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kellylepo.bsky.social
Kelly Lepo
@kellylepo.bsky.social
3.3K followers 350 following 1.2K posts
Astronomer | Science communicator | Adult Lisa Simpson
Freelance writer and editor. Former Education and Outreach Scientist at the Space Telescope Science Institute (@stsci.edu) supporting JWST.
Also on Mastodon: @[email protected]
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kellylepo.bsky.social
Working in astronomy outreach, you quickly learn that the average person knows way less than you think.

It's fine! You can live your whole life without knowing if the Sun is a star. I know because it is my job, most people don't have to.

But asking questions is the first step to learning more.
XKCD comic featuring two stick figures. Ponytail and Cueball are talking. Ponytail has her hand raised, palm up, towards Cueball. Ponytail: Silicate chemistry is second nature to us geochemists, so it's easy to forget that the average person probably only knows the formulas for olivine and one or two feldspars. Cueball: And quartz, of course. Ponytail: Of course. Caption below the panel: Even when they're trying to compensate for it, experts in anything wildly overestimate the average person's familiarity with their field.
January 18, 2026 at 11:21 PM
kellylepo.bsky.social
xkcd.com/2762/
The comic is a drawing of a star, with the diffraction spikes that usually happen when taking pictures with telescopes. An exoplanet orbits that star, and its trajectory crosses one of the spikes. At the intersection point, the onomatopoeia "SLICE" is written, and the trajectory splits in two. Not far after, two half-planets continue their course. Caption below panel: Bad news for exoplanets: it turns out those diffraction spikes are real.
January 14, 2026 at 3:35 AM
kellylepo.bsky.social
🤔 I think the dictionary is telling me I should get back into making sourdough.
Screenshot of a gif, text reads: Merriam-Webster Your 2026 Word yeasty
January 2, 2026 at 12:35 AM
kellylepo.bsky.social
First image: Wavelengths of light emitted by stars. We see millions of stars in the Milky Way, the Large and Small Magallanic Clouds, and some background galaxies.

Second image: Wavelengths of light emitted by polycyclic aromatic hydrocarbons (red), a type of cosmic dust, and hydrogen gas (blue).
An all-sky image, projected into an oval shape, centered on our Milky Way galaxy. A bright white band made of tiny white points of light runs horizontally across the image, this is the disk of the Milky Way. In the center of the image is the bulge of the Milky Way, seen as a fuzzy white sphere that extends slightly above and below the plane of the disk. Dust, seen as an irregular, translucent yellow-orange band, obscures some of the Milky Way's disk. Above and below the plane of the disk, there are numerous white dots, which are stars and background galaxies. To the bottom right, below the disk of the galaxy are the Milky Way's two tiny companion galaxies, the Small Magellanic Cloud and the Large Magellanic Cloud. The Small Magellanic Cloud appears a a fuzzy circular shape. The Large Magellanic Cloudis an oval shape, with a denser bar at its center. An all-sky image, projected into an oval shape, centered on our Milky Way galaxy. A bright white band runs horizontally across the image, this is the disk of the Milky Way. Red dusty gas fills the area above and below the disk, forming loops and patchy areas. Closer to the plane of the disk are blue, circular features, which are hot hydrogen gas. The features are smaller on the left side of the image and larger on the right side of the image. To the bottom right, below the disk of the galaxy, is the Large Magellanic Cloud, a companion galaxy to the Milky Way. It has a patchy oval shape.
December 19, 2025 at 7:43 PM
kellylepo.bsky.social
I had a blast walking with the @stsci.edu float for the Mayor’s Christmas Parade in Baltimore on Sunday.
December 15, 2025 at 7:19 PM
kellylepo.bsky.social
One of my favorite recent JWST images, Pismis 24, is now available as a free downloadable poster. Perfect for printing and decorating your walls.

It includes the image on the front and a description in both English and Spanish on the back. 🔭🧪

science.nasa.gov/asset/webb/p...
A vertically oriented poster with an image of Pismis 24 against a black background. A dark blue sky filled with white and yellow stars of different sizes covers about two thirds of the image. Across the bottom third of the scene are orange, mountain-like clouds with spire-like peaks that point toward a wispy white cloud which stretches horizontally across the scene. Dense clouds of a similar color are spread about the top right corner of the image. Along the bottom is a series of thin vertical bars ranging from purple at left to blue, green, yellow, orange, and red at right. Bars are separated slightly, with black in between. Bar colors are brightest at the bottom, fading up to black. Brightness varies from bar to bar, giving the array an undulating feel. At upper right is text that reads, “National Aeronautics and Space Administration” and NASA’s blue, white, and red meatball insignia. Title text appears at lower left that says, “James Webb Space Telescope: Pismis 24.”
December 12, 2025 at 9:49 PM
kellylepo.bsky.social
For about 25 years in their 190-year orbit, a pair of Wolf-Rayet stars in the Apep system get close enough that their winds collide. The colliding winds produce carbon-rich dust that surrounds the stars in a shell.

The shells then get blown outward by the winds.
2/
Four translucent dust shells expand away from three central stars that appear as a single pinpoint of light. Bright, arcing ridges partially outline the shells. The innermost shell is smallest, like the size of a thumbprint, and brightest. It is yellow and forms a backward lowercase e. A line at 3 o’clock swoops to the bottom-left in an arc that ends at 8 o’clock. A second line at 9 o’clock dips down to start, but then goes straight up, angling around the top. The second shell, about the size of a fist, is orange and has looser arcs. One appears from 4 to 7 o’clock. A brighter orange triangle appears from 10 to 12 o’clock. Its outer edges overlap, forming a rough circle. The third shell extends almost to the edges and is semi-translucent red, with similar arcs and a darker red line that also forms a faint triangle at top left. The widest shell is faintest and at the edges. A semi-transparent blue appears across the scene. A larger foreground star with spikes is at bottom left, and more distant stars and galaxies are strewn across the black expanse of space.
November 19, 2025 at 5:08 PM
kellylepo.bsky.social
Not quite as good as last night, but you could see faint aurora tonight from north of Baltimore, MD. 🔭🧪
A night scene showing the sky with faint red aurora. In the bottom quarter of the frame are some trees and a row of houses in the distance. Above is the night sky. Near the horizon is a faint red glow, the aurora, which almost looks like a thin, red cloud. Dotted across the sky are stars, which appear as points of light. A night scene showing the sky with faint red and green aurora. In the bottom quarter of the frame are some trees and a row of houses in the distance. Above is the night sky. Near the horizon is a faint green glow. Above this are two red patches to the left and right of center. They almost look like thin, red clouds. Dotted across the sky are stars, which appear as points of light.
November 13, 2025 at 3:52 AM
kellylepo.bsky.social
Time-lapse video of tonight's auroras from Maryland, about 4 minutes of real time.

I didn't think to bring a tripod, so this was the best I could do, propping my phone up on a stake holding a bush.
November 12, 2025 at 2:58 AM
kellylepo.bsky.social
Auroras from north of Baltimore, MD.

Taken with a long exposure on my phone. They are just barely visible to the naked eye. 🔭🧪
A night scene showing the sky lit up with red and green auroras. The lower half of the frame is filled with silhouetted trees. The upper half shows the night sky. Near the horizon, the sky glows green. Above this is a wide, faint red band with smaller red streaks. A few stars appear as points of white. A night scene showing the sky lit up with red and green auroras. The lower half of the frame is filled with silhouetted trees. Leaves from a tree are out of focus in the foreground near the left edge of the frame. The upper half shows the night sky. Near the horizon, the sky glows green. Above this is a wide, red band with smaller red streaks. Above this are thin, white clouds. A few stars appear as points of white.
November 12, 2025 at 2:51 AM
kellylepo.bsky.social
Is there a line that separates exoplanets with and without atmospheres — called the "cosmic shoreline"?

These stars are very active, sending out X-rays and flares, blasting the planets that orbit them. So it's not clear if we can extrapolate from the solar system. The program tests this hypothesis.
Five solar system objects and 9 exoplanets plotted on a graph titled, “Balance Between Starlight and Gravity: Which Rocky Planets Have an Atmosphere?” Vertical axis labeled, “Amount of High-Energy Light that Reaches the Planet,” with “more” at the top and “less” at the bottom. Horizontal axis labeled, “How Hard It Is for Atmosphere to Escape the Planet’s Gravity” with “needs less energy to escape” at left and “needs more energy to escape” at right. Background grades from black at top left to light blue at bottom right. Label pointing toward top left reads, “Atmosphere less likely.” Label pointing toward bottom right corner reads, “Atmosphere more likely." Key above graph shows that objects plotted as solid blue circles (Mars, Venus, Earth) have atmosphere. Solid gray circles (the Moon, Mercury) have no atmosphere. Open white circles (all nine exoplanets) are not yet determined. Solar system planets fall on the bottom left half of the graph. Exoplanets fall in the top right.
October 1, 2025 at 6:42 PM
kellylepo.bsky.social
We have found many rocky planets orbiting cool, red dwarf stars. But do these planets have atmospheres?

The Rocky Worlds Director’s Discretionary Time program has 500 hours of JWST time plus 250 HST orbits to help answer that question. 🔭🧪

science.nasa.gov/mission/webb...
Illustration showing a distant star, with two rocky planets in the foreground. The star is deep orange and appears to be very active, with dark and light spots and large flares. The planets appear to be the same distance from the star. The planet on the left is significantly smaller than the one on the right. Text beside the planet at left reads, “Smaller planet. Weaker gravity. Lower escape velocity. Atmosphere less likely.” Text for the planet at right reads, “Larger planet. Stronger gravity. Higher escape velocity. Atmosphere more likely.” The small planet at left is gray. The right quarter of the hemisphere is lit by the star. The boundary between the lit and dark sides is sharp. The larger planet at right is blueish white with swirling clouds. The left quarter is lit by the star. The boundary between the lit and dark sides is fuzzy. Illustration showing two star-planet systems, with stars in the background and planets in the foreground. The planets are the same size, but the stars are different colors and distances. The system on the left side of the graphic shows a star that is deep orange and appears to be very active, with dark and light spots and large flares. It appears to be close to the planet. The planet is gray and looks airless. The left quarter of the hemisphere is lit by the star, with a sharp boundary between the lit and dark sides. Text below the planet reads, “More high-energy light from the star. Atmosphere less likely.” The system on the right side of the graphic shows a star that is yellower and appears to be less active and farther away from the planet. The planet is blueish white with swirling clouds. The left quarter is lit by the star. The boundary between the lit and dark sides is fuzzy. Text below the planet reads, “Less high-energy light from the star. Atmosphere more likely.”
October 1, 2025 at 6:42 PM
kellylepo.bsky.social
The Sequoia trees here are indeed large.
Me standing under a giant Sequoia tree. It almost looks like a normal tree, until you realize that I am tiny in comparison. It's at least twice as wide as I am tall, and you can only see the base of the tree. It continues up out of the frame. The bottom has a large fire scar, where the bark was burned in a previous fire.
September 14, 2025 at 12:09 AM
kellylepo.bsky.social
Pre-show organ music and JWST images at the Fox Theater in Visalia.
September 12, 2025 at 6:17 AM
kellylepo.bsky.social
This week I'm in California for the Sequoia and Kings Canyon Dark Sky Festival.

Tonight we kicked off the festivities in Visalia with a screening of Cosmic Dawn followed by a Q&A.

I'll be giving a public talk about how JWST finds its way in space and time on Sunday at 7:30 pm at the Wuksachi Lodge
The Fox theater in Visalia, CA at night. Above the theater the name "Fox" and a clock are lit up in neon lights. It is 8:00. The marquee reads "Free Movie Cosmic Dawn, Sponsored by Sequoia Parks Conservatory, 9/11 6pm."
September 12, 2025 at 5:33 AM
kellylepo.bsky.social
I wish I took more photos when I was there, but this is me at the gift shop of Stark Trek experience when I was at Star Trek: Las Vegas in 2006.

I was very committed to having a wedding on the bridge of the Enterprise D, I was sad that it closed before I could.
A 21-year-old Kelly in a blue Star Trek Enterprise jumpsuit looking surprised at a life-sized Borg Queen. A 21-year-old Kelly in a blue Star Trek Enterprise jumpsuit standing next to a life sized Ferengi waiter from Quark's bar. I'm trying to mimic his crossed arm pose. I have red eyes from the camera flash.
August 31, 2025 at 1:27 AM
kellylepo.bsky.social
Happy #NeutronStarWeek!

Want to get a start on your astronomy-themed Halloween programming?

Check out the webinar and resources from NASA's Universe of Learning Science Briefing - Cosmic Chills: Vampire Stars, Black Widow Pulsars, and Dark Energy.

www.universe-of-learning.org/contents/eve...
An illustration of an ominous, green bat that emerges from the cosmos, pushing objects like galaxies and stars further apart into the void of outer space.
August 20, 2025 at 6:40 PM
kellylepo.bsky.social
I'm Kelly. I'm an education and outreach scientist based at @stsci.edu in Baltimore. I help make the discoveries of space telescopes like JSWT accessible to everyday people.

I also made @arpbot.bsky.social that posts pictures of cool-looking interacting galaxies.
Me recreating a famous image from the movie Contact. I'm standing below one of the radio dishes from the Very Large Array. I'm wearing a straw hat, holding large over-the-ear headphones to my ears, and staring off into the distance, as if I'm thinking about signals from alien civilizations. My long hair is in two braids. Photo of me giving a presentation in front of a huge screen showing a picture of a nebula. The image is scattered with stars that have JWST's characteristic 8-pointed diffraction spikes. The Webb telescope logo is in the corner of the image. I'm wearing a sparkly tiara and several glow necklaces. My long hair is in tight waves.
August 20, 2025 at 5:08 PM
kellylepo.bsky.social
While the foreground galaxy is warping the light from the background galaxy, they are nowhere near each other, so they are not gravitationally interacting.

I'm not sure of the exact separation, since there is nothing published about this pair, but they are probably billions of light years apart.
This ray diagram, which traces the path that light takes, illustrates how light from a distant galaxy or star can be bent by the gravity of an intervening galaxy cluster. Light from a galaxy in the top left corner of the diagram is shown moving toward Earth at the bottom right corner. Between the distant galaxy and Earth, in the center of the diagram, is a depiction of a massive galaxy cluster: A series of gold dots representing galaxies of various sizes scattered across the center of the scene. Solid white lines that end in arrows show the actual paths of the light from the distant galaxy as it travels to Earth. Dashed white lines with arrows show the paths the light would have taken had it not been bent by the gravity of the intervening cluster. The solid white lines start out straight in the beginning, but when they reach the intervening central galaxy cluster, two of the three light paths (the left and right) are bent by the cluster’s gravity and redirected toward Earth. The third solid white line (middle) travels straight from the distant galaxy through the galaxy cluster to Earth. The dashed white lines begin at the middle of the cluster, at left and right, and continue on a straight path.
August 14, 2025 at 4:16 PM
kellylepo.bsky.social
No one quoting that particular "Harvard Astronomer" should be taken seriously.
And I know Loeb can do the work — making “Harvard astronomer” the scientific equivalent of “Florida man” didn’t just happen; it took long-term dedication. I want to believe Loeb and collaborators can delve once more into literature they aren’t familiar with, boldly ignore key papers and misquote others, tear down the barriers between science and sloppy statistics, and once again find bold and inspiring ways for aliens to be hiding under every asteroid, meteor and comet, all in the fashion to which we’ve all grown accustomed.
August 8, 2025 at 8:17 PM
kellylepo.bsky.social
Congrats on being verified @stsci.edu.

You are now in the club with such luminaries as
@neorsd.org and @cpsc.gov.
Screenshot of the handle for the Space Telescope Science Institute, @stsci.edu. It has a blue check after it.
August 7, 2025 at 2:53 PM
kellylepo.bsky.social
The Space Telescope Science Institute's MAST archive contains 300 million astronomical observations from over 23 different missions.

Here is an animation showing how the archive has built up over time.

Credit: Julie Imig, STScI
August 1, 2025 at 1:16 AM
kellylepo.bsky.social
Exoplanets Program Guide Includes:

• Observe, Think, Wonder or Cosmic Stories warmup
• Build a scale model of the TRAPPIST-1 system
• Make Your Own Exoplanet Model — Describe an exoplanet and bring it to life through poster artwork or paper-mache.

universe-of-learning.org/informal-edu...
Cosmic Canvas: Exoplanets Program Guide Exploring the Universe through Art and Astronomy Above: This scientific illustration shows the seven Earth-sized planets of TRAPPIST-1, an exoplanet system about 40 light-years away from Earth, based on data as of February 2018. Credit: NASA/JPL- Caltech/R. Hurt, T. Pyle (IPAC) Astronomy and the Arts: How are they connected? In astronomy, the process of scientific inquiry mirrors the creative journey of artmaking in many ways. Just as artists observe, interpret, and reflect the world through music, painting, sculpture, and writing, scientists observe the cosmos, interpret data, and create models to understand its many mysteries. Artistic expression, scientific illustration, and modeling play pivotal roles in exploring the universe and conveying ideas, particularly when faced with the unknowns of the vast and challenging-to-observe universe. In this program guide, participants will practice skills used in both science and artmaking while learning about exoplanets. NASA's Universe of Learning
July 25, 2025 at 8:42 PM
kellylepo.bsky.social
Stellar Evolution Program Guide Includes:

• Observe, Think, Wonder or Cosmic Stories warmup
• Construct a Star Life Cycle Bookmark
• Paint a Star-forming Nebula — Use watercolors to depict how stars, dust, and gas interact in star-forming regions.

universe-of-learning.org/informal-edu...
Cosmic Canvas: Stellar Evolution Program Guide Exploring the Universe through Art and Astronomy Above: This artist’s concept shows two stars known as HM Sagittae, where a white dwarf star is pulling material from its red giant star companion. Credit: NASA, ESA, Leah Hustak (STScI) Astronomy and the Arts: How are they connected? In astronomy, the process of scientific inquiry mirrors the creative journey of artmaking in many ways. Just as artists observe, interpret, and reflect the world through music, painting, sculpture, and writing, scientists observe the cosmos, interpret data, and create models to understand its many mysteries. Artistic expression, scientific illustration, and modeling play pivotal roles in exploring the universe and conveying ideas, particularly when faced with the unknowns of the vast and challenging-to-observe universe. In this program guide, participants will practice skills used in both science and artmaking while learning about the life cycles of stars, known as stellar evolution. NASA's Universe of Learning.
July 25, 2025 at 8:42 PM
kellylepo.bsky.social
That one was actually Stephan's Quintet (and also one of JWST's first images).

webbtelescope.org/contents/med...

Credit: NASA, ESA, CSA, STScI, u/RubixsQube
July 15, 2025 at 7:00 PM