kottke.org posts about space
The James Webb Space Telescope is designed to be positioned near one of the five Lagrange Points in the Sun/Earth system, special areas of gravitational equilibrium that keep objects stationary relative to both the Earth and the Sun. Here's how Lagrange Points work and why they are so useful for spacecraft like the Webb.
See also What Makes Lagrange Points Special Locations In Space.
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Space is mostly just what it says on the tin: empty space. The solar system is no exception; it's a massive volume occupied by little more than the Sun's mass — the mass of all the planets, moons, comets, asteroids, space dust, and stray electrons are just a bit more than a rounding error. But oh what mass it is when you get up close to it.
The NASA space probe Cassini, on its seven-year journey to Saturn, cozied up to Jupiter in December 2000 and captured a succession of images of Io and Europa passing over the Great Red Spot during the moons' orbit of the gas giant planet. Kevin Gill turned those images into the incredible video embedded above. That we have such crisp, smooth video of two small moons orbiting a planet some 444 million miles away from Earth is something of a miracle — it looks totally rendered. Also in the video is footage of Titan orbiting Saturn — that horizontal line bisecting the frame is Saturn's rings, edge-on.
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The James Webb Space Telescope is still winging its way to its permanent home at the L2 point1 about 930,000 miles from Earth — it's due to arrive in about 4 days. It's a massive and fascinating project and for his YouTube series Smarter Every Day, Destin Sandlin talked to Nobel laureate John Mather, the senior project scientist for the JWST, about how the telescope works.
Also worth a watch is Real Engineering's The Insane Engineering of James Webb Telescope:
It really is a marvel of modern science & engineering — I can't wait to see what the telescope sees once it's fully operational.
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Astronaut Scott Kelly arranged to have a gorilla suit sent up to him during his year spent on the International Space Station. One day, near the end of the mission in 2016, he put it on, stowed away in a large storage container, and then escaped and went on a "rampage".
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Charles and Ray Eames' 1977 short film Powers of Ten is one of the best bits of science communication ever created...and a personal favorite of mine. Here's a description of the original film:
Powers of Ten takes us on an adventure in magnitudes. Starting at a picnic by the lakeside in Chicago, this famous film transports us to the outer edges of the universe. Every ten seconds we view the starting point from ten times farther out until our own galaxy is visible only a s a speck of light among many others. Returning to Earth with breathtaking speed, we move inward — into the hand of the sleeping picnicker — with ten times more magnification every ten seconds. Our journey ends inside a proton of a carbon atom within a DNA molecule in a white blood cell.
As an homage, the BBC and particle physicist Brian Cox have created an updated version that reflects what we've learned about the universe in the 45 years since Powers of Ten was made. The new video zooms out to the limits of our current observational powers, to about 100 billion light years away, 1000X wider than in the original. (I wish they would have done the zoom in part of the video too, but maybe next year!)
And if you'd like to explore the scales of the universe for yourself, check out the Universe in a Nutshell app from Tim Urban and Kurzgesagt — you can zoom in and out as far as you want and interact with and learn about objects along the way.
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Using a composite of 25 different shots done over a period of 12 minutes in his backyard, amateur astrophotographer Andrew McCarthy created this stunning image of Comet Leonard. From PetaPixel:
Processing comet images is a challenge because even in the span of 12 minutes, the comet drifts across the frame relative to the background stars," McCarthy tells PetaPixel. "Due to the comet's motion, it has to be stacked differently. I tell the software to stack the images based on the comet position and star positions separately, which is then combined together to produce an image with the comet and stars both sharp.
See also this image of Leonard and McCarthy's colorful photo of a full moon.
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Inspired by the second book in Liu Cixin's excellent Three-Body Problem trilogy, Kurzgesagt made a video about the Dark Forest solution to the Fermi paradox.
Confronted with the seemingly empty universe, humanity faces a dilemma. We desperately want to know if we are alone in the Milky Way. We want to call out and reveal ourselves to anyone watching but that could be the last thing we ever do. Because maybe the universe is not empty. Maybe it's full of civilizations but they are hiding from each other. Maybe the civilizations that attracted attention in the past were wiped away by invisible arrows. This is the Dark Forest solution to the Fermi paradox.
I have The Dark Forest on the Kindle, so I looked up how this is explained in the book (spoilers, obvs):
"The universe is a dark forest. Every civilization is an armed hunter stalking through the trees like a ghost, gently pushing aside branches that block the path and trying to tread without sound. Even breathing is done with care. The hunter has to be careful, because everywhere in the forest are stealthy hunters like him. If he finds other life-another hunter, an angel or a demon, a delicate infant or a tottering old man, a fairy or a demigod-there's only one thing he can do: open fire and eliminate them. In this forest, hell is other people. An eternal threat that any life that exposes its own existence will be swiftly wiped out. This is the picture of cosmic civilization. It's the explanation for the Fermi Paradox."
Shi Qiang lit another cigarette, if only to have a bit of light.
"But in this dark forest, there's a stupid child called humanity, who has built a bonfire and is standing beside it shouting, 'Here I am! Here I am!'" Luo Ji said.
"Has anyone heard it?"
"That's guaranteed. But those shouts alone can't be used to determine the child's location. Humanity has not yet transmitted information about the exact position of Earth and the Solar System into the universe. From the information that has been sent out, all that can be learned is the distance between Earth and Trisolaris, and their general heading in the Milky Way. The precise location of the two worlds is still a mystery. Since we're located in the wilderness of the periphery of the galaxy, we're a little safer."
That's the basic idea, but there's more to it...you should watch the video or, even better, read the series — I've read the entire trilogy twice and this makes me want to read it again! (I loved the Drive Easter egg towards the end of the video. Well played.)
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In this entertaining, informative, and charmingly goofy video, Dr. Kevin Hainline tells us all about the James Webb Space Telescope. The JWST is a bigger and better version of the Hubble Space Telescope and will allow scientists to peer deeper into the universe and farther back in time than ever before.
Listen, science is hard! Engineering is hard! It's difficult to figure out how to build an incredibly sensitive infrared detector that you have to cram together on the back of a giant, foldable, gold covered mirror, sitting on a delicate, tennis-court-sized parasol, that can survive a rocket launch! It's hard stuff!
And hundreds and hundreds of people around the world have been working on it together. JWST is the single most complicated science project human beings have ever attempted. But it's been worth it. Because we want to discover the earliest galaxies in the universe, and clouds on other planets, and baby star-forming regions, and debris disks around stars, and weird dwarf galaxies, and supermassive black holes!
It's been in development for almost thirty years and everyone is really ready for it! The James Webb Space Telescope is about to change astronomy. Get ready for discovery!
I am ready and excited! The JWST is currently set to launch no earlier than Dec 24, 2021. You can follow the progress of the launch here.
See also Looking back in time with the James Webb Space Telescope (60 Minutes) and 29 Days on the Edge. Oh and scientists have been working on this project for 20 years and are (understandably) really nervous about what happens with the launch.
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For the first time in human history, a spacecraft has flown through the Sun's corona to collect data and capture samples (and, crucially, exited safely).
During the flyby, Parker Solar Probe passed into and out of the corona several times. This is proved what some had predicted — that the Alfvén critical surface isn't shaped like a smooth ball. Rather, it has spikes and valleys that wrinkle the surface. Discovering where these protrusions line up with solar activity coming from the surface can help scientists learn how events on the Sun affect the atmosphere and solar wind.
Six panels of images taken from inside a coronal streamer. They appear grayish with white streaks showing particles in the solar wind.
At one point, as Parker Solar Probe dipped to just beneath 15 solar radii (around 6.5 million miles) from the Sun's surface, it transited a feature in the corona called a pseudostreamer. Pseudostreamers are massive structures that rise above the Sun's surface and can be seen from Earth during solar eclipses.
Passing through the pseudostreamer was like flying into the eye of a storm. Inside the pseudostreamer, the conditions quieted, particles slowed, and number of switchbacks dropped — a dramatic change from the busy barrage of particles the spacecraft usually encounters in the solar wind.
For the first time, the spacecraft found itself in a region where the magnetic fields were strong enough to dominate the movement of particles there. These conditions were the definitive proof the spacecraft had passed the Alfvén critical surface and entered the solar atmosphere where magnetic fields shape the movement of everything in the region.
The first passage through the corona, which lasted only a few hours, is one of many planned for the mission. Parker will continue to spiral closer to the Sun, eventually reaching as close as 8.86 solar radii (3.83 million miles) from the surface. Upcoming flybys, the next of which is happening in January 2022, will likely bring Parker Solar Probe through the corona again.
The video above provides a great overview of the origins, objectives, and motivations for the mission.
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Seán Doran took 78,846 frames of data compiled by the Solar Dynamics Observatory over the course of a month and made this absolutely fantastic time lapse of the Sun slowly rotating and burning and flaring. Put this on the biggest, high-resolution screen you can and pretend you're in the solar observation room of the Icarus II in Sunshine.
See also A Decade of Sun and Gorgeous Time Lapse of the Sun. (via colossal)
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Eight hours of ambient chillout music over images pulled from NASA's photographic archive of nebulas, galaxies, planets, and other celestial objects? Sure, I'm in.
See also Hours and Hours of Relaxing & Meditative Videos.
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Roland Miller has been documenting space exploration for more than 30 years and his latest book, which he's funding via Kickstarter, is a photo documentation of the final years of NASA's Space Shuttle program.
I started documenting the Space Shuttle program when I was teaching photography at a college near the Kennedy Space Center. In 2008, I began a concentrated effort to document the final years of the program. Orbital Planes is the result of that photography work. My hope is that Orbital Planes will give the reader their own personal view of the Space Shuttle and the technology and facilities that helped it fly.
You might remember Miller from his collaboration with Italian astronaut Paolo Nespoli photographing the ISS. (via colossal)
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For the last nine months, NASA's Perseverance rover has been rolling around on Mars taking photos and doing science. It's also been recording audio of its environment with a pair of microphones and in this video, a pair of NASA scientists share some of those recordings and what we might learn about Mars from them.
This is one of my absolute favorite sounds. This is the sound of a helicopter flying on Mars. We used this sound to actually understand the propagation of sound in general through the Martian atmosphere, and it turns out that we were totally wrong with our models. The Martian atmosphere can propagate sound a lot further than we thought it could.
And surprisingly for me, that's my friend Nina in the video! (We eclipse-chased together in 2017.) I knew she was working on the rovers but didn't know she was going to pop up in this video I found on Twitter this morning. Fun!
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Last week, William Shatner finally got a chance to boldly go where he hadn't actually been before: into space. And upon returning from the 11-minute flight, the 90-year-old TV spaceship captain had come down with more than a touch of the Overview Effect. From the transcript of his post-flight remarks:
If.... Everybody in the world needs to do this...
Everybody in the world needs to see the..." (begins to cry) "...It was unbelievable, unbelievable. I mean, you know the little things... weightlessness... to see the blue color just.. go WHIP by!!! And now you're staring into blackness. That's the thing... the covering of blue... this sheet, this blanket, this comforter of blue that we have around us. We think, 'Oh, that's blue the sky!'
And then suddenly you shoot up through it all of the sudden... as if you whip off the sheet off you when you are asleep and you're looking into blackness. Into BLACK UGLINESS... And you look down and there's the blue down there... and the black up there and it's... it's just... there is Mother Earth... and comfort... and there is ....is there death? I don't know! Is that death? Is that the way death is?? WOOP, and it's gone! Jesus...
It was so moving to me... this experience ...it's something unbelievable. You see it... yeah, you know... weightlessness... my stomach went up and I thought, 'God, this is so weird...' but not as weird as the covering of blue... this is what I never expected. Oh, it's one thing to say, 'Oh... the sky and the thing and the... gradual...' It's all true... but what isn't true... what is unknown until you do it is... is this pillow.. There's this soft blue... look at the the beauty of that color! And it's so THIN! And you're through it in an instant...
He continued:
I don't know, I can't even begin to express what I ...what I would love to do is to communicate as much as possible ... the jeopardy... the the the moment you see how... The vulnerability of everything, it's so... small. This AIR which is keeping us alive is thinner than your skin! It's... it's a... it's a sliver! It's immeasurably small when you think in terms of the Universe! It's negligible! This air... Mars doesn't have it! No... nothing... I mean, this...
They should have sent a poet. Jokes aside, I'm sure that if I'd just returned from a flight into space, I'd would be equally flummoxed and unable to articulate what I'd just experienced. Hell, I couldn't even talk after seeing a solar eclipse.
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Marcella Giulia Pace photographed the Moon in 48 different hues and arranged them in a lovely spiral pattern.
I have collected some of my Full Moon shots taken over the past 10 years. I selected the shades of color with which the Moon was filmed in front of my lens and my eyes.
The atmosphere gives different colors to our satellite (scattering) based on its height with respect to the horizon, based on the presence of humidity or suspended dust. The shape of the Moon also changes: at the bottom of the horizon, refraction compresses the lunar disk at the poles and makes it look like an ellipse.
Prints of the image are available. (via @djacobs)
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The full moon was wonderful last night and Andrew McCarthy captured this colorful image of our nearest celestial companion. McCarthy explained where all those colors come from:
Back to this image, this was captured through a telescope and involved capturing thousands of frames to reveal the details. But what about the colors? The moon is gray, of course, but not *perfectly* gray. Some areas have a subtle blue tint, and others have a more orange tint. By teasing out those subtle colors, I can reveal the mineral composition of the moon! Blues denote titanium presence, while orange shows iron and feldspar present in the regolith. You can also see how impacts paint the surface with fresh color in the ejecta as they churn up material.
A print is available, but only for a very limited time (~6 more hours as of pub time).
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The Royal Museum Greenwich has announced the winners of the Astronomy Photographer of the Year for 2021. Zhong Wu won the galaxies category with a 360-degree view of the Milky Way (above, top), a mosaic which took two years to create — the northern hemisphere portion of the galaxy was photographed in China and the southern part in New Zealand. Jeffrey Lovelace's photo of the crescent moon over Death Valley sand dunes (above, bottom) took the prize in the skyscapes category.
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I love this post from the NYPL comparing astronomical drawings by E.L. Trouvelot done in the 1870s to contemporary NASA images.
Trouvelot was a French immigrant to the US in the 1800s, and his job was to create sketches of astronomical observations at Harvard College's observatory. Building off of this sketch work, Trouvelot decided to do large pastel drawings of "the celestial phenomena as they appear...through the great modern telescopes."
He made drawings of Saturn, Jupiter, aurora borealis, the Milky Way, and more. Here's his incredible drawing of sun spots compared to a recent image of the Sun's surface:


And his drawing of a solar eclipse compared to a recent image:


Check out the post for more examples of Trouvelot's work.
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Black holes are the largest single objects in the universe, many times larger than even the biggest stars, and have no upper limit to their size. But practically, how big is the biggest, heaviest black hole in the universe? (A: More massive than the entire Milky Way.)
The largest things in the universe are black holes. In contrast to things like planets or stars they have no physical size limit, and can literally grow endlessly. Although in reality specific things need to happen to create different kinds of black holes, from really tiny ones to the largest single things in the universe. So how do black holes grow and how large is the largest of them all?
Videos about space are where Kurzgesagt really shines. I've seen all their videos about black holes and related objects, and I always pick up something I never knew whenever a new one comes out. This time around, it was quasistars and the surprisingly small mass of supermassive black holes located at galactic centers compared to the galaxies themselves.
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In this collaboration between musician and filmmaker John Boswell (aka melodysheep) and the sound podcast Twenty Thousand Hertz, we get to listen to some of the actual and theoretical sounds of space, from what the Sun would sound like if space weren't a vacuum (we'd hear it as loud as a jackhammer on Earth) to the sound of the Universe just after the Big Bang to thunder in the thick atmosphere of Venus to dreamlike piano music on Mars.
Floating in the silent void of space are trillions of islands of sound, each with their own sonic flavor — some eerily familiar, some wildly different than Earth's. And even space itself was once brimming with sound.
This short film takes you on a journey back in time and to the edge of our solar system and beyond, to discover what other worlds of sound are lurking beyond Earth's atmosphere. You won't believe your ears :)
This is really well done, which isn't surprising considering Boswell did the excellent Timelapse of the Future video a few years back. The soundtrack to The Sounds of Space video is available on Bandcamp. (via aeon)
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After Neil Armstrong and Buzz Aldrin landed on the Moon 52 years ago today in the Lunar Module (aka Eagle), they rode the ascent stage of the LM back to rendezvous with Michael Collins in the Command Module (aka Columbia). After docking, Eagle was jettisoned and the three astronauts returned to Earth in Columbia. It was presumed that Eagle orbited the Moon until eventually crashing into the surface, but a recent analysis shows that the spacecraft may have entered a stable orbit and is still circling the Moon decades after the end of the mission, a priceless artifact of an historic achievement.
Most spacecraft in lunar orbit suffer from instability in their orbits due to the 'lumpy' nature of the lunar gravity which tends to cause the orbits to eventually get so elliptical that they hit the moon.
However, an amateur space fan wanted to narrow down the possible impact location and used orbit modelling software to propagate the orbit forwards in time until it hit the moon. He was surprised to find that it didn't hit the moon, and remained in a stable orbit for decades, this suggests that the Eagle may still be orbiting the moon over 5 decades after being left there.
The paper detailing the analysis suggests that if Eagle has survived, it should be detectable by radar.
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The galaxy is wild. Our solar system, with its surprising abundance of living creatures and nonstop radiation and asteroid showers, is a placid, private garden compared to the rest of it.
In particular, there are perhaps trillions of rogue planets (planetary bodies ranging from little rocky Earth-sized guys to super-Jupiter gas giants) in the Milky Way, including a surprisingly large fleet of the things right near the galactic core.
This is unusual, since the typical way we detect exoplanets is by marking their repeated procession across a star. But rogue planets, by definition, don't orbit stars. So the way astronomers find them is a little different, requiring use of gravitational microlensing.
Gizmodo breaks it down:
Data gathered by NASA's now-retired Kepler Space Telescope has revealed a small population of free-floating planets near the Galactic Bulge. The new finding raises hope that a pair of upcoming missions will result in further detections of unbound planets, which drift through space separated from their home stars....
It's impossible to know what the conditions are like on these presumed rogue exoplanets, but [astronomer Iain] McDonald said they could be "cold, icy wastelands," and, if similar in size to Earth, their surfaces would "closely resemble bodies in the outer Solar System, like Pluto."
The new paper suggests the presence of a large population of Earth-sized rogue planets in the Milky Way. It's becoming clear that free-floating planets are common. McDonald said his team is currently working to come up with a more precise estimate for how many of them might exist.
Did you catch that part about how McDonald's team made this discovery using a now-retired telescope? Yeah. Apparently the new telescope projects coming online are both more powerful and (in particular) better equipped to detect gravitational lensing effects, and therefore more likely to detect rogue planets in the future.
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Well, this is cool: a recently discovered minor planet estimated to be between 62 and 230 miles across is currently journeying through our solar system and sometime in 2031 will be almost as close to the Sun as Saturn.
And it turns out, astronomers are about to witness the closest pass of this incredible round trip. Currently, 2014 UN271 is about 22 Astronomical Units (AU) from the Sun (for reference, Earth is 1 AU from the Sun). That means it's already closer than Neptune, at 29.7 AU. And it's not stopping there — it's already traveled 7 AU in the last seven years, and at its closest in 2031, it's expected to pass within 10.9 AU of the Sun, almost reaching the orbit of Saturn.
Before then, it's expected to develop the characteristic coma and tail of a comet, as icy material on its surface vaporizes from the heat of the Sun. This close pass would give astronomers an unprecedented close look at Oort cloud objects.
C'mon NASA, let's a get a probe fired up and visit this very unusual object!
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To inspire folks to seek out their own galactic vistas, Capture the Atlas has chosen the best photos of the Milky Way for 2021. The top photo was taken by Daniel Thomas Gum in Australia and the bottom one by Larryn Rae in New Zealand. Check out the rest of the selections here.
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In the history of science, there are women who have made significant contributions to their field but haven't gotten the recognition that their male peers have. The field of astronomy & astrophysics in particular has had many female pioneers — Vera Rubin, Cecilia Payne-Gaposchkin, Annie Jump Cannon, Nancy Grace Roman, Maria Mitchell, Jocelyn Bell Burnell, Henrietta Swan Leavitt, Caroline Herschel, Williamina Fleming, and many others. Add to that list Hisako Koyama, a Japanese astronomer whose detailed sketches of the Sun over a 40-year period laid the foundation for a 400-year timeline of sunspot activity, which has aided researchers in studying solar cycles and magnetic fields.
Ms. Koyama was a most unusual woman of her time. As a scientist, she bridged the amateur and professional world. She preferred "doing" activities: observing, data recording, interacting with the public, and writing. No doubt many Japanese citizens benefited from personal interaction with her. The space and geophysics community continues to benefit from her regular and precise observations of the Sun. Although we know very little of her young personal life other than she was relatively well educated and had a father who supported her desire to view the skies by providing a telescope, we can see from snippets in Japanese amateur astronomy articles that she had a passion for observing, as revealed in her 1981 article: "I simply can't stop observing when thinking that one can never know when the nature will show us something unusual."
Here are a few of her sunspot sketches, the top two done using her home telescope and the bottom one using the much larger telescope at the National Museum of Nature and Science (that shows the largest sunspot of the 20th century):


(via the kid should see this)
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This is a photo of a tiny tiny snippet of the universe, taken by the Hubble Space Telescope. Every object you see in the photo is a staggeringly massive galaxy that contains hundreds of billions of stars along with all sort of other things.
Our own galaxy, the Milky Way, is well over one hundred thousand light years across. We only see a pitiful portion of it. Although it contains several hundred billion stars in its expanse, we can only see a fraction of a fraction of them.
And even that doesn't fully capture the essence of a galaxy, which also has planets, gas, dust, dark matter, and more. Galaxies are colossal objects, their true nature only becoming apparent to us a century ago.
I know I've posted photos like this before, but every time I see something like this, my mind boggles anew at the sheer scale and magnitude of it all and I just have to share it.
P.S. And Earth contains the only sentient life in the entire universe? Lol.
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Jon Larsen collects and photographs micrometeorites from all over the world, finding them even in urban areas mixed in among terrestrial dust and dirt.
The cosmos is a swirling soup of stardust. Every day, approximately 60 tons of dust from asteroids, comets, and other celestial bodies fall to the Earth. These tiny metallic, alien stones of various shapes, textures, and colors-known as micrometeorites-are some of the oldest pieces of matter in the solar system.
Even though micrometeorites blanket the Earth, scientists have generally only been able to discover them in remote places devoid of human presence, such as Antarctic ice, desolate deserts, and deep-sea sediments. Scientists began searching for micrometeorites in the 1960s, and they predominantly thought the extraterrestrial dust would be impossible to find in urban environments. The conventional wisdom held that densely populated areas had too much man-made sediment that camouflaged the tiny space particles.
But Jon Larsen, a Norwegian jazz musician and creator of Project Stardust, was able to show that it is possible to find micrometeorites in more populated areas. In a study published in January 2017 in the journal Geology, he and his colleagues catalogued more than 500 lustrous micrometeorites (and counting), all recovered from rooftops in urban areas.
Check out Larsen's Project Stardust for more photos and information on how to hunt for your own. (via the kid should see this)
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Astrophotography enthusiast Andrew McCarthy took a 140-megapixel photo of the Sun yesterday and, gosh, the Sun is just so cool to look at. I don't know if you can see it above, but there's a little something hidden in the photo, a transiting ISS:

The full-size image is available to McCarthy's supporters on Patreon.
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For his Earth Restored project, Toby Ord digitally remastered 50 photographs of the whole Earth taken by Apollo astronauts during their missions in the 60s and 70s.
The Apollo photographs are historic works of art. So in restoring them, I sought to bring out their own beauty. I refrained from recomposing the images by cropping, or trying to leave my own mark or interpretation. Perhaps in some cases this would make a more pleasing image, but it was not my aim.
And the Apollo photographs are also a scientific record of what our Earth looks like. In particular, what it would have looked like from the perspective of the astronaut taking the shot. So rather than pumping the saturation or adjusting the colours to what we think the Earth looks like, I wanted to allow us to learn from these photographs something about how it actually appears.
Many of these shots are new to me — the Apollo program and its scientific and cultural output continue to be revelatory 50 years later.
Update: Full resolution images are available when you click through on each photo. You may have to make your browser window wider to see the link. (thx, colin)
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