Kelly Lepo

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.

Not quite as good as last night, but you could see faint aurora tonight from north of Baltimore, MD. 🔭🧪

A two frame meme from Seinfeld. The top frame is a picture of Jerry basking in a red glow. "Good lord! Whats happening in there?" The bottom frame is Kramer in his doorway, also basked in a red glow. "Aurora borealis."

My entire timeline rn.

Aurorasaurus - Reporting Auroras from the Ground Up Friends, see my real-time #aurora report on the aurorasaurus.org map! Follow us on www.facebook.com/aurorasaurus.org. Reporting #northernlights and #citizenscience from the ground up since 2012!

Submit them to Aurorasaurus!!! They're an NSF funded project out of University of New Mexico that takes crowdsourced aurora observations for research purposes:
www.aurorasaurus.org

We are experiencing a big solar storm tonight, so this is quite unusual!

Look towards the northern horizon. You might be able to see a faint, green glow. Your phone will see it better than your eyes. Although the clouds have rolled in, so you might have to wait for a break in the clouds.

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.

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.

Auroras from north of Baltimore, MD.

Taken with a long exposure on my phone. They are just barely visible to the naked eye. 🔭🧪

Lunar Laser Ranging experiments - Wikipedia

yes darth. we get this question a lot. i usually tell them about the retroreflectors on the moon.

we shine lasers at the reflectors left by the apollo astronauts to measure how far away the moon is!
en.wikipedia.org/wiki/Lunar_L...

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!

YouTube video by Kelly Lepo Sci-Comm Demon Hunters - Astronomy on Tap Baltimore

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

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

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 🔭🧪⚛️☄️

I'll be there with a very special intro video. Hint: 🦖

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 ! 🔭

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.

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

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.

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!

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.

Artist's concept showing a distant star, with two rocky planets in the foreground. One planet is larger than the other.

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 🔭 🧪

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, ...

Are you looking for our Public Lecture Series? The 2024 and 2025 lectures are now available on this YouTube channel playlist. 🔭 🧪

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.

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)

Kareem El-Badry Expanding our knowledge of binary star systems, black holes, and other wonders of the universe.

Glad to see an amazing astronomer on the list of MacArthur awards this year - congrats to Kareem El-Badry! 🔭
www.macfound.org/fellows/clas...

Forgot to add 🔭 for the feed.

Planning and Scheduling Observations with Hubble and Webb

Interesting article on the technical details of how Hubble and JWST observations are scheduled, from the STScI newsletter.

www.stsci.edu/contents/new...

Also known as Arp 189.

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.

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

And I'm glad we were finally able to get this article published yesterday, before the government shutdown meant that NASA is no longer updating its website.

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.

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.

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.”

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...

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.

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... 🔭 🧪 ☄️

Astro-color alchemists Astronomers have a method for colorizing grayscale images from various space- and groundbased observatories.

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!

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:

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