Bad Astronomy
The entire universe in blog form

Sept. 29 2016 9:05 AM

Elon Musk Wants to Put a Million People on Mars

It’s no secret that Elon Musk wants to go to Mars. This week, he showed how he—and a lot more people—just might do it.

At the International Astronautical Congress in Mexico on Tuesday—and after teasing it for many months—he finally revealed his vision for the future of SpaceX, and possibly humanity.* It involves a big rocket, a big spaceship, a big fleet, and big money.

Perhaps you sense a theme here. Bigness.

He calls it the Interplanetary Transport System, or ITS, and he’s not thinking small: He claims this plan can lead to a city on Mars of 1 million people or more, and it could be well on its way in less than a century. It’ll take thousands upon thousands of individual rocket flights.

What he and his company are planning is not in any way easy, and as he himself pointed out with characteristic understatement in a press conference after the announcement, “A lot of things have to go right.”

Yes indeed. So what exactly has to go right to put humanity on the Red Planet?

The Hardware

The plan is to use an enormous rocket, comfortably larger than the Saturn V that sent humans to the Moon, topped with a spaceship that can hold as many as 100 people. It will go to orbit, be refueled using multiple launches, blast its way to Mars, enter the atmosphere using aerodynamic braking to slow, then eventually land on its tail.

SpaceX put together a pretty dramatic animation of the basic flight:

Watching that I felt like I was seeing an updated version of movies I used to watch as a kid. But having thought it over, I have to say that what Musk is planning is doable. Yes, seriously. The engineering challenge is formidable, but technically possible.

There are four critical engineering steps needed to make all this a reality: The rocket must be fully reusable, the spaceship (the section that will actually go to Mars with people and supplies) must be refilled with fuel and oxygen on orbit, the right propellant must be used, and there must be a means of making that propellant on Mars itself.

None of these is easy. Not by a long shot. But they are possible.

comparing ITS to Saturn V
Comparing the ITS to the Saturn V. Yeah, it's big.


First, the rocket. The as-yet unnamed booster is beefy. It’ll be 122 meters tall and about 12 meters wide (the Saturn V was 111 x 10 meters in size). That’s big. But it’s the thrust that shocked me: It’s planned to have a staggering 13,000 tons (29 million pounds) of thrust. The Saturn V—still to this day the most powerful rocket ever launched—had a thrust of 3,500 tons (7.5 million pounds). The SpaceX booster will have a thrust 3.5 times as much as that.

Thrust is one way to characterize how much stuff you can throw into space. This booster will be able to throw a lot. It should lift about 500 tons into Earth orbit, which is a huge payload. The heaviest payload the Space Shuttle took to orbit, the Chandra Observatory, had a mass of about five tons.*

That huge thrust is good, because the Mars spaceship will be huge, too. Measuring about 50 meters long and 19 meters wide, it’ll be so heavy that even the enormous booster won’t be able to put it into orbit by itself. After the booster drops away, the spaceship (again, also as-yet unnamed) will use its own engines to get the rest of the way to orbit, using most of its fuel doing so.

Artwork of the ITS spaceship refueling with a tanker in orbit.


That means the spaceship will have to be refueled. Or, as Musk put it, “refilled”; it’ll need fuel and oxygen used to burn the fuel. That’ll need more rocket launches, which in turn means the booster must be reusable. Like the Falcon 9 first stage, which has now been successfully relanded a half-dozen times; after boosting the spaceship as fast and high as it can, the giant rocket will turn around, slow, descend, and then land itself back at Cape Canaveral in Florida. Musk notes that they’re getting pretty good at this with the Falcon 9, and each landing is more accurate.

The ITS booster could be back on the pad after as little as 20 minutes. It’ll be inspected, and if it’s good to go a tanker full of fuel and oxidizer will be mated to it. The tanker is basically the same design as the spaceship itself (redundant designs save a lot of money and time to develop). It’ll launch into orbit, meet up with the spaceship, mate, and transfer the fuel. This may have to be done several times to give the ship enough fuel to get to Mars.

Once that’s all done, the spaceship leaves Earth orbit, accelerates to interplanetary speed, coasts for a few months, then arrives at Mars. Like the Space Shuttle Orbiters, it will slam into the Mars atmosphere and use drag to slow it down—parachutes for a ship this size are impractical—and then use its engines to land on its tail, just like in those old movies.

entry to Mars
Slowing down using the thin atmosphere of Mars will be a rough ride, but the only way to decelerate enough to land.


But we’re not quite done. To make the spaceship fully reusable (to save on cost per flight), it will need to tank back up and return to Earth (perhaps with people and supplies if needed). To do that, it’ll need to make its own fuel.

This part of the plan is probably the hardest, technologically speaking. The rocket and spaceship will use a new engine SpaceX calls Raptor (the first test model has already been built and underwent a test firing just the other day). It will be more powerful than the Merlins currently used by the Falcon 9, and will use extremely cold liquid methane for fuel. This has some advantages over current fuels; while tricky to design the engine, it does allow for more thrust  and a bigger rocket, but most importantly it can be made on Mars! There’s lots of water there in the form of ice, and carbon dioxide in the atmosphere. Using various methods, these can be processed into methane to make more fuel.

So there you go. Easy peasy, right?

Welllll …

Some Issues

There are some issues with this. For one, we’re not really sure how to make the fuel on Mars, or how much it will cost. The chemistry of it is understood, but in practical terms the ice has to be mined, purified, and processed, and all that has to be done in quantity. That’ll take a lot of machinery, and a whole lot of robust engineering to make sure it works right. Repairs will be difficult until the base becomes sufficient.

Nothing this large has ever been attempted before, either. Despite recent setbacks, SpaceX has been doing pretty well with the Falcon 9, and has learned a lot about bringing boosters back, making reusable vehicles, and the like.

But there’s a helluva long way to go to get to the point where this huge rocket can be built. They need to learn how to do autonomous docking in space (that’ll be tested next year with the Dragon capsule berthing to the space station). They need to relaunch a used booster, and not just once, but multiple times. And of course, SpaceX still hasn’t sent any humans to space.

I’m not saying any of those are show stoppers. Just that this is a long, long road, and SpaceX is just now pulling onto it.

Still, I have some bigger concerns. For example, a trip to Mars using the ITS will take roughly 80 to 140 days (Mars has an elliptical orbit, so sometimes the dance of the planets brings it closer to Earth than other times, so this is an average). This raises the danger of radiation. Normally this isn’t all that big a deal; in interplanetary space, levels are low. But if there’s a solar storm like a flare, this can send deadly waves of subatomic particles racing into space. If such an event occurs, astronauts will have to be protected.

Musk was remarkably cavalier about this, saying it’s not that big a deal. I disagree; it’s something engineers will have to plan for, especially given the sheer number of flights planned. Over 10,000 trips, the odds of a ship getting hit are very high indeed. Water is an excellent shield, and the ships will need plenty of it, so designing the transport to use it that way would be beneficial.

There’s also the issue of recycling air and water, and how that many people will get along for the months of hopefully uneventful travel through interplanetary space.

Also, it’s not clear to me what will happen when the first ships get to Mars. They’ll need protection from dust storms, from radiation, and also just a place to live. I know that this isn’t the kind of thing this presentation was meant to cover in detail, but some mention would’ve been nice to hear. If Musk really wants a million people to live on Mars, those first few will need shelter.

Mars Needs Money

Also, how this enormous undertaking will be financed is a bit hazy. Musk said that SpaceX is funding this right now, spending a few tens of millions of dollars per year on research. The Raptor engines have been funded privately, though recently the Air Force kicked in some dough). Eventually, once the final designs of the Falcon 9 are implemented, the company will spend more resources on it. They still need to get the Falcon Heavy off the ground as well, which hopefully will happen next year.

Raptor test
An actual photo of the recent test firing of the powerful Raptor engine.


The costs of developing and launching the ITS are formidable: It’ll cost more than $500 million just to manufacture a single rocket, spaceship, and tanker. Even if it’s reused many times, this is still a lot of cash, especially when you remember that Musk wants to launch thousands of these things.

SpaceX obviously can’t do it alone, and Musk said he hopes NASA and private companies can pitch in. There is some reason to do so; the engineering will be very useful and easy to spin off, and NASA is very interested in data SpaceX generates. The company is making money on contracts now, and heavy lift vehicles like the Falcon Heavy and the ITS booster could turn a profit for the company.

I strongly suspect that the ITS will cost far less than NASA’s Space Launch System, too, which will cost more than $1 billion per flight (and is not reusable). SLS hasn’t been built or launched yet, so we’ll have to see how it will compare to ITS. Musk hopes to complete the initial development of the first ITS booster in 2020, and send people to Mars in about 10 years or so.

That’s possible. SpaceX has plans to send an uncrewed Dragon capsule to Mars in 2018, though realistically, given inevitable delays, they may have to wait until the 2020 apparition to launch (the same year NASA will send the Mars 2020 rover there, too). Musk wants to send people to Mars by 2024 as well.

But we’re talking a lot of money, at least a $10 billion investment before money starts to be made back. Musk talked about the cost per person to go to Mars as a way to judge the efficacy of this, and more than once talked about people “buying a ticket” for $100,000 to $200,000. It’s possible he might sell some, given that it could be a round trip, but I’m not sure people will pony up that kind of money to go live on Mars until it’s a viable habitat.

So, Will This Work or Not?

So what’s the bottom line? Is this possible?

The answer is yes, it’s certainly possible. But is it doable?

That one I’m not sure about. I think it very well may be, but again fortune will have to smile down a lot on Musk and SpaceX.

Still. Musk has pulled a rabbit out of his space helmet more than once in the past. SpaceX was nearly bankrupt when it finally got a Falcon 1 rocket off the ground, and showed it could go to space. The loss of a vehicle in 2015 slowed but did not stop them, and neither will the more recent Falcon 9 loss. SpaceX has built up quite a bit of momentum, and the Falcon 9 is still operating at a more than 90 percent success rate. And their ability to develop their own engines and bring a booster back from space is very, very impressive (Blue Origin is doing this as well).

While I can’t say for 100 percent sure we’ll be seeing people going to Mars on a rocket with SpaceX’s logo on the side using the ITS … I wouldn’t bet against Musk.

Approaching Mars
How long before 100 people at a time will get a view like this?



And finally, there’s one more question: Why do this? What motivates Musk?

As he said at the announcement:

It would be an incredible adventure. I think it would be the most inspiring thing that I can possibly imagine. And life needs to be more than just solving problems every day. You need to wake up and be excited about the future. And be inspired, and want to live.

I agree. And while some people have quoted him as saying he “wants to die on Mars,” when I talked to him in 2015 about this he waved off this as a bit of headline link bait. Then why go, I asked him.

“Humans need to be a multiplanet species,” he replied.

I agree with that as well. It’ll happen, inevitably, if we choose to make it happen. Musk has made his choice. I hope it pays off. It very well might.

*Correction, Sept. 29, 2016: This post originally misidentified the International Astronautical Congress as the International Aeronautical Conference.

*Update, Sept. 30, 2016: The mass of the observatory was about five tons, but it also had a rocket booster attached that brought the total payload mass to more than 20 tons. Not incidentally, the shuttle Orbiters had masses of roughly 80 tons as well.

Sept. 28 2016 9:00 AM

The First Photo of the Sun

I was doodling about on the internet reading about various astronomical topics—as I do sometimes, and I highly recommend it—and stumbled upon an interesting fact: The first photograph of the Sun was taken on April 2, 1845.

The photo, shown above, was made by French physicists Hippolyte Fizeau and Léon Foucault. They used a daguerreotype, what was really the first kind of photography; a metal plate was treated with chemicals that made it light-sensitive, exposed to a scene, then treated with different chemicals to stop the exposure.

That vintage photo of the Sun shows our star’s relatively sharp edge as well as a handful of sunspots. The spots are pretty big, roughly as wide as Jupiter (for comparison, the Sun is 1.4 million kilometers across).

I was pretty surprised to see the date, though. Why? Because this came five years after the first photograph of the Moon!

The exact date of the first lunar photo is unclear (many attempts were made, with varying results, and apparently some were mislabeled) but chemist John Draper announced he had made the accomplishment on March 23, 1840. At least one photo from around that date still exist, so the claim is probably acceptable.

I would naïvely think the Sun’s portrait would be taken before the Moon’s, since it’s brighter and therefore shorter exposures were necessary. But in fact that may have been the issue; remember, this was more than 170 years ago, and the mechanism to take a very short exposure may have been difficult to create. It’s far easier to take, say, a two or three second exposure than one that’s a fraction of a second if you lack the engineering to make the latter. The solar photograph above had an exposure time of 1/60th of a second.

photo of the Sun
A photo of the Sun I took holding my iPhone up to my solar telescope on Sept. 16, 2015.

Phil Plait

Once the two brightest objects in the sky were captured on photographic plates, though, fainter ones followed. Although I’ve seen different dates listed, it’s generally accepted that on Sept. 30, 1880, astronomer Henry Draper (John’s son) took the first photograph of the iconic Orion Nebula. How far we’ve come—the same photo can be taken easily and in moments using a phone cam held up to a small telescope.

I dabbled in astrophotography when I was in high school (I rolled my own Tri-X film and developed it in my bathroom, for those of you who speak 20th-century photography nerd), and that led to a somewhat meandering path to eventually working on processing images from the Hubble Space Telescope, and calibrating a camera launched into space and placed in the venerable observatory in 1997. Even now I still love it when I can get a decent shot of an astronomical object with my own equipment.

What progress we’ve made since the 1800s! Professional observatories peering deep into the Universe, and “amateur” astronomers create jaw-dropping and scientifically interesting images. It’s thrilling, and it never stops being thrilling.

I tip my lens cap and dew shield to Fizeau, Foucault, Drapers 1 and 2, and all the others who pioneered this field. They may not have realized what they started, and that, nearly two centuries later, their work would still be known, respected, and recognized as one of the most important scientific advances in history.

Sept. 27 2016 10:14 AM

Astrophoto: Dusty Star Birth and Future Spectacular Death in the Swan

Judy Schmidt is a wonder.

She’s an amateur astronomer who loves to play with astronomical images from big observatories, and when she does the results are, well, wondrous.


That is an area of the sky in Cygnus, the constellation of the Swan (also called the Northern Cross), and shows a region called Cyg X, and I hadn’t heard of it before seeing that glorious image. Cya X is a dense molecular cloud very roughly 3,000 - 4,000 light years away. Molecular clouds are vast complexes of cold gas and dust that can form stars. A more famous example is the Orion Molecular Cloud, in which sits the magnificent Orion Nebula.

Sept. 27 2016 9:00 AM

Passing a Kidney Stone Can Be a Real Roller Coaster Ride

Update, Oct. 3, 2016: Well, as I feared (and wrote about at the bottom of this article), the research I cover below is pretty shaky. As my editor Susan Matthews here at Slate wrote, this research is interesting, but at best preliminary, and could use a lot more work to be anywhere near rigorous. It's certainly worth following up on (as I also note), but it's nowhere close to being a "cure" for kidney stones as some outlets wrote. I tried to be as noncomittal as possible when I wrote this article, and I hope I didn't lead anyone astray. Next time, when I cover a new medical story that sounds too good to be true, I'll run it by Susan first!

I am not a doctor. Well, I am, but not the doctor doctor kind. So I don’t usually report on medical stuff (with the exception of vaccines, of course) … but when I read this headline from a press release about a particular research paper, I knew right away I simply had to write about it:

“Researchers Find Certain Roller Coasters May Help Small Kidney Stones Pass”

I know, right? And the story itself is pretty wonderful.*

I’m not sure I can write it better than the press release did:

The foundational study was designed to validate the effectiveness of a 3D printed model kidney used in the research, led by a Michigan State University College of Osteopathic Medicine professor of urology. Dr. David D. Wartinger, currently professor emeritus, initiated the study when a series of patients reported passing kidney stones after riding the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando. In one case, a patient said he passed one kidney stone after each of three consecutive rides on the roller coaster.

OK, first, and again, I’m not a doctor so I’m not really in a position to analyze the accuracy of the research (though see the note at the end of this article). But, let’s assume for the moment that it’s good; the paper makes the usual caveats about preliminary findings supporting the anecdotal evidence.

But that’s what I like straight away about this: A doctor listened to his patients, heard their stories, got curious, and decided to look into the situation. That right off the bat is something I like to hear.

But then it’s how he tested things that slays me. Wartinger and a colleague used 3-D printing to make a silicone model of one of the patient’s kidneys (based on tomographic scans). They then—and get this—filled it with urine and put actual kidney stones of various sizes into it, placing one each in the upper, middle, and lower passageways.

Right? But it gets better:

The researchers, who had permission from the park, kept the kidney model concealed in a backpack during 20 rides on the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando. Researchers then analyzed those 60 ride outcomes to determine how the variables of kidney stone volume, location in the kidney and model position in the front versus rear of the roller coaster impacted kidney stone passage.

It’s OK if you want to read that again. To wit: They got permission from the park, stuffed the kidney model into a backpack, and then, unbeknownst to any other park celebrants, rode with the kidney on a roller coaster.

I hope they bought it some cotton candy first.

I love the idea of medical researchers going on a roller coaster with a fake silicone kidney filled with urine and actual crystals, probably enjoying the ride and screaming at the fun parts, getting off, checking the model, rotating and squeezing the model to reposition the stones … and riding the coaster again.

And then doing it again 18 more times.

And yes, they got some results: 64 percent of the time a stone passed if they sat in the back of the coaster, and about 17 percent of the time one passed if they sat in the front. That result was independent of the size of the stone or where it was in the fake model silicone kidney.

Mind you, from the writeup, this sounds like real science. They observed something, hypothesized an explanation, tested it, and varied their tests to measure the results better. They then conclude their results support the observations, though they don’t say it’s proof. But all in all this doesn’t sound too bad, and if these results pan out, it could prove pretty useful to people who have small to moderate sized stones. At the very least, it does seem to indicate further testing would be useful, including using actual kidneys for the experiment (silicone is not a perfect representative of tissue, after all; and in fact the purpose of this research was to see how well the model behaved in the first place).

So I guess I really only have one question: When they got their results, did they exclaim, “Urea!”?

*NB: The research described was done by an osteopath and will appear in the Journal of the American Osteopathic Association. Osteopathy is a form of alternative medicine, and while some of it uses rigorous medical procedure, there is a lot of quackery involved in the field as well. A whole lot. In the U.S., where this research was done, there appears to be higher scientific standards for osteopathy, though some is still suspect. Caveat lector et emptor. I’ll note that the research described seems legit; the careful mention of preliminary results supporting the anecdotal evidence gives me some degree of relief that this is not too extraordinary a claim. If there’s a doctor or other expert out there who disagrees, please let me know. You can reach me at

UPDATE (Sep. 27, 2016 at 14:30 UTC): Well, nuts. In this post I noted that the research described may not hold water, and I am now hearing word that this may very well be the case. I will update again when I get more information. For now, please keep that in mind while reading.

Sept. 26 2016 9:00 AM

No, NASA Didn’t Change Your Astrological Sign

Seriously? This again?

Over the weekend I started seeing links to articles claiming that NASA has changed the signs of the zodiac. I knew immediately what this was about, even as I was scratching my head about a) how this is news, and 2) how short people’s memories are.

I found a few articles about this NASA “news” here and there; there's one on Yahoo that has the headline, “Your Astrological Sign Just Changed, Thanks to NASA.” The first paragraph alone is burdened with quite a few scientific errors:

We don’t want to be dramatic, but NASA just ruined our lives. For the first time in 3,000 years, they’ve decided to update the astrological signs. This means that the majority of us are about to experience a total identity crisis. Apparently, these changes are due to the fact that the constellations are not in the same position in the sky that they once were, and the star signs are about a month off now, as a result. To further confuse things, there is now a new, 13th sign, called Ophiuchus, which those born between November 29 and December 17 are lucky enough to have to learn to pronounce.

Cripes. No, no, and no. First off, NASA did not “update the astrological signs.” Second, the constellations haven’t changed. And third, Ophiuchus is an ancient constellation, identified by the Greeks thousands of years ago.

So what’s the deal? Well, before we even get started, keep this in mind: Astrology isn’t science; it’s nonsense. It’s been tested 10 ways to Sunday and every time it fails. Even astrologers have come up with tests for it, and it’s failed those. Astrology doesn’t work.

Despite that, lots of people believe in it. That’s why I wrote a lengthy and detailed debunking of astrology.

So what’s the deal with this recent silliness? It has to do with the zodiac. As I wrote in an article on the zodiac:

The planets, including the Earth, orbit the Sun on pretty much the same plane (from the side, the solar system’s planets’ orbits look flat). From the Earth, it looks like the Sun moves around us once per year. The path it takes across the sky is the same year after year, and we call this the ecliptic. The planets all move across the sky in that same path, too.
So, like clockwork, the Sun passes into the same constellations at a certain time every year. You know the names of these constellations: Sagittarius, Libra, Scorpius, Aries, Gemini … the constellation of the zodiac, or, if you prefer, the zodiacal constellations.

These 12 zodiacal constellations have been recognized in one way or another around the world, though most countries (and the International Astronomical Union) have adopted a modified version of them known to the ancient Babylonians and Greeks.

The thing is, there are more than 12 constellations the Sun can pass through. Some are smaller, or have fainter stars, so they get ignored. The biggest is Ophiuchus, the serpent bearer, which is a huge constellation taking up quite a bit of celestial real estate, and in fact the Sun spends more time in Ophiuchus than Scorpius! Scorpius has brighter stars, and an obvious scorpionlike shape, so it gets better press.

So no, NASA didn’t add in Ophiuchus, or change the zodiac, or anything like that. It’s been around this whole time, but it’s been ignored by astrologers. They’re the ones who should take the blame for all this, not actual, real scientists who don’t even think astrology is worth wrapping fish in anyway.

Worse, there aren’t really 13 zodiacal constellations. By some counts, there are as many as 21! Not only that, but the Earth wobbles like a top, very slowly, and over centuries and that changes the dates the Sun is in a given constellation. If you were born in late March in ancient Greece, you would’ve been an Aries. Today, you’d be a Pisces.

Given that astrology is based on all this, shouldn’t they at least get their basic facts straight before trying to influence your life?

Finally, why is this suddenly news? This is the final irony here. This new foofaraw got started, apparently, due to an article on a NASA site for kids called SpacePlace. I like this site a lot and refer quite a few parents and teachers to it. It has simple explanations written at a level for children to understand, and it’s fun and accurate.

The SpacePlace article, Constellations and the Calendar, has been around a while but was recently updated in January 2016, which may have caught some astrology believer’s eye. The article—well worth your time to read—talks about how the zodiac constellations are defined, and how, over time, they’ve changed (as I described above). Apparently, someone didn’t read it very carefully, or didn’t understand it, and wrote that NASA had changed the zodiac. So, yeah. Wow.

But this isn’t even the first time this sort of thing has happened: Almost exactly the same story bubbled up in 2011!

You can’t keep a good piece of pseudoscience down. It’s like a zombie, always rising again.

You know what also rises? The Sun. And when it does, it’ll be because the Earth is spinning, and orbiting around it, and we’ll see the stars and planets and moons doing their thing. And we’ll study them with science and learn their ways, and if people who believe in astrology want to keep looking to the past, well, let ‘em. As long as they promise to remember it.

And that reminds me: In one sense, astrology is correct. There is a group of people whose lives are affected by the stars and planets: astronomers. And if I can help spread that particular love, then I’ll be more than happy to.

P.S. Another article about this, written by astrologers in September 2016, once again tries to blame NASA for all this. As icing on the cake, they end the article with this gem: “Here’s a deal, NASA: We won’t meddle with the next space shuttle mission if you stop giving the world another astrological identity crisis.”  Just a note: The Space Shuttle program ended in 2011.

Sept. 24 2016 9:00 AM

Infinity Squared: An Astonishing Video of the Night Sky

Ben Canales is an amazing astrophotographer, specializing in time-lapse animations of the night sky (see, for example, this, this, and this).

He recently got his hands on a Canon MH20f-SH: A ridiculously sensitive camera capable of a stunning 4 million ISO! Even at 400,000 ISO it’s able to capture light so faint that it can be used to take passably well-lit video even at night … including the very dark night skies of an Oregon Star Party taken during the 2016 Perseid meteor shower.

Canales followed a score of high school students who went to the star party to experience the sky for themselves, and what he produced out of that night is, simply put, magical. Watch to the very end, and please, listen to what those students are saying.

I’d be hard-pressed to pick what my favorite part of this video is, but this comes close:

… you feel so small, but at the same time you know that there’s so much out there. [struggling for words] It’s… it’s… it’s kinda like unexplainable unless you’re out here yourself, [and] people should come out here and see this for themselves, it’s absolutely incredible.

Oh, I couldn’t agree more. I can wax poetical about the profound beauty of the night sky for a long time, but it’s a pale shadow of what it is to go out there be out there.

I know that 2016 has not been the best year for so many of us, but if you need a bit of joy and awe and the sense that there truly are greater things—and if you are physically capable of it—I urge you to find a dark spot and contemplate the cosmos. You’ll be better for it.

Sept. 23 2016 9:00 AM

Shaking Hands With Pele

Our world is extraordinary.

Of all the planets, ours alone has a surface driven by tectonics*. Under the relatively thin crust lies a layer of incredibly hot rock under unimaginable pressures. The physics of this material is so bizarre and so extreme that solid rock can behave in some ways like a liquid, with hot material rising and cooler stuff sinking… though it only creeps along at something like two centimeters per year.

But move it does, driven by the heat of the Earth’s core below it, powered itself by four sources: radioactive decay, leftover heat from the planet’s formation billions of years ago, heavier material sinking down to the core, and the squeeze of gravity on all of this. As the hot material of the mantle slowly convects upward, it can punch through the thin solid crust of our planet, forming volcanoes.

I’ve visited many volcanoes in my years, including the monstrous Kilauea on the Big Island of Hawaii. Twice before I’ve stood near the rim of the crater Halema’u’ma’u, watching the plume of sulfur dioxide blowing up from a lava pool down deep in the throat of the vent. But I’ve never seen the lava itself… until just the other day.

Lava erupts in 15-meter-high fountains in the crater of Halema'u'ma'u, a crater in the Kilauea volcano.

Phil Plait

That photo shows the view from the Jagger Museum, located roughly two kilometers from the vent (you can see a live web cam on the Hawaii Volcano Observatory page). I used binoculars to magnify the shot, and you can see the glowing lava clearly. Usually the surface of the lava lake is too far down the vent to see, but for the past few days pressure from below has driven it up to just below the rim. It’s a little hard to tell, but the yellow layer of rock is the rim, stained by sulfur fumes. The lava lake is about 15 meters below it, and the lava you can see in the shot was fountaining up as high as the rim itself.

I stood in awe watching this. That’s liquid rock, far denser than water, hundreds and thousands of tons of it launched into the air as gases from below drove it skyward. The forces below our feet are immense.

The volcano is littered with ancient lava flows, active steam vents (water from rain seeps down into the rock, gets heated by the magma below, and blasts back up as steam; standing in it feels like the Earth itself is exhaling on you), and in some cases dead pit craters, like Devil’s Throat:

Devil's Throat
Aptly named, I'd say.

Phil Plait

This probably started as a cavern, but the walls collapsed, widening it and creating sheer vertical cliffs. It’s about 50 meters across and the same deep. It’s not a perfect circle, but the curve to the wall is obvious, as is the layering. That’s not sedimentary layering like you’d see in the American southwest; no such thing has happened on the Big Island. In this case, the layering is from dozens, hundreds of volcanic eruptions, each sending lava coursing away from the volcano. Everywhere you go on Hawaii you can see this same sort of thing.

It’s a stark reminder that the entire island is a gigantic volcano. Five of them, actually (Kilauea, Mauna Loa, Mauna Kea, Kohala, and Hualālai). Lava flows crisscross each other, some dark —these are generally fresher, only decades old— and some brown or redder, oxidized as they age, getting quite literally rusty.

Hawaii is known for its lush climate and biology, of course. Some of the plant and animal life is natural, coming to the island by wind, water, or wings, and some brought by humans for good or ill. But when you see the vast fields of sharp aa or rolling pahoehoe lava, it’s even more incredible to think anything can get a toehold here. But, as some people like to say, life finds a way.

I’ve been in Hawaii over this past week with friends and family, and as we've traveled along together our tour guides regaled us with colorful stories of native Hawaiian legends, most of which are richly layered “just so” stories to explain the volcano, the life on it, and other aspects of the islands. I’ve really enjoyed hearing all these tales, which —though perhaps more metaphorical than the scientific explanations—are wonderful and poetic. Pele, the goddess of the volcano, features prominently in them, capricious and powerful. Seeing the lava fountain and the force of the lava for myself, I can understand why the stories describe her so.

I work from home most times, and it’s easy to get overly focused on the day to day work, buried in the things that must be done, and to forget what an astonishing and amazing and awe-inspiring place we live on.

It’s worth remembering that, though. You need not travel far to experience it; the entire planet has something to offer if you simply look at it the right way. I hope that in whatever way you can, you take the time to do it.

* If you want to call Pluto a planet, then a case can be made for at least some of its surface responding to such forces as well, though under somewhat different circumstances.

Sept. 22 2016 9:00 AM

An Exploding Volcano Slowed Global Warming. Briefly.

As our planet warms up, the sea level is rising. This seems obvious; ice is melting from Antarctica and Greenland at a rate of several hundred billion tons per year, dumping all that water into the ocean. Less obvious is the fact that as water warms, it expands. Warmer water takes up more volume than cooler water, so as the oceans absorb the majority of heating of the planet, they expand, and that actually is a bigger effect on sea level rise than ice melting.

But another effect is that as the Earth warms, the rate at which ice melts and the oceans expand will increase, too. That means that if you look in the past, you’d expect sea level to be rising at a certain rate, but if you look at it more recently, that rate will be larger. If it rose at, say, 2 millimeters/year some time ago, it may be rising at 3 millimeters/year now.

That’s important. If you’re looking at the effects of sea level rise on coastal development and population over the next century, the difference in rates means your prediction could be off by several centimeters if you’re not doing the math correctly. That’s a huge difference, like the difference between flooding only during a storm surge and constant flooding.

For decades, scientists used tidal gauges (usually near coastlines) to measure sea level. In 1992, the TOPEX/Poseidon satellite was launched, using sophisticated techniques to measure it far more accurately. Scientists expected the satellite to easily detect the sea level rise acceleration after just a few years of observation.

To everyone’s surprise, though, they didn’t. The rate at which the global sea level was rising was steadier than expected. Were the global warming predictions off?

New research has finally solved this mystery: The predictions were fine. The problem was Pinatubo, and bad timing.

In 1991, Mount Pinatubo in the Philippines erupted. More like exploded: It was the second largest volcanic event of the 20th century, blasting hundreds of millions of tons of ash, gas, and aerosols (particles suspended in air) into the atmosphere. This had the effect of cooling our planet a bit; the particles reflected incoming sunlight, reducing global warming.

It’s not a huge effect, but it was enough that it changed our climate. Cooler land meant less ice melting, and cooler oceans meant the thermal expansion was abated somewhat. That in turn meant sea levels actually went down, by as much as six or seven millimeters!

That sounds like good news, but it was temporary. Within a few years our warming planet took hold again, and sea levels began to rise once more as the waters heated up and ice melting returned to previous rates.

But it happened just before TOPEX/Poseidon launched. So when the satellite started taking measurements, it saw a faster than usual sea level rise as the Earth recovered from the volcanic event; the normal acceleration due to global warming plus the recovery of the sea levels after the eruption. Weirdly, that masked the effects of global warming a little bit, throwing off estimates.

Because the levels were going up faster than usual, it looks like the rate of sea level rise has dropped in the past decade. In the 10 years after TOPEX/Poseidon launched, it saw sea level rise at 3.5 millimeters/year ever year, but then, over the subsequent decade, the rate dropped to 2.7 millimeters/year every year.

In a sense this is good news. Well, not as bad news: Global warming is increasing sea levels by a lower rate than once thought.

But this is still pretty bad news, because we don’t want global warming to be causing sea level rise at all. But it is.

While volcanic eruptions are devastating locally, they do help with global warming a bit. But the effects don’t last long, and in the medium to long run are completely overrun by human activities which contribute to warming. The most cataclysmic eruptions only put a fraction of the junk into the air as humans do (to the tune of 40 billion tons per year of just carbon dioxide).

While we can’t trigger volcanoes to explode when we want, there are other ways to mitigate global warming. The overwhelming cause is burning fossil fuels, and we have within our reach the ability to dramatically decrease our use of such old technology. We can make the switch to renewable energy production like solar and wind, and do so in a way that actually helps our economy, despite the claims of doom from those who say it would hurt us (after all, as the price for solar energy continues to drop, shouldn’t we let the market decide?). We can actually save the world, and ourselves, and getting on to the road to a solution isn’t even really all that difficult.

As I have said many times, and will continue to say as long as I need to: The first step is to vote global warming deniers out of office. Only then will we be able to tackle this issue seriously and give it the attention it—and we—desperately deserve.

Sept. 21 2016 9:00 AM

Rosetta’s Final Resting Place Has Been Chosen

In August 2014, the space mission Rosetta rendezvoused with the four-kilometer-long comet 67P/Churyumov-Gerasimenko, and made history. It was the first spacecraft ever to orbit a comet, and the first to send a probe to the surface. It has returned thousands of images of the double-lobed comet to Earth, and given scientists enough data to spend a lifetime examining.

But it’s also time for the mission to come to an end.

Over the past few weeks the orbiter’s trajectory has been changed, bringing it down ever closer to the surface. On Sept. 29, when it’s just a few kilometers away, the orbiter will execute a “collision maneuver,” sending it down to the surface. On Sept. 30 it’ll make contact, and be switched off. The mission will be over.

It will take data all the way down, observing its strange partner for the past two years. And now the European Space Agency has released information about its final resting place: an area on the smaller lobe of the comet near the 130-meter-wide pit called Deir el-Medina, named after a city in Egypt that also has a wide pit nearby. On the comet, this is an active pit where ice sublimates (turns directly into a gas) when it’s heated by sunlight. Dust blows out along with water vapor, creating the fuzzy head and long tail of the comet when it nears the Sun.

Deir el-Medina seen by Rosetta from a different angle, in September 2014, not long after first approaching the comet.


Rosetta should touch down pretty close to the pit. Hopefully it will see inside the pit, down into the layers eroded away by countless passes around the Sun. There are also blobby structures nearby that may be “cometesimals,” small snowballs from the early solar system that came together to form the comet. If they are, they’re among the oldest formations we’ve ever seen, close to 4.6 billion years old. Seeing them is like seeing a time capsule to when the planets were still forming.

Funny: An operations manager in the press release commented that the orbit of the probe is being affected by the comet’s gravity, changing the shape in ways difficult to predict. If the comet were a perfect sphere, its gravity would be easy to navigate. But the comet is shaped more like a squat, off-kilter bowling pin (oh, who am I kidding; it looks like a rubber duckie). Sometimes the small lobe is near the probe, sometimes the bigger one. That enough is sufficient to mess with Rosetta’s path, but the comet is also not homogeneous; it’s lumpy, and that means the strength of its gravity changes even more depending on the probe’s position.

So they’re being careful, edging the spacecraft ever-closer to the comet. I imagine the images we’ll be getting will be as amazing as anything we’ve seen so far—and so far they’ve been truly amazing—and only get better as the distance closes.

And on Sept. 30 … well, we’ll see. It’s been an amazing journey, but there’s still a little ways yet to go.

Sept. 20 2016 9:00 AM

March … I Mean April … I Mean May … I Mean June … I Mean July... I Mean August 2016 Is the Sixth … I Mean Seventh … I Mean Eighth … I Mean Ninth … I Mean 10th … I Mean 11th Temperature Record-Breaking Month in a Row

N.B. If this article sounds familiar, it should. This has been happening so frequently I just copied the post for March April May June July and updated it.

October. November. December. January. February. March. April. May. June. July. And now August.

For the sixth seventh eighth ninth 10th 11th month in a row, we’ve had a month that has broken the global high temperature record.

According to NASA’s Goddard Institute for Space Studies, March April May June July August 2016 was the hottest March April May June July August on record, going back 136 years. It was a staggering 1.28°C 1.11°C 0.93°C 0.79°C 0.84° 0.98° C above average across the planet.* The previous March April May June July August record, from 2010 2014 2015 2011 2014, was 0.92° 0.87° 0.86° 0.78° 0.74° 0.82° above average; the new record beats it by well over a tenth of a degree.

Welcome to the new normal, and our new world.

Note: NASA has created a short video describing its efforts to measure global warming, specifically pointing out that the first six months of 2016 have all been the hottest months on record of their kind:

As you can see from the map above, much of this incredible heat spike is located in the extreme northern latitudes. That is not good; it’s this region that’s most fragile to heating. Temperatures soaring to 7° or more above normal means more ice melting, a longer melting season, loss of thinner ice, loss of longer-term ice, and most alarmingly the dumping of billions of tons of fresh water into the saltier ocean which can and will disrupt the Earth’s ability to move that heat around.

What’s going on? El Niño might be the obvious culprit, but even earlier in the year when it was strong it was only contributing a small amount of overall warming to the globe, probably around 0.1° C or so. That’s not nearly enough to account for this. Also now, even though the Pacific waters have returned to more neutral conditions, we're still experiencing record heat.

Most likely there is a confluence of events going on to produce this huge spike in temperature—latent heat in the Pacific waters, wind patterns distributing it, and more.

JMA August temperatures
The Japanese Meteorological Agency measured similar temperatures as GISS (though it uses a different baseline for the average). Note the trend. See a "pause"? I don't.

Japanese Meteorological Society

And underlying it all, stoking the fire, is us. Humans. Climate scientists—experts who have devoted their lives to studying and understanding how this all works—agree to an extraordinary degree that humans are responsible for the heating of our planet.

That’s why we’re seeing so many records lately; El Niño might produce a spike, but that spike is sitting on top of an upward trend, the physical manifestation of human induced global warming, driven mostly by our dumping 40 billion tons of carbon dioxide into the air every year.

Until our politicians recognize that this is a threat, and a very serious one, things are unlikely to change much. And the way I see it, the only way to get our politicians to recognize that is to change the politicians we have in office.

That’s a new world we need, and one I sincerely hope we make happen.

*GISS uses the temperatures from 1951–1980 to calculate the average. The Japanese Meteorological Agency uses 1981–2010, which gives different anomaly numbers, but the trend remains the same. Realistically, the range GISS uses is better; by 1981 global warming was already causing average temperatures to rise.