John Forbes
@redshiftless.bsky.social
Astronomer in Aotearoa/New Zealand at the University of Canterbury.
Pusher of pixels, pens, arrays, and computer keys.
www.johncforbes.com
Pusher of pixels, pens, arrays, and computer keys.
www.johncforbes.com
Introducing my new service to generate retrospectives: Orpheus
December 29, 2025 at 12:45 PM
Introducing my new service to generate retrospectives: Orpheus
Bad time for it (this week), but I appreciate the sentiment!
December 24, 2025 at 1:52 AM
Bad time for it (this week), but I appreciate the sentiment!
More observations coming soon!
December 24, 2025 at 1:52 AM
More observations coming soon!
*and by last week I mean almost 2 weeks ago.
Also, special thanks to my coauthor Harvey, a then-undergrad, now recently-graduated student at UC, who had the courage to pick a risky research project and get the ball rolling!
Also, special thanks to my coauthor Harvey, a then-undergrad, now recently-graduated student at UC, who had the courage to pick a risky research project and get the ball rolling!
December 23, 2025 at 2:13 PM
*and by last week I mean almost 2 weeks ago.
Also, special thanks to my coauthor Harvey, a then-undergrad, now recently-graduated student at UC, who had the courage to pick a risky research project and get the ball rolling!
Also, special thanks to my coauthor Harvey, a then-undergrad, now recently-graduated student at UC, who had the courage to pick a risky research project and get the ball rolling!
Nice! I've been expecting to see a post like this :-)
Sorry if I missed or if it's otherwise obvious, but do you know why the chi^2 is larger for the 3I models with nonzero Delta T? Naively I would have thought since you're fitting the same data with extra flexibility chi^2 should decrease.
Sorry if I missed or if it's otherwise obvious, but do you know why the chi^2 is larger for the 3I models with nonzero Delta T? Naively I would have thought since you're fitting the same data with extra flexibility chi^2 should decrease.
December 10, 2025 at 11:42 PM
Nice! I've been expecting to see a post like this :-)
Sorry if I missed or if it's otherwise obvious, but do you know why the chi^2 is larger for the 3I models with nonzero Delta T? Naively I would have thought since you're fitting the same data with extra flexibility chi^2 should decrease.
Sorry if I missed or if it's otherwise obvious, but do you know why the chi^2 is larger for the 3I models with nonzero Delta T? Naively I would have thought since you're fitting the same data with extra flexibility chi^2 should decrease.
Age estimates seem to be north of 100 Myr for the Pleiades (ui.adsabs.harvard.edu/abs/2022A%26... ), so stegasorouses(?) wouldn't have seen it, but iguanodons might have seen it form if I'm reading everything right!
Lost Sisters Found: TESS and Gaia Reveal a Dissolving Pleiades Complex
Most star clusters dissolve into the Galaxy over tens to hundreds of millions of years after they form. While recent Gaia studies have honed our view of cluster dispersal, the exact chronology of whic...
ui.adsabs.harvard.edu
November 28, 2025 at 2:28 AM
Age estimates seem to be north of 100 Myr for the Pleiades (ui.adsabs.harvard.edu/abs/2022A%26... ), so stegasorouses(?) wouldn't have seen it, but iguanodons might have seen it form if I'm reading everything right!
Sharks are 2 galactic years old!
November 22, 2025 at 2:34 AM
Sharks are 2 galactic years old!
I think the "abundance agenda" is vague enough that some people could read it that way, but my read is that we need to build a lot of solar/batteries/transmission (to keep fossil fuels in the ground!), and a lot of old-school environmentalists are opposed to that because it involves building stuff.
November 6, 2025 at 11:21 AM
I think the "abundance agenda" is vague enough that some people could read it that way, but my read is that we need to build a lot of solar/batteries/transmission (to keep fossil fuels in the ground!), and a lot of old-school environmentalists are opposed to that because it involves building stuff.
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).
(adapted from an argument made in this paper: arxiv.org/abs/2509.04165).
September 9, 2025 at 11:55 PM
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).
(adapted from an argument made in this paper: arxiv.org/abs/2509.04165).
It is wild how many outdoor cats there are in NZ. Everyone loves the native birds, but the outdoor cat culture is really ingrained.
August 26, 2025 at 8:30 AM
It is wild how many outdoor cats there are in NZ. Everyone loves the native birds, but the outdoor cat culture is really ingrained.
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.
August 17, 2025 at 8:25 AM
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.
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!
But seriously, not a bad point!
August 4, 2025 at 5:57 AM
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!
But seriously, not a bad point!
Yeah, could be. Google has worked well for the past decade, so it feels like the end of an era.
August 4, 2025 at 4:12 AM
Yeah, could be. Google has worked well for the past decade, so it feels like the end of an era.