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John Forbes @redshiftless.bsky.social · 22d

More hostility than I was expecting from a planter!

A printed sign on a wooden planter with grass in the foreground and long thin green leaves in the planter. The sign says “RCG compost project; in progress; please leave”

John Forbes @redshiftless.bsky.social · 28d

Re the CRs: the age might buy you a factor of 2 relative to the solar system, but there may be a larger effect (in the same direction!) - 3I's orbit sends it further above the galactic midplane -> less B field -> more CRs

(adapted from an argument made in this paper: arxiv.org/abs/2509.04165).

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John Forbes @redshiftless.bsky.social · Aug 27

Incredible stuff happening on wikipedia

A screenshot of the top of a wikipedia page for "Why We're Polarized", the book by Ezra Klein. In the screenshot, the start of the second paragraph of the article is highlighted, "Opinion on the book is polarized"

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John Forbes @redshiftless.bsky.social · Aug 26

It is wild how many outdoor cats there are in NZ. Everyone loves the native birds, but the outdoor cat culture is really ingrained.

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John Forbes @redshiftless.bsky.social · Aug 17

Obviously peer reviewed vs. not can be an issue, but in this particular case the data in the paper seems to have been completely fabricated. I think it's fair to say that peer review generally operates on assumptions of good faith, so fake data will often make it through.

John Forbes @redshiftless.bsky.social · Aug 4

They don't seem to sell many ads on these calculator-style searches, so perhaps costing google money is the most ethical choice 🤷 (if it worked lol).

But seriously, not a bad point!

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John Forbes @redshiftless.bsky.social · Aug 4

Yeah, could be. Google has worked well for the past decade, so it feels like the end of an era.

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John Forbes @redshiftless.bsky.social · Aug 4

PSA to scientists: Google calculator appears to no longer do basic unit conversion correctly!

n.b. the correct answer here is 223.4 Myr, a factor of about 60 larger than Google's answer.

🔭 🧪

A screenshot of a google search result for "2*pi*(8 kpc)/(220 km/s)" which is roughly the time it takes the Sun to go around the Galaxy. In the screenshot, google's calculator has popped up and parsed the expression correctly, but then returns the result 3 899 243.9 years, and answer which is off by 2 orders of magnitude.

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Reposted by John Forbes

cira-csu.bsky.social @cira-csu.bsky.social · Aug 1

Crew-11 lifts off from Florida on their way to the International Space Station.

The heat signature from the launch could be seen from GOES-18.

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Reposted by John Forbes

cira-csu.bsky.social @cira-csu.bsky.social · Jul 28

Cumulus clouds swirl along the Gulf Coast.

This mesmerizing view captured yesterday by GOES-19.

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Reposted by John Forbes

Marina Koren @marinakoren.bsky.social · Jul 24

I wrote about Rubin again, this time about the telescope's capacity to find potentially dozens of interstellar objects.

It's going to be wild, as one astronomer put it, "like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it."
www.nationalgeographic.com/science/arti...

Are interstellar objects proof of alien life? This could finally settle the debate.

The Vera Rubin telescope is poised to kick off an explosive era of discovery. "It's like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it. It's going to be fun."

www.nationalgeographic.com

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Reposted by John Forbes

Michele Bannister @astrokiwi.bsky.social · Jul 21

It's paper day! The first science paper with data from @vrubinobs.bsky.social's survey camera, the mighty LSSTCam, is a VERY quick turnaround of Rubin's observations thus far of interstellar comet 3I/ATLAS. ☄️
Chandler et al., submitted 🔭
A 🧵

NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1)

We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin ...

arxiv.org

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John Forbes @redshiftless.bsky.social · Jul 16

I don't know about "the best," but my April Fool's rant is my personal contribution to this genre. arxiv.org/abs/2003.14327

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Reposted by John Forbes

Michele Bannister @astrokiwi.bsky.social · Jul 9

It's paper day! We use our Ōtautahi-Oxford model of the Galaxy's interstellar object population to understand the origins of 3I/ATLAS, from only its velocity
@astrohopkins.bsky.social, Dorsey, @redshiftless.bsky.social, @astrokiwi.bsky.social, @chrislintott.bsky.social & Leicester, submitted
A 🧵🔭

From a Different Star: 3I/ATLAS in the context of the Ōtautahi-Oxford interstellar object population model

The discovery of the third interstellar object (ISO), 3I/ATLAS (`3I'), provides a rare chance to directly observe a small body from another Solar System. Studying its chemistry and dynamics will add t...

arxiv.org

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John Forbes @redshiftless.bsky.social · Jul 2

If this holds up it will be the 3rd interstellar object (comet or asteroid from another star system). Not every day we get to increase the sample by 50%!

168 hr arc = observed over a period of 1 week so far, and e~9 meaning convincingly interstellar (anything >~1 is not bound to the Sun).

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John Forbes @redshiftless.bsky.social · Jul 2

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John Forbes @redshiftless.bsky.social · Jun 5

It's my favorite time of the year: new black-footed ferret kits born at the National Zoo and the return of ferretcam!

nationalzoo.si.edu/webcams/blac...

A screenshot from a livestream filmed with an infrared camera in grayscale, showing a sleeping adult ferret in a container on a bed of paper squares(?) with an indeterminate number of ferret kits (turns out there are 8!)

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John Forbes @redshiftless.bsky.social · Jun 1

Looks like a promising night for aurora chasing

A screenshot from the Aurora app showing KP forecasts as a function of time:
Now: 3.0
1800: 4.0
2100: 3.67
Midnight: 7.67
0300: 7.67
0600: 7.33

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John Forbes @redshiftless.bsky.social · May 13

As far as I can tell this month is just 8 deadlines in a trenchcoat.

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Reposted by John Forbes

Danny Caballero 🇲🇽💚🤍 @danny.hellmo.space · May 10

#SaveNSF

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Reposted by John Forbes

Kate Marvel @drkatemarvel.bsky.social · Apr 22

Astronomers have found thousands of planets outside the solar system. All of them are, to my knowledge, garbage. Happy Earth Day to the only good one 🌍

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John Forbes @redshiftless.bsky.social · Apr 18

Bad stats (and not a convincing biosignature in the first place) bsky.app/profile/dist...

Dr Ryan MacDonald @distantworlds.space · Apr 17

𝗡𝗼, 𝗮 𝗯𝗶𝗼𝘀𝗶𝗴𝗻𝗮𝘁𝘂𝗿𝗲 𝘄𝗮𝘀 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗱𝗲𝘁𝗲𝗰𝘁𝗲𝗱 𝗶𝗻 𝗞𝟮-𝟭𝟴𝗯'𝘀 𝗮𝘁𝗺𝗼𝘀𝗽𝗵𝗲𝗿𝗲.

K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.

Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).

🔭🧪🪐 #exoplanet

Artist's impression of the exoplanet K2-18b.
Credit: A. Smith, University of Cambridge.

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Reposted by John Forbes

Dr Ryan MacDonald @distantworlds.space · Apr 17

𝗡𝗼, 𝗮 𝗯𝗶𝗼𝘀𝗶𝗴𝗻𝗮𝘁𝘂𝗿𝗲 𝘄𝗮𝘀 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗱𝗲𝘁𝗲𝗰𝘁𝗲𝗱 𝗶𝗻 𝗞𝟮-𝟭𝟴𝗯'𝘀 𝗮𝘁𝗺𝗼𝘀𝗽𝗵𝗲𝗿𝗲.

K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.

Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).

🔭🧪🪐 #exoplanet

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John Forbes @redshiftless.bsky.social · Apr 15

New paper!

High-order epicyclic description of orbits in spherically-symmetric potentials (plus vertical oscillations in a disk).

My love of epicycles is so notorious that the postgraduates made this meme

An image of Claudius Ptolemy, overlaid with a bust of Ptolemy in the outline of a heart. The bust has a thought bubble with the word epicycle. Several pink hearts as well as a diagram of the motions of planets in a geocentric epicycle+defferent system are also shown. Overlaid in several bold fonts are the words “RIP claudius ptolemy you wouldve loved john forbes :(“

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John Forbes @redshiftless.bsky.social · Apr 10

"Same as yours - weird billionaire" would work surprisingly frequently as an answer here for astronomers.

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