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kellylepo.bsky.social
Kelly Lepo
@kellylepo.bsky.social
3.2K followers 340 following 1.1K posts
Astronomer | Science communicator | Adult Lisa Simpson
Education and Outreach Scientist at the Space Telescope Science Institute (@stsci.edu) supporting JWST.
Personal account — Views are my own
Also on Mastodon: @KellyLepo@scicomm.xyz
Posts Replies Media Videos
Reposted by Kelly Lepo
hbhammel.bsky.social
3I/ATLAS is behaving just as a comet should. No shenanigans. Looking forward to the possibility of JUICE (a European spacecraft heading eventually to Jupiter) observing this object in the coming weeks!
marshall-eubanks.bsky.social Marshall Eubanks @marshall-eubanks.bsky.social · 13d
I have just received from Kevin Walsh of SWRI a re-analysis of the PUNCH data for 3I/ATLAS, & have redone our gas and dust coma prediction models as a result. These new data agree well with the independent reductions of Thomas Lehmann and bode well for the Juice observations starting November 2nd.
Magnitude estimates for the interstellar object 3I/ATLAS.
October 31, 2025 at 3:28 PM
kellylepo.bsky.social
A video I made for last night's @aot-baltimore.bsky.social event.

A group of astronomers must defeat a group of demon paleontologists who are trying to steal their fans 🔭 🦖

youtu.be/PCAPX1UjTWA
Sci-Comm Demon Hunters - Astronomy on Tap Baltimore
YouTube video by Kelly Lepo
youtu.be
October 30, 2025 at 10:13 PM
Reposted by Kelly Lepo
ligo.org
We are pleased to announce our discovery of #GW241011 and #GW241110

Both come from binary black holes where one black hole is much larger than the other. The larger black holes have large spin. Could these black holes have formed in a previous merger?

ligo.org/science-summ...

#O4IsHere 🔭🧪⚛️☄️
Infographic about GW241011 and GW241110 GW241011's source contained black holes about 13 and 8 times the mass of our Sun. The spin of the bigger black hole is high and bear aligned with the orbit. GW241110's source contained black holes about 17 and 8 times the mass of our Sun. The spin of the larger black hole is high and near anti-aligned with the orbit. Credit: Shanika Galaudage/Northwestern University/Adler Planetarium
October 29, 2025 at 1:58 PM
kellylepo.bsky.social
I'll be there with a very special intro video. Hint: 🦖
aot-baltimore.bsky.social Astronomy on Tap Baltimore @aot-baltimore.bsky.social · 14d
Astronomy on Tap is happening TOMORROW!

Come join us at Guilford Hall Brewery starting at 7:30 pm (doors open at 7:00 pm) for a spooky evening of astronomy trivia, beer, and space knowledge!

(Costumes not required, but encouraged.)
a skeleton with a pumpkin head is standing in front of a gravestone that says r.i.p.
ALT: a skeleton with a pumpkin head is standing in front of a gravestone that says r.i.p.
media.tenor.com
October 27, 2025 at 10:22 PM
Reposted by Kelly Lepo
astroerika.bsky.social
Want to know more about my recent paper about this cool geriatric white dwarf eating its planets? 🤩

It’s all detailed in this news article by @stsci.edu ! 🔭
stsci.edu Space Telescope Science Institute @stsci.edu · 19d
Astronomers have found a rare, ancient planetary system 145 light-years away, where a white dwarf star is actively consuming debris from a disrupted planet—the oldest and most “polluted” disk ever seen around such a star: https://bit.ly/47mYktj 🔭 🧪
At image center is a small, white star against a gray background. It is surrounded by a large translucent disk with rings and gaps that extends from upper left to lower right. In the foreground, irregular chunky rocks are floating in space along the bottom of the frame. A stream of material extends from lower right toward the central star. The words, artist’s concept are at lower left.
October 22, 2025 at 2:22 PM
Reposted by Kelly Lepo
wikipedia.org
The answer to the Olbers' paradox lies in cosmic history: stars have not existed forever, and light from the most distant galaxies is stretched by the expansion of space.

Expand your knowledge about our expanding universe ➡️ w.wiki/3BFu
A diagram illustrating mipmapping, showing texture detail decreasing with distance from the viewer's perspective. Text says: If the universe is filled with countless stars, why isn’t the night sky ablaze with light? Known as Olbers’ paradox, this mystery reveals that the universe has a finite age and is expanding.
October 15, 2025 at 2:45 PM
Reposted by Kelly Lepo
benjaminpope.bsky.social
Thrilled to have two years' of work out, in a pair of papers led by @gradientrider.bsky.social and @maxecharles.bsky.social.

We've built a data-driven calibration of the James Webb Interferometer to near its fundamental limits for high-res imaging - explainer at @aunz.theconversation.com!
How we sharpened the James Webb telescope’s vision from a million kilometres away
The only Australian hardware on board the legendary telescope is starting to fulfil its duties.
theconversation.com
October 14, 2025 at 3:35 AM
Reposted by Kelly Lepo
theplanetaryguy.bsky.social
Layoff notices at JPL are going out today.

About 11% of the Lab, or 550 people, are being let go.

I'm thinking of my friends and colleagues there, some of whom will still be employed after today and some of whom won't.

I'm sorry you're having to deal with this.
October 14, 2025 at 6:24 PM
Reposted by Kelly Lepo
stsci.edu
Why do some rocky planets have atmospheres when others don’t? #NASAWebb and Hubble space telescopes are teaming up to find out. ➡️ https://go.nasa.gov/47a9fFD 🔭 🧪
Artist's concept showing a distant star, with two rocky planets in the foreground. One planet is larger than the other.
October 14, 2025 at 2:56 PM
Reposted by Kelly Lepo
stsci.edu
Are you looking for our Public Lecture Series? The 2024 and 2025 lectures are now available on this YouTube channel playlist. 🔭 🧪
STScI Public Lecture Series - YouTube
The STScI Public Lectures Series held monthly presentations on all aspects of astronomy and space telescopes for several decades. Due to changes in funding, ...
youtube.com
October 13, 2025 at 7:17 PM
Reposted by Kelly Lepo
marspidermonkey.bsky.social
As a primatologist, Jane Goodall was a huge inspiration to me. I admired the way she describes chimpanzee behavior with such detail and empathy, and she’s inspired so many people and advocated for chimpanzee conservation and welfare.

However, I'm dismayed at what her narrative leaves out (1/10)
Photo of Jane Goodall in the center, signing a book, with three women standing slightly hunched behind her. A very young Michelle is to the right, smiling.
October 2, 2025 at 4:18 PM
Reposted by Kelly Lepo
jradavenport.com
Glad to see an amazing astronomer on the list of MacArthur awards this year - congrats to Kareem El-Badry! 🔭
www.macfound.org/fellows/clas...
Kareem El-Badry
Expanding our knowledge of binary star systems, black holes, and other wonders of the universe.
www.macfound.org
October 9, 2025 at 4:37 PM
kellylepo.bsky.social
Interesting article on the technical details of how Hubble and JWST observations are scheduled, from the STScI newsletter.

www.stsci.edu/contents/new...
Planning and Scheduling Observations with Hubble and Webb
www.stsci.edu
October 9, 2025 at 4:49 PM
Reposted by Kelly Lepo
arpbot.bsky.social
Also known as Arp 189.
pomarede.bsky.social Daniel Pomarède @pomarede.bsky.social · Oct 5
CFHT Astronomy Image Of The Month

The Umbrella Galaxy (NGC 4651)

Credits: data obtained using the MegaCam camera on the Canada-France-Hawaii Telescope; image by Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum); copyright © 2025 CFHT
www.cfht.hawaii.edu/HawaiianStar... 🧪🔭
A photography of the spiral galaxy NGC 4651. This member of the Virgo Cluster is known as the Umbrella Galaxy due to the umbrella-shaped structure that extends from its disk and that is composed of stellar streams, being the remnants of a much smaller galaxy that has been torn apart by NGC 4651's tidal forces.
October 7, 2025 at 3:44 AM
Reposted by Kelly Lepo
arpbot.bsky.social
Image of Arp 85, also known as the Whirlpool Galaxy or M51, from Halton Arp's Atlas of Peculiar Galaxies (1966).

In the original catalog it was in the category: Spiral galaxies - Large, high surface brightness companions.
Source
A grainy, black and white image of two galaxies. The larger of the two galaxies, a spiral, is on the left side of the image. Two well-defined arms extend to from its center and form loose spirals around the middle. The smaller galaxy on the far-right side is fuzzy sphere. The view of this smaller galaxy is partially obstructed by the tip of one of the arms of the spiral galaxy, which appears to cover the top third of the smaller galaxy. Many white dots, stars, are seen on the black background.
October 2, 2025 at 12:31 AM
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
Reposted by Kelly Lepo
science.esa.int
Stars in our galaxy make a stadium wave, Gaia finds 🙌

Our Milky Way galaxy never sits still: it rotates and wobbles 🌀

But #ESAGaia has just revealed that our galaxy also has a giant wave rippling outwards from its centre 👉 www.esa.int/Science_Expl... 🔭 🧪 ☄️
This image consists of two sides. Left side: A top-down view of a spiral galaxy is shown. It has a bright central bulge with several spiral arms radiating outward. Overlaid on the lower part of the galaxy is a data visualisation, with colours ranging from blue to red. A label reading ‘Sun’ marks a specific location within this overlay. Right side: An edge-on view of the same spiral galaxy is presented. It reveals the galaxy's thin disc and central bulge from the side. Coloured points are scattered along the disc, representing the same data as the overlay on the left side. The image features a dark background with a thin, bright horizontal line running across the centre. This is our galaxy’s disc. Above and below this line, numerous white arrows point upward and downward. These arrows vary in length and are spread evenly along the line. Scattered among the arrows are small red and blue dots. The visual resembles an astronomical data visualisation, illustrating positions and motions of stars in our galaxy.
September 30, 2025 at 1:01 PM
Reposted by Kelly Lepo
spie.org
Space images from Hubble, Webb, Rubin, and Chandra don’t show “true” colors; they translate invisible wavelengths into visible ones. Colorization reveals hidden details and helps us understand the universe. 🔭 🛰️

Read more in the Sept/Oct issue of #PhotonicsFocus!
Astro-color alchemists
Astronomers have a method for colorizing grayscale images from various space- and groundbased observatories.
spie.org
September 25, 2025 at 3:47 PM
Reposted by Kelly Lepo
elisecutts.bsky.social
Cecilia Payne-Gaposchkin ✨ figured out what stars are made of ✨ when she was just 25. 🔭🧪

Her PhD thesis basically established the Harvard astro department — at a time when Harvard didn't officially allow woman students.

I wrote this little profile to mark the 100th anniversary of her thesis:
September 24, 2025 at 9:14 AM
Reposted by Kelly Lepo
janiceleeastro.bsky.social
One of my faves, among the galaxies that we're studying. Uncommonly beautiful because of its striking "flocculent" spiral morphology. We've learned its star clusters tell a story of gas accreted from a neighbor, rejuvenating the disk🧪🔭
iopscience.iop.org/article/10.3...
#extragalactic #astrosci
science.esa.int ESA Space Science @science.esa.int · Sep 22
Spiral, elliptical or neither? 🤔

The latest image from the NASA/ESA Hubble Space Telescope features a hard-to-categorise galaxy, NGC 2775. It has features of both elliptical and spiral galaxies – so what type is it?

Read more 👉 esahubble.org/images/potw2... 🔭
A galaxy seen face-on, with a slightly elliptical disc that appears to have a hole in the centre like a doughnut. In the hole, the core is a brightly glowing point that shines light out beyond the edge of the disc. Around the hole is an inner ring of dust, and at the galaxy’s edge is a thicker outer ring of dust, with a swirling web of dust strands in between. Blue stars and red nebulae are visible behind the dust.
September 24, 2025 at 1:34 PM
Reposted by Kelly Lepo
nws.noaa.gov
The Fall/Autumnal Equinox is TODAY at 2:19 PM EDT. That's the time at which our Sun is directly over the Earth's equator, signaling the start of Northern Hemisphere astronomical fall. The Earth’s northern hemisphere will continue to tilt further from the sun through the Winter Solstice on Dec 21.
Graphic showing Earth during the June solstice and September equinox. At the equinox, sunlight is evenly distributed along the equator. Text notes Fall Equinox 2025 occurs Sept 22 at 2:19 pm EDT.
September 22, 2025 at 1:02 PM
kellylepo.bsky.social
In case you missed it live, the recording of "Alien Skies: Exploring Distant Exoplanet Atmospheres with Webb", my conversation with exoplanet scientist Dr. Néstor Espinoza from the Space Telescope Science Institute is up on YouTube.
Alien Skies: Exploring Distant Exoplanet Atmospheres with Webb
YouTube video by Space Telescope Science Institute
www.youtube.com
September 19, 2025 at 9:29 PM
Reposted by Kelly Lepo
ligo.org
Last Sunday was the 10th anniversary of our first #GravitationalWave detection!

Join us for a thread of celebratory cakes enjoyed by members of our collaboration

First, a cake from @ozgrav.bsky.social Looks like plenty to share?

🖼️: J Powell

🧵🎂 #GW10Years
A sheet cake decorated with "Happy 10 Birthday GW150914", confetti, balloons, a binary black hole, and the data from our first detection, as well as the OzGrav logo. It is edged with some creamy frosting.
September 19, 2025 at 5:03 PM
Reposted by Kelly Lepo
jwuphysics.bsky.social
Delighted to see that this year's Ig Nobel Physics Prize is about the phase behavior of Cacio e pepe sauce.

Paper: pubs.aip.org/aip/pof/arti...

Pop Sci article: phys.org/news/2025-09...
2025 Ig Physics Nobel Prize goes to perfect pasta sauce
The Ig Nobel Prize honors research that first makes people laugh, then makes them think. Its 35th award ceremony possibly also makes people hungry: ISTA physicist Fabrizio Olmeda and colleagues resear...
phys.org
September 19, 2025 at 4:32 PM
kellylepo.bsky.social
Join us tonight at 7 p.m ET. I'll be chatting with Dr. Néstor Espinoza about how JWST is Exploring Distant Exoplanet Atmospheres.
September 17, 2025 at 10:19 PM