On March 8, Earth lapped Jupiter in their race around the Sun. Earth orbits closer to the Sun than Jupiter, and so moves much more rapidly. Like a car on the inside track passing one on the outside, this meant that Earth was as close to Jupiter as it would be all year.
Astronomers call this event opposition, because it means the outside planet is opposite the Sun in the sky as seen from the inside planet. So, to us on Earth, Jupiter rose when the Sun set, was up all night, and appeared as big through a telescope as it would until the next opposition (which will be on April 1, 2017).
During the March opposition, planetary photographer extraordinaire Damian Peach aimed his 35 cm telescope skyward and shot video of the huge planet. Using software to pick and choose which frames minimized the blur of the atmosphere, he assembled the amazing image of Jupiter shown above. It “unwraps” Jupiter, mapping the spherical surface onto a rectangle. This distorts some of the features near the poles (like when a similar map of Earth makes Antarctica stretch all the way across the bottom, or magnifies how big Greenland is) but still gives a great overview of what’s what.
The most obvious feature is, of course, the Great Red Spot, a persistent storm that is at least four centuries old, and possibly far older. For reasons unknown, the Spot has been shrinking of late, but it’s still big enough to swallow the entire Earth without our planet touching the sides.
My favorite part of this image is the turbulence downstream of the Spot, as the circulating atmosphere flows around it. It’s much more apparent in the big version of this image, and I encourage you to take a look.
You can also see the banding of Jupiter, circulating weather systems that stretch all the way around the planet (you can find out all about this and more in my Crash Course Astronomy episode about Jupiter). Smaller pale circular storms dot the midlatitude southern hemisphere, and it’s easy to spot similar features all over the planet.
Using all the best frames from the observations over March 18 through 22, Peach created this stunning video of the monster planet rotating.
Jupiter spins once every 10 hours, so Peach had to match each image taken over five days carefully to get them to fit into the animation. It really gives an impression of the immensity of the planet; remember, 11 Earths would fit across Jupiter’s face!
Jupiter is always one of my favorite targets when I take my own telescope out. It’s big, easy to see (it’s the fourth brightest natural object in the sky, after the Sun, the Moon, and Venus), and the motions of its four biggest moons are easy to spot night after night, and sometimes in just a few hours.
Unfortunately it’s not well situated to observe now; it rises around 3:30 in the morning and sets in the afternoon. But starting in 2017 it’ll be gracing our early evening skies again, and I hope for a chance to take some time getting reacquainted with it. If you have an opportunity to see it—and many astronomy clubs have public star parties—I urge you to take it. Your view may not be as a good as Peach’s, but it hardly matters. Seeing a planet like Jupiter with your own eyes is an experience you won’t soon forget.
I’ll be the first to admit there’s a dearth of things to be thankful about this particular fourth Thursday of November. If you’ve been paying attention at all, the evidence is pretty strong. I need not go into details.
Unlike a serving of yams, I won’t sugarcoat it. This isn’t a feel-good, hey-everything-will-be-fine post. I’m very, very worried about the future, well beyond the next four years.
But I’ll tell you what. I’m thankful for and to the people who speak up, who are vocal, who have everything to lose and still put it all on the line. America is based on people telling others to stuff it when they become oppressed, and while our society has been and remains imperfect in many ways, this is still one of its greatest strengths.
If you need something to hold on to, find what it is and grab it with as much fervor as you can muster. But save some for the road ahead, because you’ll need it.
For me, that anchor is manifold. It includes true patriots who fight for what America means. It includes my friends and family. It includes the Universe itself, which I honestly do turn to in times of stress to remember that there is majesty and beauty and vast scale against which to put my own life in perspective.
And my goats. They help too.
Whatever it is for you, hold on. We all need you, very much. And we will continue to need you, even after we get out of this current mess. America is never finished; there’s always more to do, and we need everyone we can to help it along.
Trump’s Plan to Eliminate NASA Climate Research Is Ill-Informed and Dangerous
In a month where it’s easy to get outrage fatigue at the incoming Donald Trump administration, he still finds a way to be brazenly awful and make terrible, dangerous decisions:
In an interview with the Guardian, Bob Walker, a senior Trump adviser, said that Trump will eliminate NASA’s Earth science research. This is the mission directorate of NASA that, among other important issues, studies climate change.
In other words, Trump and his team want to stop NASA from studying climate change. From the article:
Nasa’s Earth science division is set to be stripped of funding in favor of exploration of deep space, with the president-elect having set a goal during the campaign to explore the entire solar system by the end of the century.
The motivation behind this is clear: Utter and complete denial of science. I’ve written many times that Trump denies climate change is even real, saying it’s a Chinese hoax. He’s said there’s no drought in California, even while the majority of the state is under intense drought conditions. He picked a climate change denier to advise him on energy policy during his campaign, and picked an even more egregious denier to head up the EPA transition effort. In a recent statement he appears to have softened that hard-line stance, but given the torrent of lies dropping from Trump’s mouth, his history of science denial, and Walker’s current statements, I see no reason to believe Trump’s attitude has changed.
Actions speak louder than words, and his actions are clear.
If this slashing of NASA Earth science comes to pass, it will be a disaster for humanity. This is no exaggeration: NASA is the leading agency in studying the effects of global warming on the planet, in measuring the changes in our atmosphere, our oceans, the weather, and yes, the climate as temperatures increase. They have a fleet of spacecraft observing the Earth, and plans for more to better understand our environment. That’s all on the chopping block now.
Especially irritating are the details of what Walker said. Calling climate change research “politicized science” is so ironic you could build a battle fleet out of it, because it was the GOP who politicized it. They are the ones who attacked it as a party plank, they are the ones who have been taking millions in fossil fuel money to fund an organized disinformation campaign about it, they are the ones who harass climate scientists.
The specific example that crystallizes all this? Republicans love to claim that progressives started using the phrase “climate change” instead of “global warming” because the Earth wasn’t warming. This is 100 percent pure bull crap. First, the Earth is warming; the “pause” isn’t real. Second—and this is the real kicker—it was Frank Luntz, a Republican strategist, who convinced Republicans to switch phrases because the term “climate change” is less frightening, and therefore easier to downplay.
This is the modern GOP. Scream and wail about what “the left” is doing, when in reality it’s the GOP who are to blame. It’s all very calculated, and downright Orwellian. The hypocrisy is palpable.
Walker also said, “Earth-centric science is better placed at other agencies where it is their prime mission” is particularly galling. The best agency for that would be the National Oceanic and Atmospheric Administration, which for the past two years has been under relentless attack by the GOP in the form of Lamar Smith, R-Texas, chairman of the House Committee on Science, Space, and Technology. He has done everything he can to tie NOAA in knots and prevent them from studying global warming, including subpoenaing ridiculous amounts of information and intimidating its administrator, the astronaut and national hero Kathryn Sullivan.
Lamar Smith is the modern day Joseph McCarthy. But we’re still waiting for his at long last sense of decency.
So Walker saying Earth science is better done at NOAA is a lot of malarkey. Worse, NOAA relies heavily on NASA for mission support, including launching satellites. How will that be affected under a Trump presidency?
There’s one other exasperating thing Walker said, and it’s a pants-on-fire doozy:
Walker, however, claimed that doubt over the role of human activity in climate change “is a view shared by half the climatologists in the world. We need good science to tell us what the reality is and science could do that if politicians didn’t interfere with it.”
That is complete garbage. “Half the climatologists”? In reality, at least 97 percent of climatologists agree that humans cause global warming, and the data show you can’t explain the current rising temperatures without human influence.
The final wail from the ghost of Orwell is that last sentence by Walker. He’s a politician, and he’s interfering with science.
And need I remind you, this is all happening while the planet has seen a string of record breaking heat, month after month, where the Arctic sea ice is melting in unprecedented ways, where President Obama has said climate change and its denial is a threat to national security, and a top military advisory board has said the same thing.
I find it outrageous that Trump won this presidency in large part by stoking fear in people, yet he denies the single biggest thing we actually should be scared of.
Is there any good news in this? Perhaps. Just because Walker says this will happen doesn’t mean it will, though that is thin gruel to get sustenance from. Some people are fighting back; for example the NOAA has told Smith they won’t acquiesce to his awful demands, and climate scientists like Michael Mann, Gavin Schmidt, and Katharine Hayhoe are speaking out.
Hopefully the public will as well. Contact your representative and senators. Tell them that the Earth is a planet, and studying it, studying its climate and our effect on it, is absolutely part of NASA’s mission, and perhaps its most critical one.
Mars Is Going Through a Bit of a Dry Spell. How Do We Know? Rusty Meteorites.
I love meteorites. I have quite a few myself; while I’ve never found one on a hunt I’ve bought them from collectors. There’s a wealth of science in them; many are as old or even older than Earth, having formed in the early solar system. Others are from asteroids that got smacked by other asteroids, the impact sending out shrapnel that eventually impacted Earth.
Of course, other planets get hit by them too. We’ve seen asteroid (or comet) impacts on Jupiter… but we’ve also seen meteorites on Mars. In 2005 the rover Opportunity found a meteorite on Mars, the first time we’d ever seen one on another planet’s surface. Many more have been found since then.
It turns out that finding meteorites tells us more than just about them: They can be used to measure the environment in which they sit, too. A team of scientists used some Martian meteorites to do just that, and discovered something rather interesting: Mars has been very, very dry for the past several million years.
Now, we know Mars is dry. But there’s some evidence for moisture; for example, the Curiosity rover found daily and seasonal moisture exchange between the surface and the atmosphere.
Lots of meteorites contain iron. Some are mostly iron, like a peculiar looking one found by Curiosity just recently. Others are mostly rock (called stony meteorites), but even they are rich in iron. While out in space that iron is pristine, but once it lands on a planet like Mars, weathering can begin, including oxidation. Under water, for example, the iron in meteorites will rust. That can also happen if there’s moisture in the air, too.
Combining all this, the scientists looked at several meteorites found by rovers on Mars, including the chemical analysis done by the rovers (Opportunity has a spectrometer, an instrument that can determine the chemical composition of specimens). They examined the data and found that the meteorites contained oxidized iron — most likely due to Martian weathering.
They also were able to make various assumptions about the ages of the meteorites; for example some are near a crater that has been dated at 50 million years old. That’s an upper limit to their age; they could have been from that impactor, or they may have fallen later. Others were dated using similar methods.
What the scientists found is that the rate of oxidation is at best the same as what it would be at some of the driest places on Earth (like Antarctica), and could be far slower than that, perhaps as much as ten thousands times slower.
What this means is that in recent times, at least at these locations, Mars is dry, dry, dry. Perhaps at other spots the conditions are wetter, but the resting places for the meteorites are positively desiccated. As it happens, Mars may be in an interglacial period, an epoch of time when it’s a tad warmer than usual, with drier conditions at the equator. These meteorites support that idea.
In some sense that’s good news; it means that interpreting the geology at these places is easier, since weathering is low. But it also means that finding extant life on Mars may be harder. Looking at higher latitudes where we know there's ice under the surface is still worth trying, though.
I love all this. One aspect of doing scientific investigation is looking around you (or whatever you’re using to look around) and seeing what there is to see, inventorying it, and then figuring out what you can do with the tools at hand. And in so many cases, nature provides! It’s funny to think that rocks from space can hit a bigger rock from space, and from that we can make all sorts of measurements, even from tens of millions of kilometers away.
But this is why we explore space, why we send rovers and landers and orbiters and flybyers to other worlds. Sometimes we don’t know what we’ll measure until we get there, and we won’t even know how we will measure them until we get there. But once we’re there, entire worlds are open for us to investigate.
No, There’s No “Huge Blue Globe” in Front of the Sun (Sigh)
For reasons that elude me now, I decided to check on Facebook on Sunday night before going to bed. On the right sidebar, I noticed that it said that “NASA” was trending. That surprised me; had I missed some important event or amazing new Hubble image being released?
I clicked on the link, saw the news item, and let out a long sigh. This is what I saw:
Yup. Another “Space telescope takes a picture we don’t understand and therefore it must be a UFO/Nibiru/NASA coverup/End times/cats-and-dogs-living together situation.” In this case it’s a huge blue globe appearing “in front of the Sun.” Except, of course, it’s nothing of the sort.
Pardon my snark, but this ain’t my first rodeo here. I’ve had to debunk stuff exactly like this dozens of times, and it’s almost always the same story.
On the Facebook trends page there were links to a few articles, the first being to that epitome of accuracy, the U.K. tabloid Daily Mail (for context, I heard the Mail got a science story right once, but I’ve never been able to verify that). The article quotes people making a lot of breathless claims, like the Sun “reacted” to the sphere, or that it might be a “rouge [sic] planet.” A photo caption claims it’s a huge blue sphere and it’s “mystifying scientists.”
Sure. Except no.
I’ll explain in a sec, but first things first: How did this all start? Apparently, a woman named Pamela Johnson posted about this on Facebook, which got the ball rolling. It’s an image from NASA’s STEREO A spacecraft, one of a pair of probes orbiting the Sun. They were launched in opposite directions, designed to take images of the Sun from different angles, and provide a more global view of our tempestuous star. STEREO B has been having some issues lately due to hardware problems, but STEREO A is still ticking along, on the other side of the Sun from the Earth.
The image is weird, certainly. Johnson makes some, um, unorthodox claims about it involving New Age things that I won’t delve into.
Being more of a sciencey persuasion, I looked at the image carefully to try to figure out what I was seeing. I went to the STEREO image search page and found images from that date. Quite a few show the anomaly, while others don’t. At the top of this article is a cleaner shot of one of the images, taken on Thursday at 17:29 UTC.
The two bright spots with vertical lines going through them I recognized as planets right away; planets are bright and overload the detectors a bit, bleeding light into neighboring pixels (this is called blooming and happens all the time in digital detectors, including spacecraft that observe the Sun; UFO hunters and Planet X conspiracy theorists tend to go bananas over such things). Incidentally, the planet to the lower right is Venus, and the one closer to center is … Earth! Because STEREO is on the other side of the Sun, the Earth is in its field of view. So that’s us! Cool.
As for the giant blue ball, that’s no mystery: It’s the Sun. I mean, clearly that’s what it is. The real question is why it appears to be superposed on the image of the planets.
Briefly, the image comes from an instrument on STEREO called the Sun Earth Connection Coronal and Heliospheric Investigation, or SECCHI. This has several detectors on it, including the Heliospheric Imager, or HI, which is a visible-light camera designed to look at the Sun’s corona, its faint atmosphere that streams into space. [Update: To be clear, it doesn't point directly at the Sun, but instead off to the side to better see the corona.] The image showing the two planets is from HI.
But the image of the Sun is definitely not in visible light. I knew right away it was either in ultraviolet or X-ray; the Sun writhes and fumes under its intense magnetic fields, and that’s best seen at those higher energy forms of light.
So why is there a visible light image combined with a UV one? Instead of supposing there are higher dimensional beings warning us about the oncoming Trump presidency, I did something truly silly: I contacted some scientists involved with STEREO who might know the actual answer. Karen Fox, Joe Gurman, and Alex Young at NASA’s Goddard Space Flight Center quickly got back to me. The answer is pretty simple, and makes perfect sense: Sometimes, the image processor onboard STEREO gets overloaded, and becomes “confused.” When that happens, the images get corrupted, and sometimes two images from two different cameras get combined.
That’s precisely what happened here. The HI image was combined with one from the Extreme Ultraviolet (aha!) Imager, producing the bizarre image seen. EUVI takes images at various wavelengths of UV light (think of them as different colors), and this one is from a 17.1 nanometer image, which is where highly energized iron atoms emit. These trace the Sun’s activity well, and that’s why the image shows so many interesting features. The bright spot is where magnetic activity is especially intense, most likely due to a sunspot.
I found an EUVI image from around the same time as the weird one. The features were very similar. I rotated and flipped it to match the HI image (different cameras have different orientations and readout directions); here they are side by side.
Not-so-incidentally, each wavelength seen by EUVI is displayed using a different color to help distinguish them. They aren’t true colors—our eyes can’t see in the ultraviolet—but done as a way to easily identify each wavelength and keep them straight. The EUVI 17.1 nm images are colored blue. So it’s not a “huge blue sphere.” It’s a huge ultraviolet one that’s been colored blue.
AKA the Sun.
So there you have it. No conspiracy, no higher power. Just a glitchy computer.
Of course, another way to think about it is this: It’s a glitchy computer in a space probe launched in 2006 on a huge rocket that took it around the Earth’s orbit to the other side where it uses a complex and sophisticated suite of powerful scientific instruments to track our Sun in wavelengths invisible to the human eye so that we can better understand what it’s like to live in the outer atmosphere of one of the Universe’s most mighty denizens: a full-blown star.
Reality is WAY cooler than nonsense.
What the Heck Is Going on at the North Pole?
I’ve written quite a bit over the past few years about the death spiral of sea ice at the North Pole. Every year the amount of ice goes up and down with the seasons, growing in winter and declining in summer. But, on top of that there has been a trend downward, such that year by year we see less ice all the time.
Because of that we tend to see records set nearly every year. For example, this year in March the Arctic sea ice reached its maximum extent,* but it was the lowest maximum extent ever seen since satellite records began in 1979.
Starting in September every year the ice begins to reform, growing to a maximum. It reached that point on Sept. 10 this year, when it had the second lowest extent on record. After that day, though, it started to grow again.
Except … it didn’t. It started to, but then in early October the growth just stopped. A couple of weeks later it started to rise again, but stalled a second time in late October. In the weeks since then the amount of ice has actually fallen a bit. We are now at record low ice for this time of year, and have been for weeks.
Mind you, it’s winter up there. The Sun shines at most a few hours a day at the southern edge of the Arctic Circle right now. Yet temperatures in the Arctic are soaring; in mid-November it was an average of a staggering 22° Celsius, or 40° Fahrenheit, above normal.
Holy cripes. What the hell is going on?
The obvious answer is: global warming. Like I said, as time goes on, average temperatures go up, and amount of ice decreases.
But there’s a less obvious but more important answer, too. And that is: global warming.
That’s not a typo. The proximate cause of the temperature spike has been a weak jet stream. That blows around the pole, and generally keeps the cold air up there and the warm from the south away. But the jet steam has been weak lately, and warm air has been able to push up into the Arctic and keep temperatures up.
So why is the jet stream weak? Yup. It’s global warming. One thing that powers the jet stream is the difference in temperature between mid-latitudes and the more northern ones. As the planet warms, that difference has fallen (the Arctic warms faster than lower latitudes do), and that has weakened the jet stream.
But there’s more. Because the planet is warming, the sea surface temperatures are going up as well. Water that’s usually frigid in October (like the East Siberian and Barents Seas) has been warmer, so ice growth is slow.
There’s a subtle thing happening here too that’s important. It’s not just that we’re seeing slower ice growth, but the high temperatures are actually melting old, thick ice as well. So it’s not just the extent that’s dropping, it’s the volume as well. That’s important because thin ice comes and goes, melting faster in the summer, but the old thick ice should be here to stay. That’s no longer the case; we’re losing that too.
Here are two videos showing that. The first, from NASA, shows a map of Arctic ice over the years:
The second, by Andy Lee Robinson, shows this even more clearly using a graphical approach:
I have to add that another graph has been making the rounds, showing the total global sea ice extent. It’s troubling as well, but it comes with a caveat. Here’s the graph:
This follows the amount of sea ice at both poles, Arctic and Antarctic. It’s not really a good way to understand what’s happening because the physical conditions at the two poles are very different, and the amount of ice at each is ruled by different circumstances. Combining them just confounds all this.
Right now it’s approaching summer in the Southern Hemisphere, and we expect Antarctic ice to decline. However, even so, it’s falling faster than usual, and the extent there is lower than normal, too.
I include this graph because so many people are talking about it, and it’s important to understand that scientists don’t usually combine the two poles into one graph that way.
However there’s a second point to make as well. Whenever I write about Arctic ice, a herd of climate change deniers converge in the comments and on social media, barking about how Antarctic sea ice is unchanged or even on the rise. But—shocker—that’s crap. The two are unrelated; Antarctic sea ice tends to be relatively steady year to year, and, as you can see, despite that it is pretty low right now.
And they also ignore the fact that Arctic ice has been steadily decreasing for decades. Well, steadily until the past few weeks.
It’s possible that the boreal ice will get its act together and start growing again this season. It’s also possible it won’t. Time will tell.
But time is not on our side. It’s entirely possible we’ll see our first ice-free Arctic summer in just a few decades. Not centuries, or even a century. But maybe by 2040.
The reason this is a concern is twofold. One is that as the northern ice melts, it dumps a lot of fresh water into the oceans. This changes the salinity of the oceans, and that changes how the water flows from the Arctic to the equator and back again. This heat exchange powers a lot of our climate and weather, so having this break down is, in a word, terrifying.
Second, the Arctic is our climate canary-in-a-coal-mine. Because it’s so sensitive to warming, studying it shows us what we’re in for as our planet inexorably heats up.
*Extent is a term climate scientists use, and it’s a little different than just the area of the ice. When they measure the ice they divide the area into regions, and if a region is more than 15 percent ice they say it’s ice-covered.
This Is NOT the Milky Way. Except It Is.
In 2013, the European Space Agency launched the Gaia astronomical observatory. Its mission: Map the positions and motions of a billion stars in our galaxy. Yes, a billion.
The first data release was pretty cool, and some of the early release images were lovely as well. In 2015 the ESA released a nifty map of the Milky Way generated by Gaia data, but it wasn’t actually a photograph: They used engineering data from the observatory itself to map out where stars in the sky were, with denser patches mapped as brighter. Because the image is large and the resolution high, it looks like a photo.
Zen Pencils Takes on Science, Religion, and Relativity
Regular readers may be familiar with Gavin Aung Than’s wonderful web comic Zen Pencils: He takes famous quotations (or quotations from famous people, or just really, really good quotations) and draws a comic around them, illustrating them in ways that augment and expand their meaning*.
In a recent comic, he illustrated the wonderful words of Albert Einstein, who was describing how a sense of mystery is the foundation of both religion and science. Than uses a perhaps anecdotal scene where Einstein saw a man fall from a tree, which gave him the idea of the Equivalence Principle— that accelerating due to gravity and simply undergoing a force are the same thing.
I suggest you read the whole thing, as it’s lovely. Einstein commonly waxed poetic at the profound nature of science, and its fundamental ability to help us understand the Universe, and when he did he was quite moving.
And yet, I have to quibble with the Good Doctor. It’s a good quotation, but I don’t think mystery is the foundation of religion. I am not an historian, but from my own readings it seems to me that mystery was the jumping off point of most religions; the desire to explain the things we see around us and to answer the big questions.
But for most religions today, they claim to have the answers, and that removes the mystery. Oh, sure, there are bits about “God moving in mysterious ways” and other passages in religious texts, but these have always struck me as telling their adherents not to question, not to wonder why. Just accept.
Not all religions are like that, of course, and many religions have sects and subsects with different interpretations of their holy books and how to implement their words.
But what I like about science is that it doesn’t claim to have answers. It has methods. Yes, we do get answers, and many times they’re pretty solid. But science is all about leaving a little bit of room for further data, for an observation that doesn’t fit, for some new discovery to append or upend what we already know. Newton overturned Aristotle, and Einstein himself put Newton’s work into a larger framework; he didn’t negate it, but put it in context and showed where it could be more accurate.
I also quibble with Einstein’s phrasing, “This is religiousness.” In my opinion a better word for that would be numinous, which is arousing spiritual emotion. That’s different than actual religiousness in my book.
But like I said, these are quibbles. His point is solid, and I agree with it: There is a depth and profundity to science for those who pursue it honestly and with an open mind. The language of the Universe is written in the behavior of the Universe; science and math are how we read it.
* Full disclosure: He also made a comic out of one of my own blog posts, making it approximately a bazillion times better.
The Supermoon and Global Warming: A Taste of Things to Come
There is one real thing about the “Supermoon”: It causes flooding. But it needs help in the form of global warming.
I wrote about the so-called “Supermoon” on Monday. The basic idea is that we get a “Suupermoon” when the Moon is full at the same time it’s also at its closest point to Earth in its orbit. According to the lore, the Moon will look bigger and be brighter.
While technically true, these claims tend to be overhyped and breathless, leaving people thinking they’ll see a ginormous Moon in the sky. That’s not the case; as I point out in the article earlier this week the “Supermoon” is only about 10 percent closer than it is when it’s at apogee (the farthest point in its orbit from Earth). You’d never notice the difference in size unless you measure it. It does get brighter, by about 20 - 30 percent, which again is tough to notice on your own.
But there is one thing I didn’t mention in that article, and this is a very real and potentially disastrous effect: Tides.
Time and Tides
Tides are complicated. How they work has been argued for centuries (Newton tackled them back in the 1600s!), but in the end it has to do with the way gravity works. I go over this in detail in my episode of Crash Course Astronomy: Tides:
Here’s a quick overview: The strength of gravity weakens with distance, so the Moon’s gravity pulls harder on the near side of the Earth closer to the Moon than the far side. This stretches the Earth a bit, making it somewhat egg-shaped. Measured from the center of the Earth, both the near and far side of the Earth bump outward a bit, pulled up by the Moon’s gravity. The way gravity works, these are places of lower gravitational potential, so fluids will flow in those directions. Water is a fluid, so it flows to these points, creating high tides, one at each “end” of the Earth. That’s why we get two high tides per day; the Earth’s rotation sweeps you past these two high tide points every day.
During a “Supermoon”, the Moon is closer to Earth. Its apparent size in the sky grows as distance shrinks — make the Moon 10 percent closer and it looks 10 percent bigger. Its brightness grows as the inverse square of the distance — make it 10 percent closer and it looks 1.1 x 1.1 = 1.21 = ~20 percent brighter.
But tides work with the cube of distance, so if the Moon is 10 percent closer the tides are 1.1 x 1.1 x 1.1 = 30 percent higher than when the Moon is farther away. The higher high tides we get when the Moon is close are called proxigean tides, and they happen every month. The unusually close Moon on Nov. 14 meant they were somewhat higher than normal, even for regular proxigean tides.
But there’s more. The Sun creates tides on the Earth, too. It’s far more massive than the Moon, but much farther away, so in the end contributes about half as much to the tides on Earth as the Moon does. When the Moon and Sun are in a line these forces all add up, creating even higher high tides (and lower low tides) than usual. We call these “spring tides”, and they happen twice a month, when the Moon is full and when it’s new.
So the “Supermoon” pulled a double whammy: It was closer than usual, and full, so tides were especially high earlier in the week. We had, and still this week are still having, proxigean spring tides.
The Rising Seas
If things were normal, that would be bad enough. Coastal areas prone to flooding see higher tides twice a month due to spring tides, and also higher tides once a month from the proxigean tides. When they line up it’s worse, but generally not catastrophic.
Unless, that is, a third force comes along. For example, if this happens when there’s a storm, off shore, things can get very bad. Low-pressure systems (like hurricanes or just big storms) draw water toward their centers. If one comes ashore, this can create a storm surge, inundating low-lying areas.
But there’s yet another factor here, and it’s the most pernicious of all: sea level rise.
Global warming is melting ice at the poles (yes, at both poles), and also causing water in the oceans to expand. This is causing the sea levels to rise up over time, by about three millimeters per year. That may not sound like much, but it adds up, year after year. It’s risen 85 mm — over three inches — just since 1993!
As Tamino points out at the Open Mind blog, this alone is enough to cause flooding in coastal areas like Miami and Boston during a normal high tide.
Proxigean tides aren’t normal; they are extra strong. That’s why the NOAA issued a coastal flood warning not just for Monday but for this whole week up until tonight. It’s not until then that the Moon moves away enough both from the Earth and the Earth/Sun line to weaken tides sufficiently to relent on flooding.
But there was flooding, in Portland, Maine, Charleston, South Carolina, and many other locations. From what I can find it was bad but not devastating. It’s what Tamino calls nuisance flooding, and — pardon the expression — it’s on the rise.
In other words, and to be very clear: Global warming is causing sea level rise, which is causing more flooding all the time, and it will get worse. A lot worse.
Remember the “superstorm” Sandy that hit New York City in 2012? It caused huge amounts of damage to flooding, and was itself linked to climate change. It also happened during a full Moon, when tides were worse. Every millimeter of sea level was important there; had it been a proxigean tide as well damage would have been even worse. As it was, it was near apogee (about 400,000 km away) so at least in that sense the effect was minimized. But sea level rise played a critical role there in the flooding.
Moon with a View
I’ve been saying the Supermoon is almost all hype, exaggerated by media. But in this case it really does have an effect, and nature itself will amplify it more and more, year by year. Global warming is making that inevitable.
I cannot end this without stating the glaringly obvious, and doing so bluntly as well: The election of Donald Trump as President is and will be an epic disaster. I mean that literally. With a Republican President who is demonstrably easy to influence, cabinet choices that are the height of assininery, and a Republican Congress all too willing to deny global warming and obstruct any and all attempts to do anything to mitigate it, we are facing a threat to our national security, our nation, and our way of existence. Every year, every month we wait to take action, has huge ramifications down the road.
It’s up to all of us to stay vigilant, and to act as resistance to the denial of reality by the GOP. We have just been handed a big setback, and one with global ramifications, but — hopefully — it won’t be forever.
Ice Crystals Above Clouds Dance to the Tune of Electricity
It looks like the cloud itself is writhing!
After I saw the video, I contacted a meteorologist I knew, and he was able to find the probable cause.
First, clouds can generate enormous electric fields, generally due to rising and falling ice crystals rubbing against each other. The charges separate, and if enough of them build up, they reconnect electrically—via lightning. A typical bolt of lightning can have tens of thousands of amps of current flowing, which is a lot.
Sometimes, long, needlelike ice crystals form in the air above a cloud. They can get an electrostatic charge, like when you rub a balloon against your hair. When they do, they tend to align themselves along the electric field of the cloud. When a lightning bolt discharges, the electric field of the cloud changes suddenly. This changes the orientation of the ice crystals all at once, so what you see is a flash of light whipping around. The general name for this effect is a crown flash (though it’s sometimes called a jumping sundog; “sundog” is itself a nickname for parhelia, bright spots 22° away from the Sun and parallel to the horizon, caused by ice crystals reflecting sunlight).
At least, this is what has been supposed. A new paper in the open-access Journal of Applied Mathematics and Physics put this to the test. They modeled the ice crystals using a ferrofluid, mineral oil with tiny iron-based nanoparticles suspended in it. When a magnetic field is applied, the particles line themselves along it, forming bizarre and lovely shapes. Here’s a cool video (unrelated to the cloud research) showing how they work:
In this new work, the scientists bounced a laser (representing sunlight) off a ferrofluid, and showed that the direction in which the beam got reflected changed as they repositioned the magnet, and it happened in a similar way as the real crown flashes above clouds. While this doesn’t prove the proposed explanation, it strongly supports it, and I find this hypothesis pretty compelling.
I’ve never seen a crown flash myself; they’re pretty rare, and the geometry has to be just right to create them. Maybe someday.
But I do get a consolation prize. The reason I heard about this research is that I was notified by the paper’s lead author Alberto Tufaile on Twitter. It turns out he found out about the phenomenon by reading my article on it! He and his team even reference it in the paper:
(That was from when my blog was hosted by Discover Magazine, if you’re curious; I moved to Slate in 2013.)
How cool is that? I don’t think my blog has ever been cited in a science paper before, much less been the starting point for the research itself! And, why yes, before you ask, I am pretty chuffed with myself over that.
But the real takeaway here is that there is stuff going on literally right over our heads that we still don’t fully understand, and may not even know about yet. So—and I bet you know what I’m about to say here:
Look up! You never know what you might see.