Paul Byrne
@theplanetaryguy.bsky.social
14K followers 240 following 1.9K posts
Associate Professor of Earth, Environmental, and Planetary Science at Washington University in St. Louis • Planetary Data System Geosciences Node Director • Planetary Bastard • he/him/Sir
Posts Media Videos Starter Packs
Pinned
theplanetaryguy.bsky.social
Open this photo up and look for the small, white dot just left of centre.

It looks like Venus, shining brightly in the twilight sky.

But it's us.

It's Earth.

From Mars.
theplanetaryguy.bsky.social
This is NASA Photojournal PIA21625, taken by the Cassini spacecraft on 29 May 2017. At the time, the spacecraft was about 2 million km from Titan.

Credit: NASA/JPL-Caltech/Space Science Institute
theplanetaryguy.bsky.social
Saturn's giant moon Titan.

By Cassini.
Reposted by Paul Byrne
angierasmussen.bsky.social
For more information about the Friday night massacre at CDC, I wrote up an analysis of who got terminated and what that means for public health.

Grateful to @saveamericamvmt.bsky.social for supporting and amplifying. We are in really terrible trouble.

rasmussenretorts.substack.com/p/the-death-...
Reposted by Paul Byrne
guitarwatson.bsky.social
Great work by my friend @kenjenkinsny.bsky.social. More public officials should stand up the way Ken has in Westchester.
Reposted by Paul Byrne
theplanetaryguy.bsky.social
This isn't legal.

And yet these fuckers are doing it anyway, knowing that by the time Congress and the courts* intervene it won't matter because the damage will have been done.

How can you do this to your country?

*not the Supreme Court, obv
OMB Director Russell Vought says the government layoffs -- Reductions in Force (RIFs) -- that the White House has been threatening if Congress doesn't vote to reopen the government have begun.
x.com/russvought/s...
Reposted by Paul Byrne
virginiagewin.bsky.social
Journalist here

I’m interested in talking to a federal agency scientist who was fired, then rehired. I can keep you anonymous. I’m on Signal ginnyg.04

Reposts are appreciated!
theplanetaryguy.bsky.social
This isn't legal.

And yet these fuckers are doing it anyway, knowing that by the time Congress and the courts* intervene it won't matter because the damage will have been done.

How can you do this to your country?

*not the Supreme Court, obv
OMB Director Russell Vought says the government layoffs -- Reductions in Force (RIFs) -- that the White House has been threatening if Congress doesn't vote to reopen the government have begun.
x.com/russvought/s...
theplanetaryguy.bsky.social
Everyone: this is, in fact, Mars' larger of its two potato moons, Phobos, and *not* 3I/ATLAS.
theplanetaryguy.bsky.social
You guys, I think this is the interstellar comet 3I/ATLAS.

Photographed last Friday.

From the surface of Mars by one of our nuclear-powered rovers.
A small, light-grey streak points to the bottom left in an otherwise featureless, dark background.
theplanetaryguy.bsky.social
I was thinking about what eclipses look like in that system and immediately got a headache
Reposted by Paul Byrne
kevinstalder.bsky.social
Statement from the Nobel Peace Prize Committee 👏 🙏
Reposted by Paul Byrne
flyinghabu.bsky.social
Two nights of 3:45am alarms, blazing full moon lighting the sky like daytime and washing out the light of everything else, comet included. Then two days of post-processing battles, as comet processing is maddeningly tricky.

But I finally pulled it off: here is C/2025 A6 Lemmon. 🔭

#Astrophotography
Comet C/2025 A6 Lemmon taken from my backyard
Reposted by Paul Byrne
theplanetaryguy.bsky.social
This is a new image from #JWST.

The bright points with spikes are stars in the Milky Way.

Everything else is a galaxy.

Everything. Else. Is. A. Galaxy.
theplanetaryguy.bsky.social
The comet made its closest approach to Mars (about 30 million km) on 3 October.
theplanetaryguy.bsky.social
This image was taken by NASA's Mars Perseverance rover with its Right Navigation Camera late at a local Jezero Crater time of 9:30 pm.

Note that the image was taken *Saturday* 4 October, not Friday as the first post says.

Credit: NASA/JPL-Caltech
theplanetaryguy.bsky.social
You guys, I think this is the interstellar comet 3I/ATLAS.

Photographed last Friday.

From the surface of Mars by one of our nuclear-powered rovers.
A small, light-grey streak points to the bottom left in an otherwise featureless, dark background.
theplanetaryguy.bsky.social
Few things more unnatural than flying
Reposted by Paul Byrne
theplanetaryguy.bsky.social
But still a window seat!

To think that the overwhelming majority of humans never had the opportunity to see the world from an airplane window, and it's something we take for granted.
Reposted by Paul Byrne
theplanetaryguy.bsky.social
See that small, moving splotch?

That's 3I/ATLAS, a comet that formed in a different star system, photographed from Mars orbit by the ESA Exomars Trace Gas Orbiter.

A comet from a DIFFERENT SOLAR SYSTEM photographed by a ROBOT ORBITING MARS

last Friday