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kottke.org posts about astronomy

Gorgeous computer-generated animation of a nebula

posted by Jason Kottke   Nov 07, 2017

Designed by Teun van der Zalm, Nebulae is a computer generated nebula set to atmospheric music by Lee Rosevere. Worth seeking out a large screen for viewing. Several of van der Zalm’s other videos are equally beautiful variations on the same theme.

The 100-megapixel Moon

posted by Jason Kottke   Nov 06, 2017

100 Megapixel Moon

Seán Doran used images from the Lunar Reconnaissance Orbiter to create this 100-megapixel image of the Moon (full 10000x10000 pixel image here). Phil Plait explains how Doran made the image:

LRO WAC images have a resolution of about 100 meters per pixel over a swath of about 60 km of lunar surface (using what’s called the pushbroom technique, similar to how a flatbed scanner works). They are usually taken straight down, toward the spacecraft nadir (the opposite of the zenith). To get the correct perspective for the Moon as a globe, Doran took the images, along with altimeter data, and mapped them onto a sphere. That way features near the edge look foreshortened, as they really do when you look at the entire Moon. He also used Apollo images to make sure things lined up. So the image isn’t exactly scientifically rigorous, but it is certainly spectacular.

The image is also available at Gigapan for easier exploration.

The Universe is much bigger than it is old

posted by Jason Kottke   Oct 20, 2017

In a Twitter thread, author Oliver Morton compares the physical scale of the Universe with its age (from the perspective of humans).

If a human life is 70 years long, there has been room for 200 million lives since the big bang, but 200 million humans, end to end, would reach just a bit further than the moon. If you had started walking towards the centre of the galaxy on the day of the big bang (had there been days, you, paths & galaxies), you would have got about 20 parsecs by now: just 0.25% of the way.

Maybe walking pace is the wrong metric. A nerve impulse travels around 70 times faster than a person walks. But even at the speed of thought, the age of the universe is too small for something to have reached the centre of the galaxy.

The situation is even worse when you choose another reference object, like UY Scuti, the largest known star. The red hypergiant is nearly 1.5 billion miles across and, because of its size and position near the center of the galaxy, is probably around 13 billion years old, just a few hundred million years younger than the age of the Universe itself.

Even if you use light as a marker, the size of Universe remains unfathomably immense. Over the course of the Universe’s lifetime, a photon could have travelled 13.8 billion light-years, just 15% of the current estimate of the Universe’s diameter of 93 billion light-years. See also what are the physical limits of humanity?

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

posted by Jason Kottke   Oct 19, 2017

Eclipse 2017 Mouser

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)

Full Moons on Flickr

posted by Jason Kottke   Oct 13, 2017

Penelope Umbrico Moons

For a pair of projects, Penelope Umbrico collected hundreds of photos of full Moons from Flickr and arranged them into massive wall-sized collages.

Everyone’s Photos Any License, looks at a purportedly more rarified photographic practice: taking a clear photograph of the full moon requires expensive specialized photographic equipment. However, when I searched Flickr for ‘full moon’ I was surprised to find 1,146,034 nearly identical, technically proficient images, most with the ‘All Rights Reserved’ license. Seen individually any one of these images is impressive. Seen as a group, however, they seem to cancel each other out. Everyone’s Photos Any License seeks to address the shifts in meaning and value that occur when the individual subjective experience of witnessing and photographing is revealed as a collective practice, seen recontextualized in its entirety.

For one of the project, Umbrico requested permission to display “Rights Reserved” photos from 654 photographers in exchange for 1/654 of the profit from any potential sale. Many of them were not into that arrangement, so she substituted images with Creative Commons licences instead.

See also Umbrico’s Sunset Portraits, Suns from Sunsets from Flickr, and TVs from Craigslist. (via austin kleon)

The Astronomy Photographer of the Year for 2017

posted by Jason Kottke   Oct 04, 2017

Astronomy Photo 2017

Astronomy Photo 2017

Astronomy Photo 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.

Solar system artwork featuring the precise locations of the planets on the day of your birth

posted by Jason Kottke   Sep 19, 2017

Solar System Birthday Map

Spacetime Coordinates sells prints, metal mementos, and t-shirts that feature the planets of the solar system in the exact locations they were in on the date of your birth (or other significant date). For their new Kickstarter campaign, they’re offering color prints.

While not as pretty as these prints, you can check what the solar system looked like for any date here.

When I was a kid, I spent far too many hours mucking around in Lotus 1-2-3 trying to make a spreadsheet to calculate how often all the planets in the solar system would line up with each other (disregarding their differing planes, particularly Pluto’s).1 I could never get it working. Turns out that a precise alignment has probably never occurred, nor will it ever. But all the planets are “somewhat aligned” every 500 years or so. Neat! (via colossal)

  1. I spent many more hours making a spreadsheet of every single baseball card I owned and how much it was worth, updated by hand from Beckett’s price guide. Time well spent?

The intricate wave structure of Saturn’s rings

posted by Jason Kottke   Sep 07, 2017

Saturn Waves by Cassini

On one of its final passes of Saturn, the Cassini probe captured this image of a wave structure in Saturn’s rings known as the Janus 2:1 spiral density wave. The waves are generated by the motion of Janus, one of Saturn’s smaller moons.

This wave is remarkable because Janus, the moon that generates it, is in a strange orbital configuration. Janus and Epimetheus (see “Cruising Past Janus”) share practically the same orbit and trade places every four years. Every time one of those orbit swaps takes place, the ring at this location responds, spawning a new crest in the wave. The distance between any pair of crests corresponds to four years’ worth of the wave propagating downstream from the resonance, which means the wave seen here encodes many decades’ worth of the orbital history of Janus and Epimetheus. According to this interpretation, the part of the wave at the very upper-left of this image corresponds to the positions of Janus and Epimetheus around the time of the Voyager flybys in 1980 and 1981, which is the time at which Janus and Epimetheus were first proven to be two distinct objects (they were first observed in 1966).

The photograph is also an optical illusion of sorts. The rings appear to be getting farther away in the upper lefthand corner but the plane of the photograph is actually parallel to the plane of the rings…it’s just that the wavelength of the density wave gets shorter from right to left.

Update: Here are those density waves converted into sound waves. The first set sounds like an accelerating F1 car.

Newly processed photos of Jupiter taken by NASA’s Juno probe

posted by Jason Kottke   Aug 31, 2017

Jupiter Juno

Jupiter Juno

Jupiter Juno

Seán Doran shared some recently processed photos of Jupiter that he worked on with Gerald Eichstädt. The photos were taken by NASA’s Juno probe on a recent pass by the planet. These are like Impressionist paintings…you could spend hours staring at the whirls & whorls and never find your way out. There are more images of Jupiter in Doran’s Flickr album, including this high-resolution shot that you can download for printing.

Great 1970 eclipse stamp by the legendary Lance Wyman

posted by Jason Kottke   Aug 24, 2017

Lance Wyman Eclipse Stamp

A Mexican postage stamp designed in honor of the 1970 total solar eclipse. It was designed by Lance Wyman, who also did the logo and graphics for the 1968 Olympics in Mexico City.

The best photos and videos of the 2017 solar eclipse

posted by Jason Kottke   Aug 23, 2017

2017 Eclipse Photos

2017 Eclipse Photos

2017 Eclipse Photos

2017 Eclipse Photos

2017 Eclipse Photos

2017 Eclipse Photos

2017 Eclipse Photos

Photo and video credits from the top: Nashville progression photo by Richard Sparkman. HDR photo with Moon detail by Dennis Sprinkle (this one blew my mind a little). Rock climber by Ted Hesser (the story behind the photo). Progression photo by Jasman Lion Mander. Photo from the Alaska Airlines flight by Tanya Harrison. Video of the eclipse shadow moving across the Earth from the NOAA’s DSCOVR satellite. Neon cowboy photo by Rick Armstrong. ISS transit photo and video by Joel Kowsky. Partial eclipse video by NASA’s SDO spacecraft. Partial eclipse video by the ESA’s Proba-2 satellite. Video of the eclipse shadow moving across the US by the NOAA’s GOES-16 weather satellite. Time lapse video from The Salt Lake Tribune. Amazing 4K close-up video by JunHo Oh, ByoungJun Jeong, and YoungSam Choi…check out those prominences!

More eclipse photos on Petapixel (and here), BBC, Bored Panda, The Verge, and the NY Times.

Update: I added the time lapse video from The Salt Lake Tribune. (via the kid should see this)

Update: Added the 4K close-up video.

What witnessing a total eclipse is like

posted by Jason Kottke   Aug 23, 2017

In an essay from 1982 about her seeing a total solar eclipse in Washington (recently republished in this collection), Pulitzer Prize winner Annie Dillard puts into words what I only attempted to express in my eclipse experience.

I had seen a partial eclipse in 1970. A partial eclipse is very interesting. It bears almost no relation to a total eclipse. Seeing a partial eclipse bears the same relation to seeing a total eclipse as kissing a man does to marrying him, or as flying in an airplane does to falling out of an airplane. Although the one experience precedes the other, it in no way prepares you for it.

I heard lots of disappointment with the eclipse among friends and on social media. It was neat — look, there’s a chunk out of the Sun — but they thought it would be darker or that the air would get colder. But none of that stuff really happens unless you’re really close to totality…and then it goes completely dark and your brain turns inside out. Twitter user @hwoodscotty said:

Probably the coolest thing I’ve ever seen. Totality is so much different than even 99%. 10/10 Would recommend.

And @omanreagan:

Standing on a mountaintop for totality was crossing into another dimension, suddenly finding ourselves on another world. Amazing. Sparkling ring, sun fire ghostly streaming, darkest circle. I understand now why people chase the eclipse. Totality is unlike anything. Entire landscape shifted, valleys, hills, mountains painted in nightcolour and cold. Sparkling planets came out in a midnight sky.

But back to Dillard’s piece…this part, about the shadow rushing towards them, sounds amazing:

I have said that I heard screams. (I have since read that screaming, with hysteria, is a common reaction even to expected total eclipses.) People on all the hillsides, including, I think, myself, screamed when the black body of the moon detached from the sky and rolled over the sun. But something else was happening at that same instant, and it was this, I believe, which made us scream.

The second before the sun went out we saw a wall of dark shadow come speeding at us. We no sooner saw it than it was upon us, like thunder. It roared up the valley. It slammed our hill and knocked us out. It was the monstrous swift shadow cone of the moon. I have since read that this wave of shadow moves 1,800 miles an hour. Language can give no sense of this sort of speed — 1,800 miles an hour. It was 195 miles wide. No end was in sight — you saw only the edge. It rolled at you across the land at 1,800 miles an hour, hauling darkness like plague behind it. Seeing it, and knowing it was coming straight for you, was like feeling a slug of anesthetic shoot up your arm. If you think very fast, you may have time to think, “Soon it will hit my brain.” You can feel the deadness race up your arm; you can feel the appalling, inhuman speed of your own blood. We saw the wall of shadow coming, and screamed before it hit.

Next time, and there will definitely be a next time, I’m hoping to get up high somewhere so I can see the shadow and more of the 360-degree sunset. BRB, pricing plane tickets to Argentina

Update: Before the 2017 eclipse, Vox talked to some eclipse chasers about what it’s like to witness a total solar eclipse.

Joss Fong, who produced the video, shared the following on Twitter:

now that i’ve recovered from the drive, i can say that a lot of what these eclipse chasers told me makes sense now. agree completely that it’s something you have to see for yourself. what was different for me though is …. i got pretty sad. there’s a fine line between awe and grief. maybe in a different year it would have gone the other way, but tbh every exceptionally beautiful sunset makes me a tiny bit sad too. but this was sunset sadness times a thousand. absolutely punched by the impermanence. i hope i see it again and i hope you can see it too.

Update: From XKCD:

XKCD eclipse

I watched from a beautiful nature reserve in central Missouri, and it was — without exaggeration — the coolest thing I’ve ever seen.

My 2017 total solar eclipse trip

posted by Jason Kottke   Aug 22, 2017

Eclipse 2017 Mouser

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:

Eclipse 2017 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).

A simulated “play-by-play” of a total eclipse

posted by Jason Kottke   Aug 20, 2017

This video from the Weather Channel is pretty neat and useful: a play-by-play of what to expect during the eclipse, from being able to see Venus in broad daylight to animals possibly acting weird to the 360-degree “sunset” that happens about 2 minutes before totality.

Viewing a total solar eclipse from an airplane

posted by Jason Kottke   Aug 18, 2017

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

posted by Jason Kottke   Aug 18, 2017

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.

Saros 145

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.

Infographic of the fascinating timeline of the far future

posted by Jason Kottke   Aug 17, 2017

Timeline of The Far Future

Timeline of the far future is one of my favorite pages on Wikipedia. It details what might happen to humanity, human artifacts, the Earth, the solar system, and the Universe from 10,000 years from now until long past the heat death of the Universe. Information is Beautiful has made a lovely infographic of the timeline.

Reading through the timeline is a glorious way to spend time…here are a few favorites I noticed this time around as well as some from my first post.

August 20, 10,663: “A simultaneous total solar eclipse and transit of Mercury.”

20,000 years: “The Chernobyl Exclusion Zone, the 1,000 sq mi area of Ukraine and Belarus left deserted by the 1986 Chernobyl disaster, becomes safe for human life.”

296,000 years: “Voyager 2 passes within 4.3 light-years of Sirius, the brightest star in the night sky.”

1 million years: “Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.”

1 million years: “On the Moon, Neil Armstrong’s ‘one small step’ footprint at Tranquility Base will erode by this time, along with those left by all twelve Apollo moonwalkers, due to the accumulated effects of space weathering.”

15.7 million: “Half-life of iodine-129, the most durable long-lived fission product in uranium-derived nuclear waste.”

100 million years: “Future archaeologists should be able to identify an ‘Urban Stratum’ of fossilized great coastal cities, mostly through the remains of underground infrastructure such as building foundations and utility tunnels.”

1 billion years: “Estimated lifespan of the two Voyager Golden Records, before the information stored on them is rendered unrecoverable.”

4 billion years: “Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed ‘Milkomeda’.”

7.59 billion years: The Earth and Moon are very likely destroyed by falling into the Sun, just before the Sun reaches the tip of its red giant phase and its maximum radius of 256 times the present-day value. Before the final collision, the Moon possibly spirals below Earth’s Roche limit, breaking into a ring of debris, most of which falls to the Earth’s surface.

100 billion years: “The Universe’s expansion causes all galaxies beyond the Milky Way’s Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.”

A tour of our solar system’s eclipses

posted by Jason Kottke   Aug 16, 2017

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?

posted by Jason Kottke   Jul 20, 2017

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

posted by Jason Kottke   Jul 12, 2017

Solar Eclipse Illo

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:

Solar Eclipse Leaves

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.

Decoding the geometry, geology, and astronomy of Stonehenge

posted by Jason Kottke   Jun 28, 2017

Vox’s Joss Fong assembles a scale model of Stonehenge and explains some of the ancient monument’s geometry, the geology of the stone it’s built from, and the its possible astronomical significance.

Stonehenge is a popular destination for summer solstice celebrations because the 5,000-year-old monument points toward the summer solstice sunrise on the horizon. However, it also points to the winter solstice sunset in the opposite direction and there’s good reason to believe that this may have been the more important alignment for the Neolithic people who built Stonehenge. We investigate by constructing a tiny model of the Stonehenge monument.

NASA’s super accurate map of the 2017 eclipse

posted by Jason Kottke   Jun 14, 2017

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.

You can download maps of your area from NASA’s official eclipse website…I will be studying the Nebraska map closely.

Nebraska Eclipse Map

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.

Vivid new images and flyby videos of Jupiter

posted by Jason Kottke   May 30, 2017

Jupiter South Pole Juno

NASA’s Juno spacecraft is currently orbiting around Jupiter and taking some of the best photos and scientific measurements we’ve seen of the solar system’s largest planet. The photo above is of Jupiter’s south pole, gathering point for massive cyclones.

Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.

“We are excited to share these early discoveries, which help us better understand what makes Jupiter so fascinating,” said Diane Brown, Juno program executive at NASA Headquarters in Washington. “It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.”

Using data and photos from Juno, Gerald Eichstädt and Seán Doran have created these videos that approximate what it might look like flying by Jupiter in a spacecraft.

Wonderful.

What will the night sky look like in 5 million years?

posted by Jason Kottke   Apr 13, 2017

Based on the motions of the 2 million stars observed by ESA’s Gaia mission over the past two years, scientists created this simulated animation of how the view of the Milky Way in the night sky will evolve over the next 5 million years.

The shape of the Orion constellation can be spotted towards the right edge of the frame, just below the Galactic Plane, at the beginning of the video. As the sequence proceeds, the familiar shape of this constellation (and others) evolves into a new pattern. Two stellar clusters — groups of stars that were born together and consequently move together — can be seen towards the left edge of the frame: these are the alpha Persei (Per OB3) and Pleiades open clusters.

Stars seem to move with a wide range of velocities in this video, with stars in the Galactic Plane moving quite slow and faster ones appearing over the entire frame. This is a perspective effect: most of the stars we see in the plane are much farther from us, and thus seem to be moving slower than the nearby stars, which are visible across the entire sky.

Well, how’s that for some perspective? (via blastr)

The Orion Nebula, our friendly neighborhood star factory

posted by Jason Kottke   Apr 03, 2017

Orion Nebula

Rolf Olsen recently took this amazing photo of the Orion Nebula using a home-built telescope.

The Orion Nebula is one of the most studied objects in the sky and also has a significant place in the history of astrophotography. In 1880 it was the first ever nebula to be photographed; Henry Draper used the newly invented dry plate process to acquire a 51-minute exposure of the nebula with an 11 inch telescope. Subsequently, in 1883, amateur astronomer Andrew Ainslie Common recorded several exposures up to 60 minutes long with a much larger 36-inch telescope, and showed for the first time that photography could reveal stars and details fainter than those visible to the human eye.

Thanks to Phil Plait for the link…he’s got much more to say about the image and the nebula here.

Also called M42 (the 42nd object in a catalog kept by comet hunter Charles Messier in the late 18th century), it is a sprawling star factory, a gas cloud where stars are born. It’s a couple of dozen light-years across, and sits well over a thousand light-years from Earth. That’s 10,000 trillion kilometers, and you can see it with your naked eye! It’s so bright because of a handful of extremely massive hot stars sit in its center. They blast out ultraviolet light that energizes the gas in the nebula, causing it to glow.

It’s actually a small section of a much larger dark cloud, what’s called a molecular cloud, that we cannot see directly. Stars were born near the edge of that cloud, not too deeply inside it, and when they switched on their fierce light and stellar winds blew a hole in the cloud, popping it like a bubble. The Orion Nebula is a cavity in the side of that cloud, carved by the newborn stars.

A full rotation of the Moon

posted by Jason Kottke   Mar 31, 2017

All but a few humans have seen no more than half of the Moon with their own eyes. For the rest of us stuck on Earth, we only get to see the side that always faces the Earth because the Earth & Moon are tidally locked; the Moon’s rotation about its axis and its orbit around the Earth take the same amount of time. But NASA’s LRO probe has taken high-resolution photos of all but 2% of the Moon’s surface, which have been stitched together into this video of the Moon’s full 360-degree rotation.

A fictional flight above real Mars

posted by Jason Kottke   Mar 15, 2017

Using real images of Mars taken by the HiRISE camera on the Mars Reconnaissance Orbiter, Jan Fröjdman created a 3D-rendered flyover of several areas of the planet’s surface.

In this film I have chosen some locations and processed the images into panning video clips. There is a feeling that you are flying above Mars looking down watching interesting locations on the planet. And there are really great places on Mars! I would love to see images taken by a landscape photographer on Mars, especially from the polar regions. But I’m afraid I won’t see that kind of images during my lifetime.

It has really been time-consuming making these panning clips. In my 3D-process I have manually hand-picked reference points on the anaglyph image pairs. For this film I have chosen more than 33.000 reference points! It took me 3 months of calendar time working with the project every now and then.

Watch this in the highest def you can muster…gorgeous.

The Goddesses of Venus

posted by Jason Kottke   Mar 08, 2017

Goddesses Of Venus Map

Last year, Eleanor Lutz made a medieval-style map of Mars. As a follow-up, she’s made a topographical map of Venus. The features on Venus are named for female mythological figures & notable women and Lutz provides a small biography for each one on the map. Among those featured on the map are:

Anne Frank
Selu (Cherokee Corn Goddess)
Kali (Hindu Goddess, Mother of Death)
Virginia Woolf
Sedna (Eskimo Whose Fingers Became Seals and Whales)
Ubastet (Egyptian Cat Goddess)
Beatrix Potter
Edith Piaf

Here are the full lists of the craters, mountains, and coronae on Venus.

An appreciation of the Hubble’s Deep Field images

posted by Jason Kottke   Mar 03, 2017

More than 20 years ago, the Hubble Space Telescope took a photo of a patch of seemingly dark sky and, lo, it was filled with hundreds and hundreds of galaxies.

Hubble Ultra Deep Field

About ten years after that, they looked even deeper into the night sky and observed thousands of galaxies, each containing hundreds of billions of stars. The video above is an appreciation of these Deep Field images and what they taught us about the Universe.

In 1995, scientists pointed the Hubble Telescope at an area of the sky near the Big Dipper. The location was apparently empty, and the whole endeavour was risky — what, if anything, was going to show up? But what came back was nothing short of spectacular: an image of over 1,500 galaxies glimmering in a tiny sliver of the universe. Alex Hofeldt helps us understand the scale of this image.

NASA has found 7 Earth-like planets orbiting a single nearby star

posted by Jason Kottke   Feb 22, 2017

Trappist 1

Today NASA announced the discovery of seven planets “that could harbor life” around a dwarf star called Trappist-1.

The planets orbit a dwarf star named Trappist-1, about 40 light years, or about 235 trillion miles, from Earth. That is quite close, and by happy accident, the orientation of the orbits of the seven planets allows them to be studied in great detail.

One or more of the exoplanets - planets around stars other than the sun - in this new system could be at the right temperature to be awash in oceans of water, astronomers said, based on the distance of the planets from the dwarf star.

“This is the first time so many planets of this kind are found around the same star,” said Michael Gillon, an astronomer at the University of Liege in Belgium and the leader of an international team that has been observing Trappist-1.

Here’s the paper published in Nature.