Dr./Prof. Meredith MacGregor

Johns Hopkins Arts & Sciences

Come join us! Reach out if you have any questions!

William H. Miller III Department of Physics & Astronomy@jhuphysicsastro.bsky.social

Johns Hopkins Physics & Astronomy invites applications for its endowed Miller postdoctoral prize fellowships: independent research in any area of the department, up to three years, starting 2027. Apply by Nov 15: academicjobsonline.org/ajo/JHU/Phys...

Dr./Prof. Meredith MacGregor reposted

@jhuartssciences.bsky.social

Three Hopkins physicists are helping build NASA's next space telescope. PRIMA will study far-infrared light to reveal how planets, stars, and black holes form, and even how water arrived on Earth, with a target launch in 2033. hub.jhu.edu/2026/09/30/n...

hub.jhu.eduNASA space telescope project advances with three Hopkins team membersBy studying radiant energy that only emerges in the far-infrared, PRIMA will provide new insight on the formation of planets, stars, black holes, and even how water on Earth came to be

skyandtelescope.orgskyandtelescope.org

Great article to learn more about PRIMA: skyandtelescope.org/astronomy-ne...

nasa.govNASA Selects Far-Infrared Telescope as First in New Mission Class - NASANASA announced Wednesday a mission to explore the history and evolution of the universe, PRIMA (PRobe far-Infrared Mission for Astrophysics), is advancing to

YES!!! LET'S GO PRIMA!!! Such a joy to be part of this wonderful team 🌌🔭🚀 www.nasa.gov/news-release...

10 Sept

One thing that sticks with me now that the SMEX proposals are all in - My daughter was born right after the initial gate review at JPL for EVE. Now, she's 2. Amongst our science team, we have had 3 more EVE babies. Really makes you realize how long it takes to develop one of these concepts! #PIDaily

8 Sept

IT IS SUBMITTED!!! I still can't quite believe it 🤩🍷🚀 #PIDaily And, if you want to learn more about the fabulous EVE team and amazing science that we will do, check out our website: sites.krieger.jhu.edu/eve/

arxiv.orgGemini and Apache Point Multi-band Optical Imaging Characterization of Fragmenting Long-period Comet C/2025 K1 (ATLAS)We present results from multi-band g, r, and i, observations of C/2025 K1 (ATLAS) taken with the Gemini North 8.1-m/GMOS imager on 2025 December 6 and December 24, and u, g, r, i, and z observations w...

1 Sept

Fun Solar System paper looking at fragmenting Comet C/2025 K1 (ATLAS) on the arXiv today led by awesome grad student Carl Ingebretsen: arxiv.org/abs/2608.29698

30 Aug

Go Roman Go! 🚀 So excited to get to work with this amazing data soon!

arxiv.orgPreparing for the Early eVolution Explorer: The Impact of Flare Temperature on Ozone Column Depth in Earth-Like AtmospheresAtmospheric photochemical models incorporating the impacts of stellar flares often assume a $\sim$9,000 K spectrum at ultraviolet-optical wavelengths. Recent multiwavelength observations, however, rev...

25 Aug

It's a big day for EVE papers on the arXiv! First up is a paper led by @jhuartssciences.bsky.social graduate student Jaime Crouse exploring the effect of flare temperature on ozone photochemistry in Earth-like atmospheres: arxiv.org/abs/2608.23548

nam02.safelinks.protection.outlook.comPreparing for the Early eVolution Explorer: Photometric Diagnostics of Magnetospheric Accretion Geometry in Young Stellar ObjectsThe inner disk truncation radius, $R_T$, plays a crucial role in the regulation of star-disk interaction and the early evolution of star-disk-planet systems; however, measuring this parameter is obser...

25 Aug

Next, is a paper by Laura Venuti presenting a new method for determining the truncation radius in young accreting systems that hinges on the color dependence of the accretion shock emission in multi-band time-domain surveys: arxiv.org/abs/2608.23351

arxiv.orgExoplanet System Architecture: Sculpting the Inner RegionsIn this study, we seek to improve our understanding of the competing roles of disk-driven and planet-planet dynamical migration in sculpting planetary system architecture in the inner $\lesssim 1.5$ a...

25 Aug

And last but not least, Mark Swain's paper looking at the competing roles of disk-driven and planet-planet dynamical migration in sculpting planetary system architecture in the inner 1.5 au of protoplanetary disks: arxiv.org/abs/2608.22649

4 Aug

I GOT TENURE!!!!!!!!!!!!!!!!!!

15 June

James Rogers gave a fantastic talk about how young planets probe planet formation at #CoolStars23 and shouted out how EVE will dramatically change our understanding of this

10 June

Now seems like a great moment to share this awesome new paper explaining how the Early eVolution Explorer (EVE) - a NASA SMEX mission concept - will transform our understanding of young planets (<50 Myr old): arxiv.org/pdf/2606.04283

arxiv.orgarxiv.org

@hannah-richter.bsky.social

9 June

Time to actually do this whole SMEX proposal thing! #PIDaily

Dr./Prof. Meredith MacGregor reposted

Hannah Richter

5 June

The OMB's sweeping proposed changes to U.S. grant funding have racked up over 6,000 comments this week. 📃🛰️ In @skyandtelescope.bsky.social, astronomers weigh in on just how destructive these ideas would be for space science: skyandtelescope.org/astronomy-ne... #trump #omb #nasa

skyandtelescope.orgProposed U.S. Grant Funding Rules Spark Worry, Backlash in AstronomyThe Office of Management and Budget envisions diminishing peer review and international collaborations.

28 May

Another crazy week - PRIMA student collaboration site visit on Tuesday. EVE STMC review today. Red eye flight tonight. Innovation for Astrophysics workshop in DC tomorrow. Sleep? Not so much 🫠#PIDaily

13 May

And this time it’s for real (and still very early) - Go PRIMA! 🌌🚀

12 May

Hello JPL! It’s 7am and I’m wearing a suit. Let’s do this 💪

28 Apr

Got an RSV vaccine! ✅ Always a good feeling when I can protect myself from getting dangerously sick from something preventable 💉

25 Apr

It’s Physics Fair day here at @jhuartssciences.bsky.social! If you’re local come check it out!

aas.orgResults of the 2026 AAS ElectionThe 2026 AAS Election closed on 20 April and the results are in!

24 Apr

Wow thanks everyone who voted for me...! I'm honored to get to have a chance to contribute to the AAS elected leadership aas.org/posts/news/2...

23 Apr

PRIMA Mock Site Visit ✅ EVE Baseline Commitment Review ✅ ALMA proposals submitted ✅ 6am flight back to BWI ✅ See you again in just a few weeks JPL! #PIDaily

23 Apr

Also, I seriously need a nap 😴

20 Apr

Last piece of space pottery for the Physics Fair next weekend! I made these bowls to look like the interstellar medium - the space in between stars. Love how the glaze pops in the sunlight 🌌

17 Apr

First attempt at sgraffito - I really like how the combo of black underglaze with the white clay (Standard 182) came out looking like chalk on a chalkboard #sciart #pottery

13 Apr

Finished the full set of Solar System trinket dishes I shared earlier! #sciart

11 Apr

In honor of the successful landing of Artemis II, here’s a moon bowl! I made the bowl and then cratered it to look like the surface of the moon #sciart

3 Apr

I started making ceramics last summer and it has become a big part of my life that I haven’t shared here yet. For our annual department outreach event, I agreed to make space inspired pottery for prizes and giveaways. I’ve started getting final pieces out of the kiln and it’s so fun I have to share!

3 Apr

First up are little trinket dishes that I hand painted with Solar System planets. There will be one for every planet in the end but not all of them have been fired yet.

1 Apr

We’ve never gone to the Moon since I’ve been alive - until now. There’s A LOT awful going on, but it was still so amazing to watch the Artemis II launch. What amazing things us humans are capable of 🚀🌔

1 Apr

(Also an interesting moment watching the launch while getting off an airplane in Atlanta and realizing how many people had no idea this was happening)

apod.nasa.govAstronomy Picture of the Day A different astronomy and space science related image is featured each day, along with a brief explanation.

6 Mar

Always a fun day when your research ends up on APOD! 🤩 apod.nasa.gov/apod/astropi... And, check out the original paper, too: iopscience.iop.org/article/10.3...

arxiv.orgThe Landscape of Undergraduate Astronomy and Astrophysics Degree RequirementsIn this document we summarize the results of a survey of undergraduate degree-granting programs conducted by the 2024-2025 American Astronomical Society Education Committee's Subcommittee on UndeRgrad...

5 Feb

Our AAS Education Committee report on 'The Landscape of Undergraduate Astronomy and Astrophysics Degree Requirements' is now available on arXiv: www.arxiv.org/abs/2602.03959. Please give it a read!

aas.orgAAS Working Group Recommends New Best Practices for Graduate AdmissionsThe Working Group on Graduate Admissions wishes to highlight two recommendations for immediate adoption by the community to improve the current astronomy-wide graduate admissions process.

29 Jan

Some new recommendations from our AAS Working Group on Graduate Admission: aas.org/posts/news/2...

8 Jan

So excited to see our EVE science highlighted in Evgenya Shkolnik’s fantastic plenary at #AAS247! I’m thrilled to be proposing this mission to NASA

It’s far-infrared day at #AAS247! Come learn about how cool this part of the spectrum is and why it is critical for a multi-wavelength understanding of the universe!

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And now it’s the PRIMA special session in Room 224B!

IRSTIG splinter now in Room 231!

It’s far-infrared day at #AAS247! Come learn about how cool this part of the spectrum is and why it is critical for a multi-wavelength understanding of the universe!

First up are a bunch of talks (including mine!) about the POEMM balloon mission in the 10am session in Room 222C

6 Jan

Our session for the AAS Task Force on Graduate Admissions is this morning at 10am in Room 226 B #AAS247

5 Jan

Come join us in the session discussing our report on the landscape of undergraduate degrees in astronomy and astrophysics at #AAS247 in room 226B!

5 Jan

What a great birthday present today - SMEX is back on! Let’s go EVE!

arxiv.orgJWST TRAPPIST-1 e/b Program: Motivation and first observationsOne of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST tr...

10 Dec 2025

Pretty excited to be part of this awesome team doing super cool science! arxiv.org/abs/2512.07695

Dr./Prof. Meredith MacGregor reposted

Ward Howard

@wardhoward.bsky.social

4 Dec 2025

1/ It's press day!🔭🧪 We apply a grid of time-dependent physical models to explain TRAPPIST-1 flares, predicting the X-ray & UV flux driving escape and photochemistry in planetary atmospheres, and correcting flare contamination in transit spectroscopy down to ~60 ppm: www.colorado.edu/today/2025/1...

colorado.eduNew research on flares from a hot-tempered star could inform search for habitable planetsA new study takes a close look at TRAPPIST-1, a little star roughly 40 light-years from our sun that hosts seven Earth-sized planets.

21 Nov 2025

Today is the ExoJamboree at @jhuartssciences.bsky.social and @stsci.edu - How cool is that we are such a powerhouse of exoplanet research here that we can have an awesome conference with just local people?!?!

scientificamerican.comAlien Comets Swarm around Other StarsComets don’t just orbit our sun. “Exocomets” are common around other stars in the galaxy, too

21 Nov 2025

Another wonderful article about our RZ Psc work!

Phil PlAIt@philplait.bsky.social

I was tempted to make this post "Avi Loeb Claims Millions of Spaceships Found" but decided against it. www.scientificamerican.com/article/alie... 🔭 🧪

14 Nov 2025

This! Here's a slide pulled from my class lecture notes this semester. Comets have two clear tails - one from dust and one from ions. They point in different directions because one feels the solar wind while the other feels radiation pressure.

Steve Desch@deschscoveries.bsky.social

Avi Loeb's calculations about 3I/ATLAS are 100% wrong because he has never understood that dust in the tail(s) responds to solar radiation pressure. Solar wind shapes the ion tail. But the radiation pressure is about 1000 times larger than the solar wind ram pressure, for particles that feel it.

nature.comA host of ‘exocomets’ swarms a distant starDimming of the starlight from RZ Piscium reveals that 24 unseen bodies are whizzing around the star.

11 Nov 2025

Nature published a research highlight on our RZ PSc exocomet paper: www.nature.com/articles/d41...