Josh Hopkins

A green fuzzy dot on a purple background

Volatile time! As anticipated for a comet ☄️, interstellar object 3I/ATLAS is now showing water - thanks to OH emission seen by Swift in the UV. A little distant at 3.51 au, but that suggests it could be from water ice grains in the coma.
Xing et al., ApJL submitted 🔭 arxiv.org/abs/2508.04675

Some real numbers on Juno. After its insertion into its initial Jovian orbit, the estimated remaining propellant mass was 785 kg. Loeb et al. assumed they had 2032 kg to work with to get their needed Del V of 2.7 km/s.

www.jpl.nasa.gov/news/press_k...

Every reputable expert I know considers mRNA vaccine technology to be one of the most revolutionary advances in medicine in our lifetimes. Its inventors won the Nobel Prize in 2023. Shutting it down now is pointless self-harm to humanity.

A fuzzy white dot on a blue background, with surrounding contour lines

3I/ATLAS measurement from HST is in: can see the coma but not the nucleus. Sets effective nuclear radius of r < 2.8 km (H>15.4), significantly smaller than earlier estimates (as anticipated).
Jewitt et al, (submitted?) arxiv.org/abs/2508.02934 🔭☄️

I did not know Dr. Jones, but his Apollo Lunar Surface Journal has been an invaluable resource since the early days of the internet. One of the first places I point people to for nuts-and-bolts level details of the Apollo missions. It was obviously a labor of love, with emphasis on both words.

I have been fortunate enough to have seen several orbital launches. The interesting thing about a New Shepard launch is that instead of heading for the horizon, it just goes straight up, up, up. And then, several minutes later, it comes right back down. And then, the capsule lands. Kinda wild.

I was fortunate to go see a New Shepard launch in person back in April. (Yes, the one that got all the media attention.) It's very impressive that Blue is now flying these on a regular, and fairly rapid cadence.

Dr. Loeb has persuaded Congresswoman Luna to write a letter to the NASA acting administrator endorsing sending Juno to comet 3I/ATLAS in case it is an alien spaceship.
lweb.cfa.harvard.edu/~loeb/APL_NA...

I don't even know what to say. (Other than that 3I is not a spaceship.)

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

One thing that's getting better in America:
When I was a kid, bald eagles were nearly extinct. I never expected to see one. There were fewer than 500 breeding pairs at the low point. But their population has recovered dramatically. I've seen four or five in the last couple of years.

Comic. [two people in labcoats look at body pierced with blade draped over bench] PERSON 1: We found him lying uncomformably on the lab bench. I wonder if the iron-rich intrusion in his back is related. PERSON 2 with ponytail: It could be clastic. Maybe a rift opened in his body, and the intrusive material later fell into the hole. [caption] The Geology Department Investigates Their First Murder

Geology Murder

xkcd.com/3112/

If I had said this last year, that Trump would try and deport US citizens in his first year, all Republicans and a nontrivial number of liberals and centrists would have attacked me for behind hyperbolic, and fear-mongering, and of having Trump Derangement Syndrome.

And yet:

UPDATE on our new interstellar friend #A11pl3Z:
Citizen scientist Sam Deen has found earlier observations of from June 25-28, from the ATLAS telescope!

Now with 6 days' worth of data, the eccentricity of A11pl3Z's trajectory is narrowed down to e=10.4 ± 1.1!
... that's undoubtedly interstellar.
🔭☄️

The phrase “fossil fuel” doesn’t mean coal and oil come from ancient, dead things. Fossil is an old word that meant “dug up from underground.” The term was applied separately to various minerals, and “fossil fish” or similar stony traces of ancient life, and to subterranean fuel like coal and oil.

venerable 75-meter lovell radio telescope (manchester) made of lego 🔭
www.manchester.ac.uk/about/news/s...

#OTD June 25, 1894 Hermann Oberth, one of the founders of modern rocketry (along with Goddard and Tsiolkovsky) was born.

contactlight.de
forallmankind.de

If I had a calculator that gave me the wrong answer even 1% of the time I’d be extremely skeptical of using that calculator. But it’s good enough for most people and we’re just going to live with the consequences.

I watched the original Mission: Impossible movie again recently, and was reminded that when Tom Cruise's character searches "the internet" for the bad guy, he searches Usenet. It came out in May 1996, so the internet changed a lot (Netscape release?) between when script was written and the premiere.

Comic. [planets and astronomical bodies in various shapes with comments pointing to them] Typical Exoplanet System: Giant planet orbiting so close that it’s actually rolling on the star’s surface; Hot Jupiter; Mini Neptune; Planet that could be habitable, if there’s a form of life that hates water but loves acid and being on fire; Cold Jupiter; Potentially habitable void; Hot Mars; Planet that may actually be in the habitable zone, according to a very optimistic modeling paper by some desperate postdocs; There’s a pulsar here but it’s probably fine; A waterworld paradise with beautiful oceans and warm— Wait, no, we just got new measurements, it’s a hellish steam oven; Mini Pluto; Earthlike data artifact; Wet Saturn; Either a gas giant or a fist-sized rock, depending which calibration method you use; Faint dust cloud that will cause several papers to be retracted; Somehow this whole system is smaller than the orbit of Mercury?!; Planet whose surface may host conditions suitable for rocks

Exoplanet System

xkcd.com/3103/

This is, I believe, the first operational launch of Angara 5. It has been in development for so long that International Launch Services agreed to pay $68M way back in 1999 for the rights to market it internationally, alongside mainstays like Atlas III and Proton K.

Typo correction - you wrote that this is a horizontal take-off configuration, but it's actually a vertical take-off, horizontal landing booster.

Source: Huang Feng-hsin

Taiwan will hold a ceremony to retire its entire F-5E/F and RF-5E fleet at Hualien Air Base on 7/4.

F-5s have been in service in Taiwan since 1965 and have recently served as jet trainers.

Goodbye, Tiger, thank you for your service.

Wow. China's Tiangong space station transiting Jupiter, captured by 沈老思347 and shared via China航天
m.weibo.cn/detail/51753...

The Philippine Mars seaplane has been reassembled at its final home in the Pima Air and Space Museum, so I'm re-upping my thread on the last of the giant seaplanes, and last Glenn L Martin aircraft to fly.

Delighted to see this honour for Alan Gilmore and Pam Kilmartin. 50+ years of planetary defence work, quiet, unheralded and essential. 🧪🔭🇳🇿

Some cool "Buran" video, including mounting it on the mighty AN-225.

Russian commentary.

Today, Ukrainian intelligence launched 117 attack drones from trucks that had been placed near Russian air bases. I tasked several collects this morning via Umbra and my first images have already started processing. What a remarkable success in a well-executed operation.

The fire at the Olenya airfield, Murmansk region, in Russia is so significant that it covers the entire eastern horizon seen from the nearby city of Olenegorsk.

The NASA planetary science fleet chart. It shows two spirals with missions to Moon/Mars and the Solar System. I’ve crossed off all of the missions that will be cancelled in the president’s budget… and there are a lot of them.

The NASA planetary science fleet chart if the president’s budget is enacted.