Bad Astronomy
The entire universe in blog form

Nov. 11 2016 8:45 AM

Trump’s Cabinet: Yeah, It’s Probably Even Worse Than You Imagined

So, it hasn’t taken more than a day for President-elect Donald Trump to turn his sights toward destroying science.

The day after the election, Politico reported on who Trump is looking at to fill his Cabinet spots. The presidential Cabinet consists of people appointed by the president as the heads of the federal executive departments like the Department of Energy, the Department of Education, and so on.

The list is as unsurprising as it is appalling. It’s as if Trump’s transition team made a list of all 300 million Americans, ordered them by competency and ability to not destroy everything they touch, and then skipped right down to the bottom.

Most of the people they are looking at are Trump cronies, who stood by him through the worst of his racism, sexual assault admissions, and white supremacy dog whistling. Newt Gingrich is being considered for secretary of state, Rudy Giuliani for attorney general, and so on. It reads like the roster of villains from an old Hanna-Barbera 1970s superhero cartoon.

But the two spots I want to point out in particular are so galling that—even given the utter depravity of the Trump campaign this past year—my brain almost leapt out of my skull when I saw them.

First, for secretary of the interior, some campaign aides have said that they are looking into Sarah Palin. Yes, that Sarah Palin, one of the most grossly unqualified politicians to ever enter the public eye, who understands nothing about science, and who has open contempt for nature and wildlife. The same Sarah Palin who couldn’t find her way out of a wet paper bag without an oil company drilling an opening for her. Or have you already forgotten about “Drill, baby, drill”?

But don’t worry: Apparently Palin isn’t Trump’s first choice. That belongs to Forrest Lucas, an oil executive, because of course. And don’t worry about Palin, either, as Trump has expressed an interest in having her on his Cabinet somewhere anyway. Unless he finds a spot for J.R. Ewing first.

As for the second spot I want to focus on, I hope you’re sitting down.

Who would make a better secretary of education than … Ben Carson?

Answer: practically every human being on Earth.

Remember Ben Carson? While he may be a retired neurosurgeon (and by all accounts an excellent one), he has some decidedly terrible views on science. Unless maybe I’m wrong, and evolution really is satanic and the Big Bang really is a fairy tale. But I’m pretty sure they aren’t.

Teach the controversy
Welcome to the new national curriculum.

Teach the Controversy T-shirts

So yes, seriously, Trump is considering putting a creationist in charge of this great nation’s education program. The same guy who hypocritically said, “To willfully ignore evidence that you have for some ideological reason is wrong,” and “I just don't have that much faith [in the Big Bang, evolution, and global warming], but [scientists] are welcome to believe whatever they want to believe. I'm welcome to believe what I want to believe."

Sigh. No, you’re not welcome to deny facts, Dr. Carson. Unless, of course, Trump puts you in a position where you have the imprimatur of the presidency to do so.

To be fair, Trump has also said he’ll diminish or cut the Education Department entirely, so yay?

As for everything else, it just gets worse. Trump picked Myron Ebell, a climate change denier, to head up his Environmental Protection Agency transition team. That’s no surprise, as he had already chosen a climate change denying crackpot, Rep. Kevin Cramer, R-N.D., as his energy adviser during the campaign.

Mind you, these are just names being floated around; he may go with different people. But not entirely different; I’m sure the ones he picks will be just as mustache-twirlingly villainous and incompetent for their designated jobs as the names we’ve already heard.

The bigger picture isn’t hard to see here; Trump will be a disaster for the nation, for the climate, and for the world. And he’s still over a month out from taking the reins. This is a nightmare, and one we won’t be able to wake up from for a long time. All we can do now is stay aware, make our voices heard, and hope that nothing he does is irrevocable. There is some hope, but we'll have to work hard to mitigate any damage a Trump presidency will inevitably do.

Nov. 10 2016 9:00 AM

The Colors of Stars: Red vs. Blue

Open clusters—sometimes still called galactic clusters, though that’s an old-fashioned term—are beautiful. They’re clumps of stars ranging from dozens to thousands of members, all occupying a relatively small volume of space. Usually they’re bound together by their own gravity, but over tens or hundreds of millions of years (sometimes even more) interactions between the stars in the cluster fling members away.

Many of the stars have life spans much shorter than this. The most massive ones fuse hydrogen in their cores much faster, making them brighter, hotter, and bluer.

So why, in the Hubble image of the open cluster NGC 299 shown above, are some of the brightest stars red?

It’s because those are massive stars that have stopped fusing hydrogen into helium in their cores. The inert helium has built up in their centers, getting tremendously hot. This extra energy gets dumped into the stars’ outer layers … and when you heat a gas, it expands. So too these stars have swollen up, growing huge. That means their surface area has expanded, and the amount of energy they radiate per square centimeter drops. They cool, and turn red. Astronomers, clever folks that they are, named these kinds of stars red supergiants.

Although cooler than their blue brethren, they are so big that their increased areas more than compensate for the lower temperatures, and they shine tremendously brightly. So even though the blue stars in the cluster are brilliant, the red ones can be just as luminous. It’s also possible these supergiant stars have evolved even further, piling up enough helium in their cores to begin fusing that into carbon. Those can have inert but incredibly hot carbon cores, with thin shells of helium and hydrogen fusing outside of it. The details can be complex, but in the end it all points the same way: The stars are in their end stages, and will soon explode as supernovae.

So look again at that photo. The three bright red stars are probably the most massive stars in the cluster, and were once blue.

This is more than just an interesting piece of scientificness. It’s also a powerful tool: Using sophisticated models based on decades of knowledge learned about stars, we can calculate how old a star will be when it changes from a blue “normal” star to a red giant. This happens to more massive stars first, so by measuring the most massive star that hasn’t yet become a red supergiant, the age of the cluster can be found (assuming all the stars formed at the same time, a reasonable assumption). And indeed, NGC 299 is young, about 15 million to 20 million years old.

How cool (or hot) is that? Although there are lots of details to consider, just by glancing at this image, I can tell you quite a bit about what you’re seeing. Now consider this: NGC 299 is 200,000 light-years away! It’s not even in our own galaxy, but instead in the Small Magellanic Cloud, a satellite galaxy to our own. Lots of much closer clusters look like this through my own telescope, but thanks to the power of Hubble NGC 299 lets slip its secrets to us.

I talk about how stars evolve over their lifetimes in Crash Course Astronomy: Stars, and go over clusters in another episode. Here’s the cluster one for your edification.

And as a final note: These supergiants, in death, seed the galaxy with heavy elements necessary for the creation of more stars, planets, and the basic ingredients for life. In death there is life, which is true on the scale of microbes and humans and the stars themselves.

Nov. 9 2016 3:28 AM

A Dark Day

So. It has come to this. On Friday, Jan. 20, 2017, we will be inaugurating President Trump.

I am sickened by this more than almost anything else I have experienced in life. There is no way around this: Trump tapped into a racist, misogynistic current in this country. Perhaps there is more going on, with effects both subtle and overt that added up to his surge in the end. But the hatred, the othering he mined is there. This is no surprise to people of color, women, or those who have been religiously persecuted. They’ve been warning everyone for years. I heard them, but maybe not enough. Not clearly enough. And like many others I didn't see the extent and depth of that current.

These are dark times, and for the first time in my life I seriously fear for the future of my country. Even when George W. Bush was elected I didn’t feel this as deeply as I do now. Trump is a monster.

And yet, I see some hope. Whereas we had one woman of color in the Senate, we’ll soon have four. Kate Brown was elected governor of Oregon—the first time an LGBTQ governor has ever been elected. And the fierceness of the people I see in my social media means that many will fight whenever this new regime tries to undo the progress that has been made these past few years.

I will be among them. At this moment I’m not sure what it will take. At the very least it will mean listening to those who have been and are likely to be oppressed, and making sure my own voice amplifies theirs. This is something we all need to do, now more than ever.

This will be a colossal struggle. We are facing a sheer cliff of horrid potential disasters to be wrought by the Republican control of the White House, Senate, and House of Representatives, from Supreme Court nominations and regulations on climate change, women's rights, and health care, to economic decisions that can increase the polarization of our nation and further depress the poor. Even freedom of the press is at risk.

Despite all this, here is what, for the moment, I cling to: Tens of millions of people in the United States of America didn’t buy the bill of goods Trump was selling. His election is a tremendous blow, to be sure, but we are still strong. This is our new reality, and what we do next will shape our nation, the planet, and the people on it, for decades to come.

Make sure you do good. We'll need every bit of it we can get.

Nov. 8 2016 8:30 AM

I’m With Saturn

I have a very strong suspicion today will jangle the nerves of a lot of you, my fair readers, no matter whether you are a US citizen or citizen of the planet.

So, to recollect your fraying mind, how about we breathe deep of another planet altogether?

Behold. SATURN.

Nov. 7 2016 8:30 AM

I’m Voting for Hillary Clinton

Well, here we are. Election Day is Tuesday.

I strongly suspect most people have made up their minds already, and so it seems exhorting someone to vote for one candidate over the other may seem superfluous.

Still, let me be clear: I am voting for Hillary Clinton, and will also be voting the straight Democratic ticket in my home state of Colorado. I urge you to do the same in your own home state.

The reasons for this are legion, and I’ll give you some details below. But in the end, Hillary Clinton has devoted her life to making things better for other people, has been a faithful and determined public servant, and a large number of her policies overlap with my own.* She is eminently qualified and will make a fine president. Donald Trump, on the other hand, is a dangerous ideologue whose fringe ideas are un-American and filled with hate. I cannot abide that.

Why state this obvious fact? Because of this not-so-obvious fact: Judging from history, only about half to two-thirds of the eligible population in the U.S. will actually get off their butts and vote. Moreover, young folks—millennials, if you prefer—tend to vote at even lower rates.

I know a lot of people in that age range read my blog and follow me on social media. That is why I am being as clear as I can right now. Millennials overwhelmingly support Clinton over Trump, by 2 to 1. Given how close this election is, even a bump in young voter turnout could make a huge difference. And yes, your voice can and will make a difference. If you don’t believe me, then listen to Hank Green, who confirms this with eloquence and passion.

If you are still undecided, then ask yourself this: Which candidate would you rather vote for?

Trump, who has consistently proved himself to be racist, misogynist, xenophobic, hypocritical, and someone who lies every single time he speaks, and who just put out an ad with a clear anti-Semitic message? Or Clinton, who wants to fight for the rights of everyone, and who carefully considers diversity in her decisions?

If you really are thinking about voting for Trump, think about this: If you vote with him, you are voting with the KKK. This is no hyperbole; he is supported by neo-Nazis, white supremacists, and other white nationalists. Godwin notwithstanding, there are very good reasons to compare Trump to Hitler.

But there’s another vital issue here: Down-ballot voting for seats in Congress and state legislations will be critical Tuesday. As I said, I’m voting straight Democratic this election, something I generally don’t consider. Why? Because the GOP has proved itself to be incapable of governing and of protecting America’s interests.

Its campaign against women’s rights, science, and reality is clear enough. As awful as all that is, there’s more. For example, Republicans have refused to even hear arguments for nominating a Supreme Court judge, an unprecedented and shockingly cynical partisan tactic.

In many states, such as North Carolina and Ohio, they have gone on a spree of voter suppression (making false claims about voter fraud), trying to prevent predominantly black districts (which lean heavily Democratic) from exercising their basic rights as Americans. Trump has publicly stated he wants his followers to “watch” (read: intimidate) people at polling locations. In Ohio, a federal judge handed down an order to prevent that … which was just overturned by the conservative 6th U.S. Circuit Court of Appeals. Read that again: The court gave Trump and his followers the ability to watch people trying to vote. Given how easily his supporters at rallies turn to violence, this is very, very worrisome.

While the House will probably stay Republican (though perhaps weakened), the Senate is actually in play here. If Trump is elected and the Senate remains in the hands of the GOP, the damage it will do is staggering. On the other hand, a Democratic Senate and president will still have to deal with a Republican House, but that’s why we have a system where powers are distributed. This will encourage compromise, something the Republicans have steadfastly refused to do.

I think Joss Whedon (with help from Alan Tudyk and Chris Pine) make this clear in a very funny and razor-sharp video:

The GOP created Trump, and the voting public needs to show Republicans just how badly they screwed this up. Over the years they have become the party of fear, misogyny, bigotry, and hate. Tuesday, we can do something about that.

Vote. No excuses, no baloney, no whining, no protesting by staying home. Staying home isn’t protesting; it’s helping keep things exactly as they are now, or perhaps making them far worse.

Get off your butt and vote.

*And before anyone starts screaming, “Emails!”, just Sunday the FBI reported to Congress that there was no mishandling of classified information. Again. The GOP has spent millions investigating Clinton and has come up with nothing against her.

Nov. 6 2016 9:00 AM

Ashes to Stars, Dust to Dust

2,500 light years from Earth lies truly huge cloud of dense, cold dust and gas: Monoceros R2, which is a staggering 400 light years end to end. That’s four thousand trillion kilometers.

So yeah, that’s a lot of gas and dust. This is the stuff from which stars are made, and a cloud that big can make a lot of stars. Mon R2 is doing just that. On the near side of the cloud, close to the edge, a tight-knit collection of stars is forming. The brightest of these are blasting out fierce light which is dissolving the dust and revealing the stars’ presence to us. This cluster is called NGC 2170, and it was imaged by Ryan Hannahoe using a 36 cm. telescope located in Australia, and processed by astronomer Robert Gendler, to create this stunner:

Nov. 5 2016 9:00 AM

Mars Spins as the Earth Laps It Around the Sun

I’ve been an astronomer all my life, and I love taking my ‘scope out to observe the sky. I have a 20 cm Celestron C8 S-GT, which is small enough to use easily but big enough to catch nice views of planets and deep-sky objects.

Damian Peach has a ‘scope just a little bit bigger, a 35.6 cm Celestron C14. Still, while I dabble with holding my camera up to the eyepiece and taking snapshots, when he takes astrophotographs, what he creates are masterpieces.

That is Mars, imaged by Peach between June 14th and 18th, when it was at its closest to Earth for the year. Earth is closer to the Sun than Mars, and orbits more rapidly. We lap the Red Planet every two years or so, and when we do the two planets are closer together than usual; in late May 2016 they were about 75 million km apart.

Mars appears bigger around that time, so more details are apparent. Mars takes about 24.5 hours to spin once, and Peach mixed and matched different images of Mars over the few days he shot it to create that stunning animation of the planet rotating. You can see broad dark patches, including Syrtis Major on the right at the start of the video. That’s a very flat shield volcano, and the dark color is due to basaltic rock, common from ancient eruptions on Mars.

You can also see the polar ice caps, the southern more prominently. When these images were taken it was just before autumnal equinox on Mars, moving from northern hemisphere summer to winter. The southern pole had been in winter for a half a year or so (seasons last twice as long on Mars due to its longer orbital period), so the ice is more obvious there.

The video ends with the mammoth Olympus Mons volcano hoving into view. It’s the largest known volcano in the entire solar system, roughly 600 km across. If it were centered on Colorado, the entire state would be covered by the base, and it would extend well into the surrounding states as well.

Wanna learn more about Mars? My Crash Course Astronomy video should help:

Peach is amazing at solar system photography. Obviously! But you should go to his website and poke around. Beauty there abounds, as it does in the solar system itself.

Nov. 4 2016 9:00 AM

Able Was I, Ere I Saw Oxo Crater

I know I just wrote about how weird Ceres is (as well as how ridiculously beautiful it is), but honestly, it’s really really weird, and there’s more stuff to show you.

Like Oxo, a 10-kilometer-wide impact crater seen above. Obviously, something peculiar happened there! It looks at first glance to be a more or less normal crater on Ceres, but it’s got that huge slump formation off to one side. What the heck?

There are clues to what happened. If you trace the intact part of the rim around to make a complete circle, you’ll see the collapse must have started outside the crater, with a huge amount of material then sliding into the crater, possibly partially collapsing the crater wall. That shelf feature sticks into the crater like a ledge.

So obviously the object that hit Ceres to make Oxo impacted first, then the land nearby collapsed. Why?

The sharp edge to the slump lies at the top of what looks like a ridge. Straight features on Ceres are associated with cracks or stress in the crust. A ridge can be formed when the crust is stressed, and part of it pops up. If so, that material could have less structural strength after being deformed, so when the crater formed that part of the ridge then slid into the crater. I don’t know if the impact itself did that, or if it happened millions of years later. But I strongly suspect the two events are physically linked.

Note too that the crater has bright material on the left side, most of it looking like it was under the surface, then slid down the wall as it was exposed. Is that more salt, left behind by briny ice, as is supposed to be behind the bright spots seen all over the little world? Note the brighter splotches all around Oxo as well; combined they make it one of the brightest craters seen on Ceres from space.

The floor of the crater is weird, too, like someone shoveled stuff into it. That may be debris from the giant landslide together with debris from what slid down the crater walls over time.

Oxo in context
Oxo crater (upper left) in context, showing more craters on Ceres.


As always when it comes to Ceres morphology (structure and shape), I’m guessing. My point here isn’t to give you a definitive answer to what you’re seeing, actually quite the opposite! We’ve only seen a few of the small worlds in our solar system up close, and Ceres is one of the more unusual ones. We’re still trying to figure all this out.

Ceres is big enough (almost 1,000 km across) that its gravity is strong enough to shape itself into a sphere, but still has very low gravity on the surface, just 3 percent of Earth’s. Unlike moons it was never (as far as we know) near a bigger planet, so it is untouched by the effects of that (such as tides, for example, or interacting with a planet’s magnetic field). It’s not as cold as the outer planets, but cold enough to have water ice. It was trying to be a planet 4.5 billion years ago when it ran out of material to grow, so many planetary scientists think of it as a protoplanet rather than an asteroid (a term used more for the leftover rubble of planetary formation).

Sometimes you have to study the weird objects to understand the bigger picture. Exceptions show you where slightly (or grossly) different circumstances can shape the structure and features of an object. So studying Ceres is a Good Idea.

The Dawn spacecraft, which took the image of Oxo, is mapping Ceres from its current low altitude orbit of just 385 km. It sends back images as well as mineralogical data and elemental abundances. Planetary scientists are building up an understanding of this world, which will in turn build an understanding of many more worlds. Including our own Earth. And since we all live there, studying it and other worlds is a Good Idea, too.

Postscript: If you’re wondering about the odd title, let me ask you: What’s Oxo spelled backwards?

Nov. 3 2016 9:00 AM

What Do Astronomers Mean When They Say an Object “Is in a Constellation”?

It occurs to me that I use a lot of terms that I take for granted but that may mean something else to a reader not as familiar with astronomy or science in general. I thought it might be fun to write some articles defining these terms, so that we’re all on the same page.

Let’s take a look at a very common phrase: What do astronomers mean when they say an object is in a constellation? Like, “Jupiter is in Leo right now.”

Our eyes aren’t terribly good at seeing distances; anything past a few meters away is too far for our binocular vision to work. The nearest object in the sky is the Moon (barring satellites or meteors, both of which are a hundred to hundreds of kilometers above your head), and that’s 380,000 kilometers away! So as far as your eyes are concerned, every object in the sky might as well be infinitely far away.

That means distance doesn’t matter when you look up; everything looks to be the same distance away. It’s as if the sky is the surface of a big sphere and you’re at the center.*

The sky is pretty big, so it would be handy to divide it up into sections, giving each bin a designation or a name. Because it seems like the surface of a sphere, we could parse it out using latitude and longitude, like we do on the Earth. And astronomers do do that, using what we call right ascension and declination, very old terms that divvy up the sky into east/west and north/south coordinates.

That’s fine, and very useful when you’re pointing a telescope. But if we’re just looking up and enjoying the view, Nature has done us a favor. It’s clumped stars together.

Stars aren’t strewn evenly across the sky. In some places they’re closer together, in others not so much. Humans are pattern-seeking beasts, so of course every culture since antiquity has projected their own imaginations onto the sky. So when you see seven bright stars, they’re not just a box with a slash through the middle at a jaunty angle: They’re Orion, the mighty hunter, the three stars of his belt prominent.

Or that twisty S-shaped pattern of stars with two spiked away on the top? That’s obviously a scorpion, and so we have Scorpius (please, not “Scorpio”).

The constellation of Scorpius, annotated to make the shape (more) clear.

Akira Fujii

We call these patterns “constellations”, meaning literally “sets of stars.” For millennia they were only roughly defined, and that could be a problem. The bright star Rigel is obviously part of the pattern making up Orion (it’s his left knee), but if another star is in between two bright patterns, which constellation does it belong to?

To clear this up, in the early 20th century, astronomers made more rigidly defined borders to the constellations, the lines demarcating them along north/south or east/west directions. Eighty-eight such constellations were thus defined. You know many of their names: Sagittarius, Andromeda, Pisces, and so on. Most of them are named after their ancient Greek counterparts, so we have Ophiuchus, the serpent bearer, and Delphinus, the dolphin. Others (mostly in the Southern Hemisphere of the sky) have more modern names, like Microscopium (guess what that’s for), and Antlia, the air pump. Yes, the air pump.

So now, when we say a star is in a certain constellation, it’s like saying a town is in a certain state or country. It’s inside the official borders recognized by astronomers all over the world. Remember, though, in actual, physical space those stars can be incredibly far apart, one a hundred times farther away than another. They just appear close together in the sky because we can't judge their distance by eye.

I talk about this in episode two of Crash Course Astronomy: Naked Eye Observations (around the three minute mark):

In some ways using constellations makes cataloging stars easier. You can designate the brightest one in a given constellation as Alpha, the second Beta, and so on. Most constellations don’t have more than 22 bright stars, so that’s convenient (though in reality it’s more complicated than this). Or you can use numbers for the brightest ones starting with those farthest east in the constellation and moving west (these are called Flamsteed numbers). That’s how we have 51 Peg, and 7 Comae Berenices.

You can also just use coordinates to do this, but that’s awkward, like referring to Denver as “39.7392° N, 104.9903° W.” If you’re trying to point a telescope, that’s fine, but in everyday language it’s a pain. There are dozens of catalogs of stars made over the centuries, so stars are usually referred to using those. Thus HD 209458. Sometimes it’s a mix of name and coordinates, and you get BD+46°3474.

Planets move relative to the stars as they orbit the Sun, so sometimes Venus might be in Libra, and later it might be in Virgo. What that means in reality is that, from our viewpoint on Earth, Venus is superposed on the much more distant stars making up the constellation of Libra or Virgo. Because most constellations are easy to recognize with practice, they make a handy guide to the sky, becoming as familiar as the neighborhood you grew up in, which in turn makes finding celestial objects easier.

I’ll note not every pattern of stars is a constellation. The Big Dipper is a set of seven stars (eight if you include Alcor) that’s part of the bigger Ursa Major constellation. A group of stars like that is called an asterism. Others include the Pleiades (actually a physical cluster of stars) and the Summer Triangle, comprised of the three stars Vega, Deneb, and Altair (in the constellations of Lyra, Cygnus, and Aquila, respectively). You can quibble over semantics like this if you want, but in this case I actually approve of having a definition for constellations, since it’s something that can be defined (unlike “planet”).

So there you go. With the boundaries on the sky defined, every star belongs to one constellation or another, so we say that star is in that constellation. The constellation isn’t a physical thing, but a region of the sky.

Not that folks don’t make mistakes. For example, in Doctor Who, the Doctor says he’s from the planet Gallifrey in the constellation of Kasterborous. That doesn’t really make sense; constellations aren’t physical places in the Universe. Maybe Kasterborous is a constellation as seen from some other planet, but then why would you define your home planet using some other planet’s arbitrary definitions? It’s probably just an error on some writer’s part, which got carried through the series.

If you want to read more, Wikipedia has a good article about this (including constellations from other cultures), and more at my pal James Kaler’s site.

But the best way to learn about constellations? Go outside and look up. There’s nothing like learning by doing.

*You’re not, though, so this is not to be taken literally.

Nov. 2 2016 12:15 PM

Thera Incognita

In my never-ending quest to show you every volcano on the planet as seen from space, I present the gaping wound in the Earth’s crust called Santorini, Greece.

The photograph above was taken by an astronaut on the International Space Station in September. The image is roughly 18 kilometers across or so; the central lagoon is about 12 kilometers in diameter.

What you’re seeing here is the remains of a massive caldera, the bowl-shaped depression left over after the Santorini volcano (also called Thera or Thira) exploded about 3,600 years ago. The explosion was tremendous, apocalyptic: 100 cubic kilometers of ash and rock blew out of the volcano, enough material to make a whole other mountain roughly 4 or 5 kilometers high! The explosive energy of the eruption is difficult to pin down, but from what I can find may have been the equivalent of more than 2,000 megatons —2,000 million tons of TNT. That’s dozens of times larger than the most powerful nuclear weapon ever detonated by humans.

I’ve been to the island of Santorini (the largest of the three islands that were the rim of the caldera), and it’s spectacular. It rises out of the ocean like a wall, and life there is different; it’s a tad hilly, and getting from the port at sea level up to the top is easiest by cable car, if you like terrifying journeys. But it was fun and beautiful, and I found a street vendor that sold peanuts with sesame seeds baked on to them (I think also with some honey to help them stick) and they’re just about my favorite snack on the planet.

Come to think of it, I got some of the same peanuts in Quito, Ecuador, years earlier, which is also on a huge volcano. Coincidence?!

Well, yes. But anyway, standing on the top of Santorini in the town of Oia (the one with the famous blue-domed churches, which are every bit as striking as they appear in photos), it was hard not to have a sense of the cataclysm that befell the region all those millennia ago. As the NASA Earth Observatory page points out, a Minoan-age town has been found, and archaeologists are investigating it. I’m actually shocked by this; I wouldn’t think an explosion of that size would leave anything behind, even buried in ash. But there you go. Physics isn’t beholden to our prejudices.

I’ll be doing some more reading about this event, no doubt. It’s one of the largest volcanic explosions ever recorded in human history, and one of the few I’ve visited. I’m fascinated by the terrible beauty of volcanoes, as much as I am repelled by the devastation they can do. We live in an uneasy truce with the forces of nature, a dynamic equilibrium that can very easily tip one way or the other. I think it’s important to be reminded of that every now and again.