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kottke.org posts about Sun

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

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 Glasses

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. A 10-pack of glasses with cardboard frames is only $16. For something a little sturdier, go with glasses with plastic frames like this 3-pack for $15. If those choices aren’t available, there are dozens of options…find some in stock that ship soon. Note: If you have young kids, splurge for the plastic framed glasses…my testing indicates the cardboard ones don’t stay on smaller heads that 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. Better option for the casual photographer are adjustable lens filters or these cardboard lens covers: 70mm solar filter ($17) and 50mm solar filter ($13). Or 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 (like these or these) 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. The paper glasses I link to in this guide are safe…they have the ISO symbol and are made by American Paper Optics. (via @ebellm)

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

posted by Jason Kottke   Jul 11, 2017

Eclipse Map USA 2017

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

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.

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

posted by Jason Kottke   May 10, 2016

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

posted by Jason Kottke   Mar 24, 2016

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

posted by Jason Kottke   Mar 09, 2016

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

posted by Jason Kottke   Nov 24, 2015

Sunset

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

posted by Jason Kottke   Nov 03, 2015

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

posted by Jason Kottke   Sep 23, 2015

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

posted by Jason Kottke   Aug 19, 2015

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

posted by Jason Kottke   Mar 24, 2015

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

posted by Jason Kottke   Jan 26, 2015

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.

See also the view from Earth of different planets replacing the Moon and imagining Earth with Saturn’s rings.

Is it possible to extinguish the Sun with water?

posted by Jason Kottke   Dec 12, 2014

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

posted by Jason Kottke   Nov 10, 2014

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

posted by Jason Kottke   Aug 21, 2014

2017 Solar Eclipse Map

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

posted by Jason Kottke   Oct 25, 2013

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

posted by Jason Kottke   Jul 25, 2013

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

ISS Sun

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

ISS 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

posted by Jason Kottke   Jul 02, 2013

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.

A photon’s random walk

posted by Jason Kottke   Jun 27, 2013

The Sun is so dense at its core that the average photon created by the fusion process takes more than 40,000 years to escape to the surface. !!!

The center of the Sun is extremely dense, and a photon can only travel a tiny distance before running into another hydrogen nucleus. It gets absorbed by that nucleus and the re-emitted in a random direction. If that direction is back towards the center of the Sun, the photon has lost ground! It will get re-absorbed, and then re-emitted, over and over, trillions of times.

This is from 1997, so that figure might have been revised a bit (anyone have updated numbers?) but still, that’s incredible. (via hacker news)

Video portrait of the Sun

posted by Jason Kottke   Apr 26, 2013

In complete defiance of its parents, NASA’s Solar Dynamics Observatory has stared directly at the Sun for the past three years. Here’s a video of those three years made from still images taken by the SDO.

During the course of the video, the sun subtly increases and decreases in apparent size. This is because the distance between the SDO spacecraft and the sun varies over time. The image is, however, remarkably consistent and stable despite the fact that SDO orbits the Earth at 6,876 miles per hour and the Earth orbits the sun at 67,062 miles per hour.

The video notes say the animation uses two images per day…it would be nice to see the same animation with a higher frame rate. (via ★interesting)

The vortex view of planetary motion around the Sun

posted by Jason Kottke   Mar 01, 2013

Since the Sun moves relative to the other stars around it at about 45,000 miles/hr, if you change the frame of reference from the Sun to the surrounding stellar system, you get planetary motion that looks something like this:

I would take this video with a grain of salt though, especially when it says things like “the Sun is like a comet, dragging the planets in its wake”…the planets don’t lag behind the Sun. Better to think of the thing as a conceptual schematic: resembling reality but not really accurate. (via @pieratt)

Update: There’s a new version of the video that addresses some of the concerns raised about the first video:

(thx, john)

Update: Phil Plait from Bad Astronomy has posted a pretty thorough takedown of this video.

However, there’s a problem with it: It’s wrong. And not just superficially; it’s deeply wrong, based on a very wrong premise. While there are some useful visualizations in it, I caution people to take it with a galaxy-sized grain of salt.

Time lapse video of the transit of Venus

posted by Jason Kottke   Jun 06, 2012

Venus passed in front of the Sun yesterday for the last time until 2117. The transit took almost seven hours but this NASA video shows it in under a minute.

Solar eclipse…by Saturn

posted by Jason Kottke   Sep 12, 2011

The Cassini spacecraft caught this remarkable photo of Saturn eclipsing the Sun in 2006.

Saturn eclipse

Click through for the big image and the massive image. If you look close can see the Earth in the image, for reals!

Big orange ball

posted by Jason Kottke   Oct 29, 2010

What is this, do you think? Electron microscope photo of pollen? Infrared tennis ball? Mars? The inside of a baseball?

Hydrogen Sun

It’s actually a photo of the Sun taken at the H-alpha wavelength by an amateur astronomer.

Sun may affect radioactive decay rates

posted by Jason Kottke   Aug 25, 2010

During a search for a radioactive isotope-based random number generator, researchers discovered that radioactive decay rates, previously thought to be constant, appear to be influenced by the activity of the Sun.

On Dec 13, 2006, the sun itself provided a crucial clue, when a solar flare sent a stream of particles and radiation toward Earth. Purdue nuclear engineer Jere Jenkins, while measuring the decay rate of manganese-54, a short-lived isotope used in medical diagnostics, noticed that the rate dropped slightly during the flare, a decrease that started about a day and a half before the flare.

If this apparent relationship between flares and decay rates proves true, it could lead to a method of predicting solar flares prior to their occurrence, which could help prevent damage to satellites and electric grids, as well as save the lives of astronauts in space.

The decay-rate aberrations that Jenkins noticed occurred during the middle of the night in Indiana — meaning that something produced by the sun had traveled all the way through the Earth to reach Jenkins’ detectors. What could the flare send forth that could have such an effect?

Jenkins and Fischbach guessed that the culprits in this bit of decay-rate mischief were probably solar neutrinos, the almost massless particles famous for flying at nearly the speed of light through the physical world — humans, rocks, oceans or planets — with virtually no interaction with anything.

Maybe the science part of 2012 wasn’t so far-fetched after all. (No, not really.)

The solar superstorm of 1859

posted by Jason Kottke   Sep 04, 2009

A massive solar flare on September 1, 1859 “caused the most potent disruption of Earth’s ionosphere in recorded history”.

Within hours, telegraph wires in both the United States and Europe spontaneously shorted out, causing numerous fires, while the Northern Lights, solar-induced phenomena more closely associated with regions near Earth’s North Pole, were documented as far south as Rome, Havana and Hawaii, with similar effects at the South Pole.

(via the browser)

Our three Suns

posted by Jason Kottke   Aug 04, 2009

In early July, a photographer took a picture of what appears to be three Suns rising over Gdansk Bay in Poland.

Triple Sunrise

The photographer insists that the effect was not created by the camera and was visible to the naked eye. The early consensus in the forums is that the photo was taken through a double-paned window.

Photos of the Sun

posted by Jason Kottke   Oct 13, 2008

The Big Picture collects photos of the Sun. I’ve featured a number of these on kottke.org before but it never hurts to look often at the Sun.

Sunspots in Grand Central

posted by Jason Kottke   Jul 02, 2008

Observe sunspots by going to Grand Central Terminal?

The southern wall of the Grand Concourse, facing 42nd Street, has semicircular grills high up, with small curlicued spaces like those in a leafy tree. Many of those spaces act like the aperture of a pinhole camera, reflecting an image of the sun that, when it reaches the floor, will be 8 to 12 inches wide. The smaller grill spaces will produce dimmer but sharper solar images on your paper.

(via 92y blog)