable limits of size and mass for its age (given how we think the Universe behaved when it was young). That was a fun surprise for me! I guess sometimes, not being surprised is a surprise.
They do also note that it is very large, and likely to be one of the most massive such structures at that distance or farther. That means it must be rare, and in fact, using some statistical analysis, they figure it’s likely one of the five biggest clusters more than 8.5 billion light-years from us.
In other words, we’re not likely to find too many more such distant beasts.
That’s amazing, too. We still have a vast amount to learn about our Universe, but in some cases we can be pretty sure we’re closing that gap. Finding such a massive, distant cluster is a big step, because there’s not likely to be many more. That makes it a fantastic laboratory for scientific exploration.
People sometimes ask me why I love science, but how can it be any other way? We’re literally looking across the entire Universe just so we can understand it better!
What’s not to love?
Here's the episode of Crash Course Astronomy I mentioned at the beginning of this article. Stay through to the end. You'll like it.
Over the past few years I’ve hammered pretty hard at Republicans in Congress for being anti-science because… well, because, as a party, they are.
But there’s dissension in the ranks, and I’m very, very pleased to hear it. And it’s over the single most important topic in the politicization of science: climate change.
There have been a few voices in opposition to the staunch GOP plank of head-in-the-sandism, but just a few. Lindsey Graham, for one, and Jon Huntsman for another (though Huntsman is a former governor of Utah, and not in Congress). I’ve also mentioned Kelly Ayotte (R-New Hampshire) before, who signed on with President Obama’s EPA Clean Power Plan.
But now it looks like they’re getting organized. In the Senate, Ayotte, along with Lamar Alexander (R-Tennessee), Graham, and Mark Kirk (R-Illinois) have formed a Senate Energy and Environment Working Group, the purpose of which is to “focus on ways we can protect our environment and climate while also bolstering clean energy innovation that helps drive job creation. The group will meet periodically to discuss general energy and environmental issues and exchange ideas about potential legislation.”
That is fantastic news! I also like that they are paying attention to “market-based reforms” when it comes to energy. Alternative energy sources (notably wind and solar) are getting cheaper very quickly, and in many places are on equal footing with the energy generation cost for fossil fuels. It makes good economic sense to invest in these sources, and that’s a powerful argument when it comes to the conservative party… assuming that fossil fuel money won’t always present a roadblock to the ones in power.
I have a lot of hope in people like Ayotte, who has a history of bucking her party when it comes to climate. Good on her.
There’s hopeful news on the House side, too. 11 GOP Representatives put forth a Resolution (H. 424), “Expressing the commitment of the House of Representatives to conservative environmental stewardship.”
The resolution reads pretty well to my eye, stating for example, that “it is a conservative principle to protect, conserve, and be good stewards of our environment, responsibly
plan for all market factors, and base our policy decisions in science and quantifiable facts on the ground.”
Nice. And true. Mind you, this is a resolution, not a bill, so it won’t be law or anything like that. But given how notoriously anti-science so many GOP Representatives are — like the Chair of the House Science, Space and Technology Committee — this resolution is very positive, very hopeful. As I read it, I almost felt like it was an act of defiance. It wasn’t nailed to the door of the Rayburn House Office Building, but its point is clear.
It’s too bad that the only two GOP Presidential candidates making any sense at all on climate — Graham and Pataki — are polling so low their numbers are indistinguishable from 0. I still think Trump and Carson will flame out, leaving Rubio or Cruz as the actual contender after the primaries… and both of them are deniers. Of the two, Cruz is more of a flat-out denier, but Rubio is no prize either.
The members of the GOP who accept reality have a long, hard struggle in front of them. And while I’m sure I’d disagree with them over many issues, global warming is one of if not the most important issue of our time. I will support them on this, and I am very, very happy to see them taking on this mantle.
I would very much love to see this no longer be a partisan issue. This affects all of us, and the future of our species for several hundred years at least. It’s time everyone in power took it seriously.
I’m kindof in awe over this news: On Oct. 27, 2015, NASA’s Swift satellite detected its 1000th gamma-ray burst!
That’s a lot of bursts.
Swift was launched in November 2004. It’s a relatively small and inexpensive astronomical observatory, designed to detect and rapidly target gamma-ray bursts (GRBs). These flashes of gamma rays baffled astronomers for decades; they were discovered in the 1960s, and it wasn’t until the 1990s that we finally figured out what they were: unbelievably powerful explosions marking the births of black holes.
I’ve written about GRBs quite a few times; here’s a quick overview that will terrify you about how much energy these hellish objects pack. Also by coincidence, this past week’s Crash Course Astronomy is all about GRBs:
Despite their enormous energy output, GRBs fade so quickly that it’s hard to observe them. Swift was designed specifically to nail down their coordinates in the sky, sometimes as rapidly as seconds after the initial flash. Swift quickly slews over to point its other telescopes at the burst, taking critical observations within a minute or two, and also improving the location measurement. The coordinates are beamed to the ground, sent to telescopes around the planet, which then (if they can) also observe the burst.
Before Swift it could take hours, days, or even weeks to get good follow-up observations of GRBs. Now it takes literally seconds.
The lucky 1000th burst — called GRB 151027B (the second GRB seen on Oct. 27, 2015) — is soul-crushingly distant, over 12 billion light years away. Most GRBs Swift has seen have been billion of light years away, in fact. That’s how powerful they are; visible across the vast reaches of the Universe.
Swift has shown us that a GRB pops up in the sky nearly every day. That means there are actually far more of them out there than we see! The emission is beamed, focused into a tight jet; we only detect a GRB if that jet is pointed right at us. For every one we see, there are many more pointed the wrong way. And in turn, this means black holes are being born all the time, somewhere in the cosmos.
How’s that for your thought of the day?
I had the privilege of working on the education and public outreach for Swift for several years, helping to write educational activities based on its science, web articles, and more. I wrote a bit about that on the occasion of Swift’s tenth anniversary in space.
Swift is one of my favorite missions of all time. It was brilliantly conceived, carefully built, kept at a low cost, and has worked almost flawlessly for over a decade, doing cutting edge science in a field of astronomy that didn’t even exist when I was born.
That’s quite a legacy. And it’s still going. Congratulations to everyone on the Swift team!
George Hrab is many things: A musician, a comedian, a fine dresser, and a very good friend of mine.
He’s also a skeptic, and an excellent storyteller.
Those last two are why I bring him up: He gave a TEDx talk about skepticism recently, and the video is now online. You really need to watch the whole thing; it’s only 24 minutes long, and it’ll fly by. That’s the same length as a standard sitcom, and trust me, it’s way better.
Or don’t trust me. That’s kinda the point.
There’s so much great stuff to take away from this talk, but my favorite is this quote (from the part starting at 12:57): “Every time you look on the web, every time you receive a piece of email… pretend it’s April 1st.”
If Every. Single. Person. Alive. Would just DO that, then my job load would be cut by 15 percent. Easily.
George’s talk is a tour de force of what it means to think. It should be required viewing in schools around the world.
This morning, just before 06:20 UTC and right on schedule, a small bit of space junk called WT1109F slammed into Earth’s atmosphere at nearly 40,000 kilometers per hour. The huge pressure generated as it plowed through the air heated it up, broke it to pieces, and it disintegrated.
We’re still not sure what it was, other than it was likely a piece of hardware from an earlier mission to the Moon. But we know for a fact it burned up: We have pictures!
The photo at the top was taken by a joint aircraft mission sponsored by the International Astronomical Center and the United Arab Emirates Space Agency. They were flying over the thick clouds covering the Sri Lanka coast and were able to get some pretty amazing shots of WT1109F as it came in. Here’s a brief video featuring a short animation and some of the photos:
Coooooool. That pretty much removes any doubt it was some human-made object; such things tend to break up and fall as parallel clusters of fireballs (for example, the Cosmos 1315 satellite, the Janice Voss ISS resupply ship, the Albert Einstein, and many others). That can happen with asteroids and other natural detritus, but not often, and it usually doesn’t look quite like this.
The weather prevented anyone from the ground seeing the event, but there are some reports of a loud noise around the same time. Of course, that could be thunder—like I said, the clouds were thick—but it’s possible it was the sonic boom from the debris as it passed through the air at hypersonic speed. I wonder if we’ll ever know …?
Sometimes, you have to be satisfied with not knowing. We may never find out exactly what mission this hardware was from. Science is like that. For every question we answer a hundred more pop up, and sometimes you just never know. The important part in this case is that the object was seen, it was identified in previous observations from years before, and that allowed an accurate orbit to be determined and a time of entry calculated.
Think about that! It was only rediscovered on Oct. 3, yet astronomers were able to pinpoint almost exactly when and where this thing would come down.
That’s astonishing. But then, that’s science.
Tip o’ the Whipple Shield to Jonathan McDowell.
More about WT1109F from shortly after it was discovered:
Back when I got my Ph.D. in astronomy, I was pretty focused on my own research topic. Still, I grew up loving astronomy, and I never lost the bug to learn about different aspects of it. For my degree I was studying an exploding star and had always been fascinated by apocalyptically huge explosions in space.
Thinking back on those days, I’m surprised I didn’t seem to know that much about gamma-ray bursts. These huge explosions in space are basically genetically designed to hit all my scientific sweet spots: They’re mysterious, they’re ridiculously powerful, everything about them is over the top, and they baffled astronomers for decades.
I’m not sure why I didn’t read much about them then, but that sure changed! They’re one of the most amazing kinds of events the Universe can muster these days. Even better? They’re the topic of this week’s Crash Course Astronomy:
I never did any scientific research on GRBs, but I’ve been involved with them for a while now. When I was working on Hubble I started getting really interested in them; I remember impatiently waiting on the data from observations of GRB 990123 taken by the camera I was working on. As soon as we got them, I pounced, processing them and creating an image of the explosion. I was stunned to see it sitting right on top of an odd, curved-V-shaped galaxy, clearly the host of the burst. Literally at the same time, my colleague Andy Fruchter (who did in fact study GRBs and was in charge of these Hubble observations) was also processing them, and he was the one to make the important announcement that the camera had clearly detected the host galaxy. It was extremely cool to have seen that data right as it came off the ‘scope.
Then, a few years later, I worked on the education and public outreach programs for observatories like Swift, Fermi, and others. These would also play a crucial role in detecting and characterizing GRBs (as I mention in the video).
I wound up writing a whole chapter about GRBs in my book Death From the Skies! In fact, I spent more time on that chapter than any of the others, reading a huge number of research journal papers on how a pulse of high-energy X- and gamma rays from a relatively nearby GRB would affect our atmosphere.
This is a field of ongoing work, and it’s fascinating. The papers I read were all over the place, some predicting very bad things from a nearby GRB, others not so bad (all depending on the distance, of course). True story: The papers that concluded we’d be OK I marked with smiley faces on top, and frownies for the ones where we fared not so well. It was the best way for me to delineate the two stacks.
After reading all that research, the one thing I can be sure about: As tantalizing as these objects are to study, I’m really glad they’re really far away.
So you may have heard of all this nontroversy about the Starbucks annual Christmas cup only being a plain red instead of having actual Christmas decorations.* This is all over social media, so I figured I’d help y’all out with this.
So there you go. I fixed it for you.
And if that’s not enough, then perhaps Stephen Colbert can help you figure out what’s what.
It’s nice to see his move to CBS hasn’t changed him. That was perfect.
Tip o' the white plastic lid to Slate's Lisa Larson-Walker for putting this image together for me so quickly and so perfectly.