Justin Bartel
LightNews LightNews
banner
cephalopernicus.bsky.social
Justin Bartel
@cephalopernicus.bsky.social
100 followers 320 following 200 posts
#BetterKnowAnAsteroid has made it to the sky site, prepare for space rock news. Space wizard. Dog haver. Seasonal baker.
Posts Replies Media Videos
cephalopernicus.bsky.social
Happened to catch last night's chatter about #A11pl3Z, seemingly the third interstellar object found visiting the solar system, and added its trajectory into our planetarium software—I also uploaded it to a cloud server so that other users had immediate access. #BetterKnowAnAsteroid
Against a black background, the Sun appears as a small glowing orb in the distance near the center of the image. The orbits of the planets are drawn around it, with the orbits of inner rocky planets huddled close to the Sun, and the larger orbit of Jupiter extending across about half the width of the image. A bit of Saturn's orbit is visible at the top of the frame too. Cutting in from the lower left is a read line that extendds just inside the orbit of Jupiter, and is labeled "A11pl3Z". A fainter red line showing the object's future path extends across the solar system, cutting just inside the orbit of Mars and then back out, never to return.
July 2, 2025 at 3:05 PM
cephalopernicus.bsky.social
The value of fully embracing your niche interests:

Yesterday, the @vrubinobs.bsky.social released their 1st images, and bragged about the scope's capabilities, including the quick discovery of over 2,100 asteroids. They didn't rush to release the orbital info of these worlds... but I found them.
Screenshot of the Minor Planet Center website showing two recently released electronic circulars—announcements of new minor planet discoveries. Each circular has a unique number and are added to the website with the newest first. This screenshot is from the morning of June 24, 2025. The top circular is numbered MPEC 2025-M85 and dated June 24th. The line below gives the provisional designation of the asteroid described therein, in this case 2025 MN88. The next line of this screenshot is MPEC 2025-M84, the previous circular in sequence. The asteroid it announces is designated 2025 MO2. On a black background, the Sun appears in the bottom right, ringed by the orbits of the planets, seen in an oblique view slightly above the plane of the solar system. A faint cloud of dots marks the asteroid belt, between the orbits of Mars and Jupiter. In the top left corner of the image, a small rectangle appears with a few faint yellowish dots visible scattered within it. This is a huge image recently released by the Rubin Observatory, seen in its appropriate place in the sky. In a line running between the Earth and the Rubin image, a portion of the main asteroid belt looks brother. A few extra dots can also be picked out just inside and outside the belt. Together, these dots mark the 2,100 new asteroids discovered in the Rubin Observatory's first science quality deep field image.
June 25, 2025 at 12:53 AM
cephalopernicus.bsky.social
Sure, the images are great, but my takeaway from the @vrubinobs.bsky.social #RubinFirstLook is the 2,104 asteroid discoveries in just 10 hours of observations.

Almost instantly, Rubin Observatory has become the 17th most prolific asteroid discoverer ever (out of over 2,000). #BetterKnowAnAsteroid
A video of two spiral galaxies set against a mostly black background that's peppered with innumerable smaller and more distant galaxies in a variety of colors. Just right of center is a large spiral galaxy appearing in shades of white, yellow, and blue. Near the top left corner is a smaller, bluer spiral galaxy. Scattered across the image are multicolored lines of dots, red on one end, green in the middle, and blue on the other end. These are asteroids, captured in different locations as the telescope took multiple exposures through different filters. A close-up of an asteroid track in the Rubin Observatory First Look imagery. Innumerable galaxies are scattered across the black background. Near the center of this image, there are two red streaks just to the left of four green streaks, with a few blue steaks lined up on the right. All of these streaks are in a straight line. They show an asteroid's motion through the telescope's field of view across multiple observations taken through different filters.
June 23, 2025 at 3:25 PM
cephalopernicus.bsky.social
So, has everyone else already watched the new #asteroid documentary from NASA? And are we all ready for the Lucy flyby of Donaldjohanson on Sunday? #BetterKnowAnAsteroid

With apologies to Dr. Reddy, who's doing great work at my alma mater...
A version of the meme featuring a scene from The Simpsons in Bart's classroom, split into three panels vertically. In the top panel, several school children and their teacher are looking expectantly at the camera. You've got Milhouse, Martin, several other children—the gang's all there. The caption, "say the line, asteroid expert!" appears over this panel. In the second panel, Bart Simpson has been replaced with a screenshot from the new NASA documentary 'Planetary Defenders'. Dr. Vishnu Reddy appears with a large observatory telescope behind him. The caption reads, "the dinosaurs went extinct because they didn't have a space program." In the third panel, we return to The Simpsons classroom, with a wider overhead shot showing Bart near the center, sitting dejectedly, while everyone else surrounding him has their arms in the air and are cheering in celebration.
April 18, 2025 at 2:10 PM
cephalopernicus.bsky.social
It's the weekend, so the horrors of late-stage capitalism are slightly subdued. Not content with hyping astrological terms like "supermoon" and "blood moon", we're telling people that the peak minute of a "micromoon" matters. Imagine this journalistic effort being spent on something important
A USA Today headline reading "What time is the full moon tonight? See peak minute, cloud forecast for 'pink moon'" A portion of the article reading "Saturday night's full moon is special in more ways than one. Observers will witness both a micromoon and a pink moon at the same time Saturday night. The micromoon refers to a full moon that rises when the celestial body is the farthest from Earth, which NASA states is about a 251,000-mile distance. Space enthusiasts may notice the full moon appearing up to 14% smaller and 30 percent dimmer than a supermoon, according to the space agency."
April 12, 2025 at 3:31 PM
cephalopernicus.bsky.social
My #planetarium is ready for the upcoming #BetterKnowAnAsteroid holiday, April 20. The Lucy spacecraft will fly by a smallish main belt #asteroid named Donaldjohanson. For this #astroviz, I made full use of SPICE kernels to control the 3D model. Always happy to shine a light on #TeamAsteroid!
March 30, 2025 at 1:05 AM
cephalopernicus.bsky.social
Hera's #BetterKnowAnAsteroid test run at Mars is in the #planetarium and ready for tomorrow's shows
Picture taken in a planetarium with a mostly black background. In the top left, a simulation of the planet Mars is seen at a middle distance, with the orbits of its mind drawn around it. A spacecraft with gold foil on the side facing us and solar panels stretching out to the left and right is seen in front of Mars, simulating the recent flyby conducted by the ESA Hera mission. Centered and in the foreground of the scene are three images released by ESA. On the left is a colorized near infrared image with the small moon Deimos backdropped by the disk of Mars rendered in hues of blue. In the middle is a yellow-red-purple colored mid infrared image showing temperature differences—Deimos is bright yellow indicating higher temperatures than mostly orange, red, and purple Mars. Finally on the right is a colorized image from the framing camera meant to initiate what the human eye might see. Mars' cratered surface is orange and Deimos is dark gray.
March 13, 2025 at 10:07 PM
cephalopernicus.bsky.social
NASA's SPHEREx mission was also launched overnight and its initial orbit appeared in online catalogs today. This means I can put it in the #planetarium too. After these images were taken, I updated the model to improve the shadowing on the interior of the sunshade.
A scene of a spacecraft in orbit around the Earth. Most of the left half of the image is black, with a few distant stars; the Sun is also fairly prominent in the top left quadrant, appearing as a bright white spot. The right half of the image includes Earth in the background, with white clouds and blueish ocean, accentuated by a pinkish reflection of the water's surface. In the foreground is the SPHEREx spacecraft. On its right side, a bit of the spacecraft bus is visible—basically a white cylinder with a rectangular solar panel on the back side, facing the Sun. The spacecraft's most dominant feature is a large cone attached to the bus, appearing near the center of the image. It provides shade, and therefore cool temperatures, for the infrared telescope inside. It kind of looks like a satellite went to the vet and got a cone of shame though. A zoomed out version of the previous image. Most of the background is black with distant stars scattered about. The whitish Sun is in the top left quadrant, and it looks like a very bright star. The Earth fills the lower right quadrant, and we see mostly the nighttime side of the planet, with a few city lights. I think the most prominent landmass is Africa (it's "upside down" with south pointing up). A blue arc is traced up over the south pole of Earth, right along the day-night terminator, showing the synchronous polar orbit of SPHEREx.
March 13, 2025 at 1:16 AM
cephalopernicus.bsky.social
I also noticed that the MIT scientists working on the TESS mission posted their plan for the mission's 8th year of science operations. They'll be mixing things up, rotating the spacecraft for each sector, giving extra coverage to areas sparsely covered previously.

I also think it's a pretty pattern
This is a wide angle picture taken in a planetarium. The background is black, and the accent is filled with a series of alternating red, green, and blue rectangles, with each rectangle split into 16 smaller squares. These boxes represent the field of view of the detectors on the TESS spacecraft. Each different colored section is a "sector", a region the spacecraft will observe for a month or two at a time. The array of sectors in this image is the plan for the mission's 8th year, and it's a unique arrangement that the up looking a boy like a capital letter G rotated 90 degrees counterclockwise.
March 13, 2025 at 1:02 AM
cephalopernicus.bsky.social
I've seen other people get internet points for visualizing the newly discovered moons of Saturn in various ways, so here's my straight-ahead version. Behold, all 274 orbits, with the newest members of the family highlighted.

This was just one bit of spice in the last 24 hours for the #planetarium
This is a visualization of the orbits of all 274 known moons orbiting Saturn. Their orbits are traced in three dimensional space, and we're viewing the system from a slightly oblique angle above Saturday equator and a sufficient distance from Saturn that all of the previous are visible. The whole system is tipped slightly with the right side angled lower than the left. The orbits of the 146 moons known prior to yesterday's announcement are drawn in white, and the 128 just catalogued are drawn in blue Frankly, it's just a bird's nest of white and blue lines, but somehow it's also science.
March 13, 2025 at 12:54 AM
cephalopernicus.bsky.social
Ok here we go, peak #PuppyBowl #dataviz inconsistency! In Kiki's profile, 31% was drawn more than halfway down the number line and now 47% is clearly less than halfway down the line. I'll note that Sprinkle's profile is more or less internally consistent, but v. bad when compared to others. Shame!
Another Puppy Bowl DNA profile screenshot, like the others in this thread. The background of this one is ambiguous, but there's definitely some puppy bits back there. Here we're taking a look at Sprinkle's ancestry. Sprinkle is a white, fluffy did with floppy ears. They're mostly white but with some black accents on the left rear and a black line descending from the outside corner of their left eye, sort of looks like a tear. Our DNA breakdown is: 47% Australian shepherd, 12% great Pyrenees, and 6% American foxhound. Graphic design critique: the 12% slider is about twice as far down the line as the 6% slider, and the 47% slider is just shy of the hallway point down its line. This makes sense if you just read this post, but look back to the previous one, where a 31% marker was more than halfway down its line. Who is making these and why are they so bad?
February 9, 2025 at 8:51 PM
cephalopernicus.bsky.social
I caught another #PuppyBowl #dataviz, and I'm happy to say that some cracks are showing. First of all, we have 31% marked ~50% down the line, but maybe the axis is truncated. Label your axis! Still, at this scale, this isn't far off from 10-20-30 and the 18-31 gap seems a bit much compared to 10-18
Same basic sort of image as the previous post in this thread. The background this time is the green football-style turf. The feature of this graphic is Kiki, a very fluffy white dog, pictures at right. Our DNA breakdown this time is 31% Chihuahua, 18% cocker spaniel, and 10% Shetland sheepdog. At first glance, the 18% slider is roughly twice as far down its line as the 10% slider, and the 31% slider is maybe 3x times farther down the line... though if I'm splitting hairs, it looks to be too far down the line. Like we have essentially 10, 20, and 30, so at this scale the spacing should be pretty even, but the gap between 31 and 18 seems disproportionately large compared to the gap between 10 and 18. Without doing a check in outside suggested I can't be sure.
February 9, 2025 at 7:49 PM
cephalopernicus.bsky.social
One of my favorite bits to do on the old bird site was a careful analysis of the often shoddy #dataviz used during the #PuppyBowl. With those old records deleted, today's my first chance to revisit the topic here.

I think maybe this year's DNA breakdowns look pretty accurate?
59 >> 7 > 4 ✅
A screenshot from the television broadcast of the Puppy Bowl on Animal Planet. In the background, a striped referee's shirt is visible, but our focus is the foreground graphic. On the right is a picture of a young dog with a white body with black spots, and a largely black head with brown spots above his eyes and light stripes on the front of his floppy ears. The text to the left tells us these are DNA stats for the puppy named Bark Kent. Pretty good pun. Ok, so the breed mix is shown as 59% Shih Tzu, 7% dachshund, and 4% beagle. Short lines to the right of each breed have little sliders on them that move to the right at a distance relative to the percentages measured in the dog's DNA profile. Surprisingly (compared to previous years), the positions of the sliders looks about right based on the percentages written next to them.
February 9, 2025 at 7:33 PM
cephalopernicus.bsky.social
Screenshot of three text messages sent in quick secession: i ain't reading all that i'm happy for u tho or sorry that happened
February 3, 2025 at 5:58 AM
cephalopernicus.bsky.social
Wrapping up the talk, I offered a couple of planetary alignments that blow the current much-hyped arrangement out of the water. Mark these in your calendar
- Sept 8, 2040, all five visible planets will be low in the west after sunset, joined by a crescent Moon
- Nov 22, 2065, Venus transits Jupiter
The background, a post-sunset sky, fades from pale blue at the top to pale yellow at the bottom. I guess that's actually the foreground, because it's Earth's atmosphere. Beyond the atmosphere, all of the visible planets and a crescent Moon are visible and marked with circles and labels in the image. They could be imagined as being in two parallel diagonal line, from upper left to lower right. The top row, left to right, is the Moon, Saturn, and Jupiter; just below them, Mars, Venus and Mercury also appear. This is a real grouping of the planets that will occur on September 8, 2040. To view, you'll need a clear view of the western horizon after sunset. If you miss it on the 8th, the planets will maintain this fairly tight grouping plus/minus a couple days, but the Moon will only join them on the 8th. The planet Jupiter is shown in the center of a black background. A couple of Jupiter moons appear as tiny dots on either side of the planet. More impressively, the planet Venus is seen passing in front of Jupiter, skimming in front of the gas giant's south pole. This event will actually happen on November 22, 2065, but it will be a challenge to observe because the planets will be positioned quite close to the Sun in the morning sky during the transit. This sort of event hasn't happened since 1818! So if you have the means to observe, it's worth a shot, just be careful with telescopes pointed to close to the Sun!
January 26, 2025 at 11:38 PM
cephalopernicus.bsky.social
I was leaning into the idea of such alignments being pedestrian, so I also tossed in one example of a very out-of-the-ordinary exoplanet orbit. Behold, the curious case of TIC 241249530 b. It's a gas giant on a highly elliptical, retrograde daredevil orbit.
kpno.noirlab.edu/news/noirlab...
A whitish star is seen from a moderate distance, positioned just right of center. A red line is drawn through the central axis of the star, and a light purple arrow shows that the star is rotating roughly counterclockwise in this view. A planet's orbit is drawn around the star, approaching the star closely on the right and extending much farther from the star on the left. The orbit is brightest closest to the position of the planet and fades farther back along the planet's path. This shows us that planet is moving clockwise in this view, i.e., it's in a retrograde orbit. A few distant stars and the glowing band of the Milky Way are in the distance, otherwise the image is filled with the blackness of space.
January 26, 2025 at 11:27 PM
cephalopernicus.bsky.social
The answer: it's all but impossible. You might get two planets to transit the star as seen from Earth, but seven doesn't make much sense. No, the fact that we've found 3-, 4-, 5-, 6-, 7-, and even 8-planet transmitting systems means that it's completely normal for planets to form in a common plane.
Like the previous post, a reddish star is seen from a distance against a black background. Seven green planetary orbits are drawn around the star, but in this image they're all roughly aligned with one another in the same plane. With the more orderly planetary system, it's a bit easier to see other distant stars shine through the scene.
January 26, 2025 at 11:16 PM
cephalopernicus.bsky.social
In these transiting systems, we aren't seeing the planets directly, only detecting them indirectly.

Pop quiz! In a system of seven planets discovered via transits, what are the odds the orbits would be traced out like this:
A small reddish star is viewed from a distance against a black background. Multiple planetary orbits are drawn in green. The orbits are at all sorts of different angles, rather than lined up like the orbits of the planets in the solar system.
January 26, 2025 at 11:09 PM
cephalopernicus.bsky.social
And that's just the solar system. What else is going on out there? We know of thousands of exoplanets, planets orbiting other stars. Do we think that they bear any resemblance to our neighborhood? Each circle in these images represents an exoplanet; the concentric circles are multi-planet systems
A bright whitish star is just above center in this image. It's the Sun, seen from a large distance, but the focus of this image is all of the blue circles scattered across the blackness of space beyond the Sun. Each maps the location of a planet orbiting another star. Some are single circles, but many are groups of concentric circles. That means there are multiple planets orbiting the same star. Just to the right of center, a bunch of yellow circles are clustered together. They fill an area that could be imagined as a large square with small square-shaped cutouts at each corner. There's also a distinct pattern of lines devoid of yellow circles cutting across the large square. Each circle maps the location of a planet orbiting another star. Some are single circles, but many are groups of concentric circles. That means there are multiple planets orbiting the same star. In this image, only those exoplanets found during the Kepler telescope's prime mission are shown, so the arrangement of circles makes the shape of the camera's detector apparent. The mission used 21 CCD rafts, arranged in a regular pattern, like a 5x5 square, but with the corners empty.
January 26, 2025 at 11:04 PM
cephalopernicus.bsky.social
We back away a bit and consider the rest of Saturn's moons. Once again, the orbits get more elliptical and seem to be inclined randomly. Worse, many of these distant moons orbit Saturn backwards. Like the Kuiper belt, these orbits hint at a more complex story, likely one of capture and collision
A distant view of Saturn against a black background, though the planet is barely seen. More obviously, the image is filled with a visualization of the orbits of the 146 moons known to orbit the planet. Close to Saturn, appearing small in this image, are a few orbits that are aligned along the planet's equator, the more distant moons trace out large elliptical orbits that extend beyond the edges of the image. The orbits appear in two different colors. The inner moons and a few of the outer, inclined orbits are blue; these moons go around Saturn in the same direction, counterclockwise in the orientation of the image. The rest of the orbits, the vast majority of the outer moons, are drawn in red and they go around the planet in the opposite direction from the blue orbits.
January 26, 2025 at 10:47 PM
cephalopernicus.bsky.social
Back to our casual analysis of celestial mechanics and the stories a handful of orbits can tell.

Smash cut to Saturn. It has a bunch of moons. Some of the moons move on orbits nicely aligned with Saturn's rings and the planet's equator. The planet's largest moons form the bulk of this group.
The planet Saturn is seen from a moderate distance against a black background. Drawn around the planet in white are a couple dozen orbits followed by various moons. Some are embedded among the planet's rings, others are beyond the rings. A few are so large that they extend beyond the edges of this image. All of the moon orbits are seen to lie in the same plane as the rings, and are all aligned with each other. This is all reminiscent of the alignment of the major planets' orbits around the Sun.
January 26, 2025 at 10:39 PM
cephalopernicus.bsky.social
So an expectation has been set. Planets should appear in a straight line across our sky. The current appearance of the sky isn't terribly special, but it's still worth taking a look at.

But now we can start throwing curveballs. Planets line up, makes sense, so what's up with the Kuiper belt?
A distant view of the solar system, from slightly above the plane of the planets' orbits, set against a black background. The orbits of the eight major planets are traced around the Sun, but they're difficult to pick out. Outside the orbit of Neptune, thousands of little white dots and more than a hundred representative orbits have also been added. These are residents of the Kuiper belt, and their orbits tend to be more elliptical and inclined than the orbits of the planets. Many of these orbits are so elliptical that they extend beyond the edges of this image.
January 26, 2025 at 10:22 PM
cephalopernicus.bsky.social
The planets' orbits lie pretty close to the same plane, so they always move across the same part of our sky—the ecliptic. I'd be more impressed if the planets were scattered randomly across the sky! Their alignment is a relic of the solar system's formation. Planets formed from and remain in a disk.
A distant view of the solar system with the orbits of the planets highlighted, seen against a black background with a few stars. We're looking at the solar system 'edge-on', with all the of the major planets' orbits aligned with one another. If we were on the Earth instead, the orbits would still appear to be aligned, and indeed, that's why planets are always lined up across our sky. Just like the previous image, we're looking at the solar system from a distance, right along the plane of the planets' orbits. But this time, we've turned the clock back 4.6 billion years or so, and the newly-shining Sun is surrounded by a protoplanetary disk of dust and gas. The ingredients for making planets were in a disk when the solar system first formed, and it would take something pretty drastic to move them out of that plane. The background is an iridescent blue nebula with a large number of bright stars with bright diffraction spikes. The bottom third of the image is a shelf of glowing orange gas and dust. It's the JWST image of the Carina nebula.
January 26, 2025 at 10:09 PM
cephalopernicus.bsky.social
You know, the #PlanetParade, the #PlanetaryAlignment... the #OverHypedPlanets if you will. We quickly established that this collection of planets had been visible in the evening for weeks and would be visible for weeks to come. What gives?

This is a normal thing in our sky, and that's great!
A view of the portion of the solar system visible in the evening from the surface of the Earth in mid-January, seen from above the plane of the solar system. Against a black background with a few stars, the orbits of the planets are drawn around the Sun. Mercury and Earth are unabeled, but the positions of Venus, Mars, Jupiter, Saturn, Uranus, and Neptune are circled and labeled. All of the other planets except for Mercury are on the same side of the Earth right now, so they all appear in the sky together. In this graphic, there's also a red line drawn through the Sun. This marks its rotation axis, and a curved arrow helps illustrate that the planets orbit the Sun in the same direction it rotates.
January 26, 2025 at 9:57 PM
cephalopernicus.bsky.social
Can we stop making up dumb names for perfectly normal things the Moon does? At the very least, you shouldn't put an article in your publication's "Science" section that includes the phrase 'this isn't science'
A screenshot of a Newsweek headline stating "Black Moon: 13 US States Set to Experience Lunar Phenomenon" following by the published and updated dates of Nov 29 and Dec 2, respectively, in red. The header of the article indicates it was published in the Science section. A screenshot of the Newsweek article under the header, "What Is a Black Moon?" that says, "Though not a scientific term used by astronomers, a black moon has two possible definitions." The first sentence is at odds with the decision to publish the article as science.
December 2, 2024 at 7:25 PM