## The First Film Footage of a Total Solar Eclipse (1900)

The BFI and the Royal Astronomical Society have recently rediscovered and restored a film taken in 1900 of a total solar eclipse. Here’s the minute-long film on YouTube:

The film was taken by British magician turned pioneering filmmaker Nevil Maskelyne on an expedition by the British Astronomical Association to North Carolina on 28 May, 1900. This was Maskelyne’s second attempt to capture a solar eclipse. In 1898 he travelled to India to photograph an eclipse where succeeded but the film can was stolen on his return journey home. It was not an easy feat to film. Maskelyne had to make a special telescopic adapter for his camera to capture the event. This is the only film by Maskelyne that we know to have survived.

The Royal Astronomy Society will be showing the film tomorrow May 31 at their HQ in London as part of their celebration of the centenary of the 1919 eclipse; free tickets available here.

See also my account of going to see the 2017 solar eclipse, one of the coolest things I’ve ever done. (via @UnlikelyWorlds)

## Actually, Mercury Is Our Closest Planetary Neighbor

If you look at the orbits of the planets adjacent to the Earth’s orbit (Venus & Mars), you’ll see that Venus’s orbit is closest to our own. That is, at its closest approach, Venus gets closer to Earth than any other planet. But what about the average distance?

According to this article in Physics Today by Tom Stockman, Gabriel Monroe, and Samuel Cordner, if you run a simulation and do a proper calculation, you’ll find that Mercury, and not Venus or Mars, is Earth’s closest neighbor on average (and spends more time as Earth’s closest neighbor than any other planet):

Although it feels intuitive that the average distance between every point on two concentric ellipses would be the difference in their radii, in reality that difference determines only the average distance of the ellipses’ closest points. Indeed, when Earth and Venus are at their closest approach, their separation is roughly 0.28 AU — no other planet gets nearer to Earth. But just as often, the two planets are at their most distant, when Venus is on the side of the Sun opposite Earth, 1.72 AU away. We can improve the flawed calculation by averaging the distances of closest and farthest approach (resulting in an average distance of 1 AU between Earth and Venus), but finding the true solution requires a bit more effort.

What the calculation also shows is that Mercury is the closest planetary neighbor to every planet, on average. Also, the authors of the paper don’t explicitly mention this, but the Sun (at 1 AU) is closer on average to the Earth than even Mercury (1.04 AU).

## Sunshine Considered Harmful? Perhaps Not.

For Outside magazine, Rowan Jacobsen talks to scientists whose research suggests that the current guidelines for protecting human skin from exposure to the sun are backwards. Despite the skin cancer risk, we should be getting more sun, not less.

When I spoke with Weller, I made the mistake of characterizing this notion as counterintuitive. “It’s entirely intuitive,” he responded. “Homo sapiens have been around for 200,000 years. Until the industrial revolution, we lived outside. How did we get through the Neolithic Era without sunscreen? Actually, perfectly well. What’s counterintuitive is that dermatologists run around saying, ‘Don’t go outside, you might die.’”

When you spend much of your day treating patients with terrible melanomas, it’s natural to focus on preventing them, but you need to keep the big picture in mind. Orthopedic surgeons, after all, don’t advise their patients to avoid exercise in order to reduce the risk of knee injuries.

Meanwhile, that big picture just keeps getting more interesting. Vitamin D now looks like the tip of the solar iceberg. Sunlight triggers the release of a number of other important compounds in the body, not only nitric oxide but also serotonin and endorphins. It reduces the risk of prostate, breast, colorectal, and pancreatic cancers. It improves circadian rhythms. It reduces inflammation and dampens autoimmune responses. It improves virtually every mental condition you can think of. And it’s free.

These seem like benefits everyone should be able to take advantage of. But not all people process sunlight the same way. And the current U.S. sun-exposure guidelines were written for the whitest people on earth.

Exposure and sunscreen recommendations for people with dark skin may be particularly misleading.

People of color rarely get melanoma. The rate is 26 per 100,000 in Caucasians, 5 per 100,000 in Hispanics, and 1 per 100,000 in African Americans. On the rare occasion when African Americans do get melanoma, it’s particularly lethal — but it’s mostly a kind that occurs on the palms, soles, or under the nails and is not caused by sun exposure.

At the same time, African Americans suffer high rates of diabetes, heart disease, stroke, internal cancers, and other diseases that seem to improve in the presence of sunlight, of which they may well not be getting enough. Because of their genetically higher levels of melanin, they require more sun exposure to produce compounds like vitamin D, and they are less able to store that vitamin for darker days. They have much to gain from the sun and little to fear.

## “The eclipse was not black but some other color that screamed evil”

Even two months later, I’m still reeling from seeing the total solar eclipse. When I think about that day and those two minutes, a chill goes right down my spine. Vi Hart, who took part in Atlas Obscura’s eclipse festival in Oregon, wrote a beautifully poetic piece about witnessing the eclipse that took me right back there.

I’m not sure exactly what I expected, but this wasn’t it. I’d seen photos of coronas around suns, but this wasn’t that. And I’d expected that those photos, like many astronomical pictures, are long exposure, other wavelengths, and otherwise capturing things the naked eye can’t see. I thought there might be a glow of light in a circle, or nothing, or, I don’t know. What I did not expect was an unholy horror sucking the life and light and warmth out of the universe with long reaching arms, that what I’d seen in pictures was not an exaggeration but a failure to capture the extent of this thing that human eyes, and not cameras, are uniquely suited to absorb the horror of.

I protest the idea that the sun, or the moon, or the hole in the universe where the sun was ripped away from us, was black. It was not black. It was a new color, perceivable to the human eye only in certain conditions. I’ve read the literature on color perception and color philosophy. I’ve got the ontological chops. I feel qualified to make this statement, that this thing in the sky was not black. I could understand why people would describe it as black, just as without a word for red you might describe blood as black. But it wasn’t, and so no photograph could possibly capture what it’s like, and no screen can yet display it.

(thx, geoff)

## The Astronomy Photographer of the Year for 2017

Put on by the Royal Observatory Greenwich, The Astronomy Photographer of the Year is the largest competition of its kind in the world. For the 2017 awards, more than 3800 photos were entered from 91 countries. It’s astounding to me that many of these were taken with telescopes you can easily buy online (granted, for thousands of dollars) rather than with the Hubble or some building-sized scope on the top of a mountain in Chile.

The photos above were taken by Andriy Borovkov, Alexandra Hart, and Kamil Nureev.

## What would happen if you brought a tiny piece of the Sun to Earth?

Kurzgesagt asks and answers the question: what happens if we bring the Sun to the Earth? Since the density and makeup of the Sun varies, they go over scenarios of sampling a house-size chunk from four different spots of the Sun: the chromosphere, the photosphere, the radiative zone, and the core. The answers range from “not much” to “well, that was a terrifically bad idea”.

## My 2017 total solar eclipse trip

I was not prepared for how incredible the total eclipse was. It was, literally, awesome. Almost a spiritual experience. I also did not anticipate the crazy-ass, reverse storm-chasing car ride we’d need to undertake in order to see it.

I’m not a bucket list sort of person, but ever since seeing a partial eclipse back in college in the 90s (probably this one), I have wanted to witness a total solar eclipse with my own eyes. I started planning for the 2017 event three years ago…the original idea was to go to Oregon, but then some college friends suggested meeting up in Nebraska, which seemed ideal: perhaps less traffic than Oregon, better weather, and more ways to drive in case of poor weather.

Well, two of those things were true. Waking up on Monday, the cloud cover report for Lincoln didn’t look so promising. Rejecting the promise of slightly better skies to the west along I-80, we opted instead to head southeast towards St. Joseph, Missouri where the cloud cover report looked much better. Along the way, thunderstorms started popping up right where we were headed. Committed to our route and trusting this rando internet weather report with religious conviction, we pressed on. We drove through three rainstorms, our car hydroplaning because it was raining so hard, flood warnings popping up on our phones for tiny towns we were about to drive through. Morale was low and the car was pretty quiet for awhile; I Stoically resigned myself to missing the eclipse.

But on the radar, hope. The storms were headed off to the northeast and it appeared as though we might make it past them in time. The Sun appeared briefly through the clouds and from the passenger seat, I stabbed at it shining through the windshield, “There it is! There’s the Sun!” We angled back to the west slightly and, after 3.5 hours in the car, we pulled off the road near the aptly named town of Rayville with 40 minutes until totality, mostly clear skies above us. After our effort, all that was missing was a majestic choral “ahhhhhh” sound as the storm clouds parted to reveal the Sun.

My friend Mouser got his camera set up — he’d brought along the 500mm telephoto lens he uses for birding — and we spent some time looking at the partial eclipse through our glasses, binoculars (outfitted with my homemade solar filter), and phone cameras. I hadn’t seen a partial eclipse since that one back in the 90s, and it was cool seeing the Sun appear as a crescent in the sky. I took this photo through the clouds:

Some more substantial clouds were approaching but not quickly enough to ruin the eclipse. I pumped my fist, incredulous and thrilled that our effort was going to pay off. As totality approached, the sky got darker, our shadows sharpened, insects started making noise, and disoriented birds quieted. The air cooled and it even started to get a little foggy because of the rapid temperature change.

We saw the Baily’s beads and the diamond ring effect. And then…sorry, words are insufficient here. When the Moon finally slipped completely in front of the Sun and the sky went dark, I don’t even know how to describe it. The world stopped and time with it. During totality, Mouser took the photo at the top of the page. I’d seen photos like that before but had assumed that the beautifully wispy corona had been enhanced with filters in Photoshop. But no…that is actually what it looks like in the sky when viewing it with the naked eye (albeit smaller). Hands down, it was the most incredible natural event I’ve ever seen.

After two minutes — or was it several hours? — it was over and we struggled to talk to each other about what we had just seen. We stumbled around, dazed. I felt high, euphoric. Raza Syed put it perfectly:

It was beautiful and dramatic and overwhelming — the most thrillingly disorienting passage of time I’ve experienced since that one time I skydived. It was a complete circadian mindfuck.

After waiting for more than 20 years, I’m so glad I finally got to witness a total solar eclipse in person. What a thing. What a wondrous thing.

Update: Here are some reports from my eclipse-chasing buddies: a photo of Mouser setting up his camera rig, Nina’s sharp shadow at 99% totality, and Mouser’s slightly out-of-focus shot of the Sun at totality (with an account of our travels that day).

## Solar eclipse myth busted: it’s perfectly safe for kids to be outside during an eclipse

Throughout history, total solar eclipses have been unnerving. To ancient cultures, they signified bad omens, the apocalypse, or that the Sun was being eaten by a sky creature.

There were a tumult, and disorder. All were disquieted, unnerved, frightened. Then there was weeping. The commonfolk raised a cup, lifting their voices, making a great din, calling out shrieking. People of light complexion were slain as sacrifices; captives were killed. All offered their blood.

But even in modern times, a lack of scientific understanding of what happens during a solar eclipse can cause apprehension and panic. Until hearing the same story from two different people in the past week, I had no idea that during solar eclipses, it is routine for schoolchildren to be kept inside until the “danger” has passed. Charles Fulco, a NASA and AAS 2017 U.S. Eclipse Educator, is trying to allay these fears by addressing common eclipse misconceptions.

“The Sun is more dangerous during an eclipse.” This is utter nonsense and for some reason, has persisted into the 21st Century. An eclipsed Sun is no more dangerous than the “everyday” Sun, but for some reason, some districts still keep teachers and students in their rooms with pulled shades, watching the eclipse on a screen, rather than outdoors, safely and under the care of a professional educator. I believe their fear of nature is transferred to the students as well: If the adult says an eclipse is scary and dangerous, than it must be!

As I make my final preparations for my eclipse travels (rural western Wyoming, if you’re curious) I’m hearing stories that are making me very unhappy: Some school districts across the country are telling children to stay inside during the eclipse, out of fear they’ll damage their eyes.

Let me be clear: Schools, administrators, teachers, parents: Don’t do this. YOU CAN LET THE KIDS SEE THE ECLIPSE. You just have to be safe about it.

I can appreciate the difficulty of telling 25 first graders there’s something cool happening with the Sun and then trying to get them not to look directly at it, but keeping kids inside is not the answer. For one thing, they’re missing out on a genuine celestial spectacle & learning opportunity and for another, you’re teaching people bad science. A friend, who is one of the smartest people I know, was genuinely concerned for her kids’ safety during the eclipse because when she was a kid, she was kept inside a classroom with the shades drawn because, she was told, it was dangerous for them to be outside. Dangerous to be outside in the sunshine! A clear case of educators doing the exact opposite of what they should be doing.

## Viewing a total solar eclipse from an airplane

On March 8-9, 2016, a total solar eclipse swept across the Pacific Ocean for more than 5 hours. About a year before the eclipse, Hayden Planetarium astronomer Joe Rao realized Alaska Airlines flight 870 from Anchorage to Honolulu would pass right through the path of totality…but 25 minutes too early. Rao called the airline and convinced them to shift the flight time.

Alaska’s fleet director, Captain Brian Holm, reviewed the proposed flight path and possible in-route changes to optimize for the eclipse. The schedule planning team pushed back the departure time by 25 minutes, to 2 p.m.

On the day of the flight, Dispatch will develop the specific flight plan, to find the most efficient route and account for weather and wind. Maintenance and maintenance control will help make sure the plane is ready to go — they even washed all the windows on the right side of the plane.

Captain Hal Andersen also coordinated with Oceanic Air Traffic Control, to make them aware that the flight might require a few more tactical changes then normal.

“The key to success here is meeting some very tight time constraints — specific latitudes and longitudes over the ocean,” Andersen said. “With the flight management computer, it’s a pretty easy challenge, but it’s something we need to pay very close attention to. We don’t want to be too far ahead or too far behind schedule.”

The video was shot by a very excited Mike Kentrianakis of the American Astronomical Society, who has witnessed 20 solar eclipses during his lifetime.

July 11, 2010. That was the eclipse over Easter Island, the one for which hotel room rates were so high that there was no way Kentrianakis could afford it. Instead, he considered attempting a trip to Argentina, where experts predicted there was a 5 percent chance of clear skies. His wife at the time, Olga, urged him not to go — it’s not worth the expense, she insisted. Reluctantly, Kentrianakis stayed home.

“It was the beginning of the end for us,” Kentrianakis says. There were problems in the marriage before that episode, “but it affected me that I felt that she didn’t really appreciate what I loved.” They were divorced the following year.

Kentrianakis doesn’t like to dwell on this, or the other things he’s given up to chase eclipses. He knows his bosses grumbled about the missed days of work. Friends raise their eyebrows at the extremes to which he goes. He’s unwilling to admit how much he’s spent on his obsession.

“There is a trade-off for everything, for what somebody wants,” he says.

A camera on the Deep Space Climate Observatory satellite captured the eclipse’s shadow as it moved across the Earth:

For this year’s eclipse, Alaska Airlines is doing a special charter flight for astronomy nerds and eclipse chasers. Depending on how this eclipse goes, seeing an eclipse from an airplane might be on my bucket list for next time. (via @coudal)

## How to predict total solar eclipses

The Exploratorium in San Francisco has produced a great explainer video about the science of predicting total solar eclipses. Each eclipse belongs to a repeating series of eclipses called a Saros cycle that repeats every 18 years 11 days and 8 hours.

There are now 40 active Saros cycles and the August 2017 eclipse belongs to Saros 145, which produced its first total eclipse in June 1909 and will produce its last total eclipse in September 2648.

## A tour of our solar system’s eclipses

In a meditative video for the NY Times, Dennis Overbye takes us on a tour of eclipses that happen in our solar system and beyond.

On the 21st day of August, 2017, the moon will slide between the Earth and the sun, painting a swath of darkness across North America. The Great American Solar Eclipse. An exercise in cosmic geometry. A reminder that we live on one sphere among many, all moving to the laws of Kepler, Newton and Einstein.

Humans have many more vantage points from which to observe solar eclipses than when the last solar eclipse occurred in the US in 1979. I had no idea that the Mars rovers had caught partial solar eclipses on Mars…so cool. (via @jossfong)

## Why is the upcoming total solar eclipse such a big deal?

Well, the short answer is that they don’t happen all that often and when they do, they’ve visible from only a small bit of Earth. Joss Fong elaborates in a video for Vox.

The next total solar eclipse to visit the US will be in 2024. If an eclipse happens to come to your town, you’re lucky. Any given location will see a total solar eclipse only once in more than 300 years, on average. The vast majority of us will have to travel to an eclipse path if we want to see a total eclipse in our lifetimes.

I’m off to Nebraska in August to meet up with some friends and see the eclipse. (And that 2024 eclipse Fong mentions? The path of totality goes right over my damn house. Woooo!) But no matter where you are in North America, you can enjoy the eclipse…just make sure you buy some safety glasses (and other supplies) if you want to look directly at the Sun. (via @veganstraightedge)

## How to safely enjoy the 2017 solar eclipse, a buyer’s guide for normal people

Important update: Since I published this guide a month ago, NASA and the AAS have updated their recommendation on buying solar safety glasses due to reports of counterfeit eclipse glasses. They no longer recommend looking for the ISO rating alone but only buying from a recommended manufacturer. If you have purchased glasses or are going to purchase glasses, read this page carefully before using them, paying particular attention to this bit:

Unfortunately, you can’t check whether a filter meets the ISO standard yourself — doing so requires a specialized and expensive piece of laboratory equipment called a spectrophotometer that shines intense UV, visible, and IR light through the filter and measures how much gets through at each wavelength. Solar filter manufacturers send their products to specialized labs that are accredited to perform the tests necessary to verify compliance with the ISO 12312-2 safety specifications. Once they have the paperwork that documents their products as ISO-compliant, they can legitimately use the ISO logo on their products and packaging.

Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers haven’t been properly tested. This means that just seeing the ISO logo or a label claiming ISO 12312-2 certification isn’t good enough. You need to know that the product comes from a reputable manufacturer or one of their authorized dealers.

Amazon recently sent out emails to the buyers of the plastic-framed glasses I bought and linked to here (“habibee 4-Pack Black Plastic Eclipse Glasses CE & ISO Certified 2017 Safe Solar Eclipses Viewing Shades Block Sun Ultraviolet UV Lights Goggles”), saying that they have “not received confirmation from the supplier of your order that they sourced the item from a recommended manufacturer” and, to their credit, have automatically issued refunds to those buyers. They also appear to have removed any products from their site that aren’t sourced from a recommended manufacturer. This doesn’t necessarily mean the glasses are faulty…it just means the solar filter paper used for the lenses can’t be sourced. Again, read this page carefully before deciding to use any glasses you may have purchased. I tested a pair this morning, looking at bright light bulbs and they seem appropriately dark, but as noted by the AAS, who knows about the UV and IR filtering? I’m throwing mine out.

The cardboard-framed glasses I linked to (while currently sold out) are manufactured by American Paper Optics, which is on the AAS’s list of reputable vendors. Also on the list is the manufacturer of the solar filter sheets, Thousand Oaks Optical. The two cardboard camera lens covers I linked to have been deleted from Amazon, a sign that their sourcing cannot be verified. I’ve updated the links and text below to only include links to products on the list of reputable vendors. Most are sold out at this point anyway, so…

I wish I’d had these new NASA and AAS recommendations a month ago…I obviously would have followed them closely in making buying choices & recommendations. That some unscrupulous manufacturers are using people’s enthusiasm for science and viewing the eclipse to sell potentially harmful products makes me angry and sick to my stomach. Luckily Amazon is doing the right thing here with refunds and safety notices. And thanks to NASA and the AAS for their guidance…again please read this before using your eclipse glasses, even ones you may have gotten free from your public library or through other organizations. /end update

On August 21, 2017 across the entire United States, the Moon will move in front of the Sun, partially blocking it from our view. For those on the path of totality, the Moon will entirely block out the Sun for more than 2 minutes. I’ve been looking forward to seeing a total solar eclipse since I was a little kid, so I’ve been doing a lot of research on what to buy to enjoy the eclipse safely. Here’s what I’ve come up with.

I’ve oriented this guide toward the enthusiastic beginner, someone who’s excited about experiencing the wonder of the eclipse with their friends & family but isn’t interested in expensive specialty gear or photography (like me!). And, again, since you will be able to see this eclipse from everywhere in North America to some degree, this guide applies to anyone in the US/Canada/Mexico.

In planning for eclipse viewing, please check out NASA’s safety notes for more information. Make sure that whatever you buy, it’s properly rated for naked eye solar viewing. Looking directly at the Sun without a proper filter can cause permanent damage, particularly through binoculars, a camera lens, or a telescope.

Note: If you’re going to get eclipse supplies, now is the time. Some of this stuff will probably be very difficult to find (or very expensive) as we approach August 21 — for instance, shipping estimates on Amazon for some of the glasses are mid-August already.

Solar eclipse glasses are essential. Right up until the Sun goes completely behind the Moon (if you’re on the path of totality), you will want to look at the crescent-shaped Sun and you’ll need certified safety glasses to do so. Regular sunglasses will not work! Do not even. There are several options…find some in stock that ship soon. Note: If you have young kids, splurge for the plastic framed glasses (if you can find them…most are sold out now)…my testing indicates the cardboard ones don’t stay on smaller heads as well.

Make a pinhole viewer. A pinhole viewer will let you see the shape of the eclipsed Sun without having to look directly at it. This Exploratorium guide should get you started. All you need in terms of supplies you probably have lying around at home: aluminum foil, paper, cardboard, etc. I suspect Kelli Anderson’s This Book is a Camera (\$27) might also work if you play with the exposure times?

Apply good sunscreen. You’ve got your eye protection down, now for the rest of yourself. The eclipse is happening in the middle of the day in much of the country, in what you hope will be complete sunshine, so bring some sunscreen. The Sweethome recommends this SPF 70 Coppertone for \$9. Wear a cap. Stay in the shade. Bonus for shading yourself under trees: the gaps between the leaves will form little pinhole lenses and you’ll see really cool patterns:

A nice pair of binoculars. If you’re in the path of totality, you might want a pair of binoculars to look more closely at the totally eclipsed Sun (after checking that it’s safe!!). I’m guessing you don’t want to buy a pair of specialty astronomy binoculars, so the best binoculars are probably ones you already own. If you don’t already have a pair, The Wirecutter recommends the Midas 8 x 42 binoculars by Athlon Optics (\$290) with the Carson VP 8x42mm (\$144) as a budget pick. (For solar filter options, see below.)

A solar filter for your camera. If you have a camera, they might make a solar filter for whatever lens you want to use. Hydrogen alpha filters will allow you to see the most detail — “crazy prominences and what-not” in the words of a photography pal of mine — but are also pretty expensive. You can buy solar filter sheets (\$29) to make your own lens coverings for your camera, binoculars, or telescope. Quality will likely not be fantastic, but you’ll get something. Safety warning: place any filters in front of lenses or it can burn a hole in the filter (and then into your eye); i.e. don’t use binoculars in front of safety glasses!!

Note for budding solar photographers: Shooting the eclipse will be challenging. First there’s too much light and you’ll need a filter. Then when totality occurs, you’ll be in the dark needing a tripod and a fast lens. Plan accordingly…or leave it all at home and look at the thousands of photos taken by pro photographers after the fact.

Ok, that’s it. Have a good eclipse and stay safe!

Update: I removed a reference to the plastic-rimmed safety glasses I ordered because the image has changed on this item since I ordered them and published this guide…it’s now a wire-rimmed pair of glasses. I would recommend getting something else instead, just to be safe. (thx, @kahnnn)

Update: NASA has been alerted that some of the paper glasses being sold are not safe for viewing the eclipse. When buying, look for the ISO icon (referencing 12312-2) and for glasses made by these recommended manufacturers: American Paper Optics, Rainbow Symphony, Thousand Oaks Optical, or TSE 17. (via @ebellm)

Update: The Wirecutter has released their guide to The Best Solar Eclipse Glasses and Filters and they recommend the Celestron EclipSmart 2x Power Viewers (2-pack for \$10), which provide not only certified eye protection but a nice 2X zoom.

## Eclipse maps of the US, from 2000 BC to 100 years into the future

The Washington Post has a cool series of maps related to the total solar eclipse happening in August. The one above is a one-shot view of what the Sun will look like across the US on August 21 and there are other maps with captions like “The last eclipse over these areas occurred before Columbus’s arrival in 1492” and “Total solar eclipse paths over the continental U.S. since 2000 B.C.”

In the last 100 years, some areas have been in the paths of multiple eclipses: New England, for example, saw four. (During its World Series dry spell from 1918 to 2004, the greater Boston area alone saw two.)

Others weren’t so lucky. Just 200 miles away in New York, construction on the Empire State Building had not started yet the last time the city saw a total solar eclipse (1925). San Diego had a population of less than 100,000 the last time it was eclipsed (1923), and Chicago hasn’t seen a total eclipse at all in the last 100 years. An area near Tucson has the longest dry spell in the Lower 48: The last total solar eclipse it saw was in the year 797.

The U.S. mainland has averaged about seven total solar eclipses per century since 2000 B.C. Some areas have seen as many as 25 eclipses, while others, such as spots west of Minneapolis, have seen only four in the last four millennia.

## NASA’s super accurate map of the 2017 eclipse

Using data about the Moon’s terrain from the Lunar Reconnaissance Orbiter as well as elevation data on Earth, NASA’s Ernie Wright created a very accurate map of where and when the August 2017 eclipse will occur in the United States.

Standing at the edge of the moon’s shadow, or umbra, the difference between seeing a total eclipse and a partial eclipse comes down to elevation — mountains and valleys both on Earth and on the moon — which affect where the shadow lands. In this visualization, data from NASA’s Lunar Reconnaissance Orbiter account for the moon’s terrain that creates a jagged edge on its shadow. This data is then combined with elevation data on Earth as well as information on the sun angle to create the most accurate map of the eclipse path to date.

See also Eclipse Megamovie 2017, an eclipse simulator you can use to check what the eclipse will look like in the sky in your area, and what looks like an amazing eclipse watching festival put on by Atlas Obscura.

## Epic time lapse videos of Mercury’s transit of the Sun

About 13 times per century, the planets align in the heavens and the Earth can watch Mercury crossing the face of the Sun. NASA’s Solar Dynamics Observatory was watching too and captured time lapse videos from several angles using various instruments measuring magnetism, visible light, and UV. The cosmic ballet goes on.

See also more from the SDO: a gorgeous time lapse of the Sun, a three-year video portrait of the Sun, and Thermonuclear Art.

## Time lapse video of a year’s worth of sunrises

A man in Germany rigged a camera to take a photo 10 minutes after sunrise every day for an entire year. Phil Plait explains the Sun’s motion:

The video starts at the vernal equinox in 2015, on March 21, and runs through to March 20, 2016. The Sun rises due east, then moves left (north) every morning at a rapid rate. You can then see it slow, stop at the June solstice, and then reverse direction, moving south (right). It slows and stops again at the December solstice (note the snow on the rooftops!), then reverses, moving north again. The weather gets pretty bad, but you can still see enough to get a sense that the Sun moves most rapidly at the equinoxes and most slowly at the solstices, just as I said.

## Satellite view of a total eclipse

The Japanese satellite Himawari caught yesterday’s total solar eclipse as it moved across the Pacific Ocean.

Update: @paulmison sent along some better views of the eclipse: here and here. I tried to find a better YouTube embed, but no dice. This one, taken of the eclipse in Micronesia, is pretty amazing though…you can see the solar flares coming off the surface of the Sun as it reaches totality. Holy shit, I’m getting excited for Eclipsathon 2017!

## Forecasting awesome sunsets

A team of three Pennsylvania meteorologists is now providing a coast-to-coast sunset quality forecast.

The team behind SunsetWx has already published a thorough methodology of its algorithm and a case study of successfully predicted “vivid” sunsets its first day of forecasting last week. Basically, the model blends high-resolution forecasts of humidity, pressure changes, and clouds at various levels of the atmosphere, weighting wispy upper-level clouds the strongest and penalizing for thick, low-level clouds or average clear sky evenings.

They totally called Sunday’s bonkers NYC sunset, so maybe they’re worth a follow. Sunset photo by @AirlineFlyer.

## Thermonuclear Art

In a nod to our nation’s recreational drug users, NASA has created this 30-minute ultra high-resolution look at our Sun, assembled from thousands of photographs taken by the Solar Dynamics Observatory, which snaps a 16-megapixel image of the Sun every few seconds. Duuuuuuuude…

## Hand-drawn animation of 43 years of the Sun’s weather

Artist and programmer Jeff Thompson has compiled 15,000 hand-drawn maps of the Sun made by astronomers into a single video, creating a mesmerizing and delightfully makeshift stop-motion animation of the Sun’s activity over the last 43 years. Astronomers have been drawing these “solar synoptic maps” since 1956 in order to keep track of the Sun’s “weather”…sunspots, flares, and the like. (via slate)

## Supermassive black holes are *really* massive

How massive are they? The Sun is 1 solar mass and as wide as 109 Earths. Sagittarius A, the black hole at the center of the Milky Way, weighs 4.3 million solar masses and is as wide as Mercury is far from the Sun. The black hole at the center of the Phoenix Cluster is one of the largest known black holes in the Universe; it’s 73 billion miles across, which is 19 times larger than our entire solar system (from the Sun to Pluto). As for how much it weighs, check this out:

I also like that if you made the Earth into a black hole, it would be the size of a peanut. (thx, reidar)

## Flying through an eclipse

A group of astronomy enthusiasts rented a plane and flew through the shadow cast by the recent eclipse of the Sun. One passenger took the following video. Look at that shadow creeping across the cloud cover! So cool.

P.S. Still super excited for the 2017 eclipse! (via slate)

## Replacement Suns

From the Russian Space Agency, a video of what the sky would look like if the Sun were replaced by some other stars. It starts off with the binary star system of Alpha Centuri, but watch until the end for Polaris, which has a radius 46 times that of the Sun.

## Is it possible to extinguish the Sun with water?

From Quora, an answer to the question “If we pour water on the sun with a bucket as big as the sun, will the sun be extinguished?”

The probable answer is “no.” The Sun involves a special type of fire that is able to “burn” water, and so it will just get hotter, and six times brighter.

Water is 89% oxygen BY MASS. And the Sun’s overall density is 1.4 times that of water. So if you have a volume of water the VOLUME of the Sun, it will have 1/1.4 = 0.71 times the mass of the Sun, and this mass will be .71*.89 = 63% of a solar mass of oxygen and 8% of a solar mass of hydrogen. The Sun itself is 0.74 solar masses of hydrogen and 0.24 solar masses of helium.

So you end up with a 1.7 solar mass star with composition 48% hydrogen, 37% oxygen, and 14% helium (with 1% heavier elements).

Now, will such a star burn? Yes, but not with the type of proton-proton fusion the Sun uses. A star 1.7 times the mass of the Sun will heat up and burn almost entirely by the CNO fusion cycle, after making some carbon and nitrogen to go along with all the oxygen you’ve started with. So with CNO fusion and that mass you get a type F0 star with about 1.3 times the radius and 6 times the luminosity of the present Sun, and a temperature somewhat hotter than the Sun (7200 K vs. the Sun’s 5800 K). It will be bluish-white, with more UV. That, along with that 6 times heat input, will cause the Earth’s biosphere to be fried, and oceans to probably boil.

Well, we probably shouldn’t do that then. (via gizmodo)

## Gorgeous time lapse of the Sun

This is a time lapse of the surface of the Sun, constructed of more than 17,000 images taken by the Solar Dynamics Observatory from Oct 14 to Oct 30, 2014. The bright area that starts on the far right is sunspot AR 12192, the largest observed sunspot since 1990.

The sunspot is about 80,000 miles across (as wide as 10 Earths) and it’s visible from Earth with the naked eye. Best viewed as large as possible…I bet this looks amazing on the new retina iMac. (via @pageman)

## The 2017 total solar eclipse awarded to the United States

I do not officially have a bucket list1 but if I did have one, watching a total solar eclipse would be on it. Was just talking about it the other day in fact. Well. I am pretty damn excited for the Great American Eclipse of 2017!

In August 21, 2017, millions of people across the United States will see nature’s most wondrous spectacle — a total eclipse of the Sun. It is a scene of unimaginable beauty; the Moon completely blocks the Sun, daytime becomes a deep twilight, and the Sun’s corona shimmers in the darkened sky. This is your guide to understand, prepare for, and view this rare celestial event.

It goes right through the middle of the country too…almost everyone in the lower 48 is within a day’s drive of seeing it. Cities in the path of the totality include Salem, OR, Jackson, WY, Lincoln, NE, St. Louis, MO (nearly), Nashville, TN, and Charleston, SC.

Weather will definitely play a factor in actually seeing the eclipse, so I will be keeping an eye on Eclipser (“Climatology and Maps for the Eclipse Chaser”) as the event draws near. Early analysis indicates Oregon as the best chance for clear skies. Matt, I am hereby laying claim to your guest room in three years time. So excited!!

1. Also on this hypothetical bucket list: dunking a basketball, going to outer space, learning to surf, and two chicks at the same time.

## A canyon of fire on the Sun

NASA’s Solar Dynamics Observatory is getting some really amazing shots of the Sun, including this 200,000 mile-long solar eruption that left a huge canyon on the surface of the Sun:

Different wavelengths help capture different aspect of events in the corona. The red images shown in the movie help highlight plasma at temperatures of 90,000° F and are good for observing filaments as they form and erupt. The yellow images, showing temperatures at 1,000,000° F, are useful for observing material coursing along the sun’s magnetic field lines, seen in the movie as an arcade of loops across the area of the eruption. The browner images at the beginning of the movie show material at temperatures of 1,800,000° F, and it is here where the canyon of fire imagery is most obvious.

The level of detail shown is incredible. (via @DavidGrann)

## ISS in transit

Romanian photographer Maximilian Teodorescu recently caught the International Space Station in transit across the Sun.

Teodorescu has also taken photos of the ISS in transit across the Moon.

These photos make the ISS seem tiny and huge all at the same time. And be sure to click through on the links to see the full-sized photos.

## The Sun telescope

Turning the Sun into a giant radio telescope through gravitational lensing will take some work, but it is possible.

An Italian space scientist, Claudio Maccone, believes that gravitational lensing could be used for something even more extraordinary: searching for radio signals from alien civilizations. Maccone wants to use the sun as a gravitational lens to make an extraordinarily sensitive radio telescope. He did not invent the idea, which he calls FOCAL, but he has studied it more deeply than anyone else. A radio telescope at a gravitational focal point of the sun would be incredibly sensitive. (Unlike an optical lens, a gravitational lens actually has many focal points that lie along a straight line, called a focal line; imagine a line running through an observer, the center of the lens, and the target.) For one particular frequency that has been proposed as a channel for interstellar communication, a telescope would amplify the signal by a factor of 1.3 quadrillion.