Andrew Jaffe
@defjaf.bsky.social
Astrophysics, cosmology, Bayesian inference, parenthood, politics, rock ’n’ roll, & more. Professor at Imperial College. andrewjaffe.net He/him/his
The Random Universe—coming in November. https://yalebooks.yale.edu/book/9780300250503/the-random-universe/
The Random Universe—coming in November. https://yalebooks.yale.edu/book/9780300250503/the-random-universe/
Today in the NY Times: Lisa Lucas’ love letter to Leiden, one of the intellectual capitals of Europe.
November 12, 2025 at 10:43 AM
Today in the NY Times: Lisa Lucas’ love letter to Leiden, one of the intellectual capitals of Europe.
I talk about The Random Universe (the book, and the Universe itself) on [Sean Carroll's Mindscape. We cover epistemology, probability, quantum mechanics, cosmology and more. Sean and I were cosmology grad students at the same time, and it was a pleasure and an honour to spend time with him online.
335 | Andrew Jaffe on Models, Probability, and the Universe – Sean Carroll
www.preposterousuniverse.com
November 11, 2025 at 10:54 AM
I talk about The Random Universe (the book, and the Universe itself) on [Sean Carroll's Mindscape. We cover epistemology, probability, quantum mechanics, cosmology and more. Sean and I were cosmology grad students at the same time, and it was a pleasure and an honour to spend time with him online.
Reposted by Andrew Jaffe
in this week’s Mindscape, as @seanmcarroll.bsky.social talks with
@defjaf.bsky.social about “Models, Probability, and the Universe”, I learned that in Jaffe’s (and others’) model, the Hubble constant is 67.
kids today might be either thrilled or deflated by this value.
I myself would prefer 42.
@defjaf.bsky.social about “Models, Probability, and the Universe”, I learned that in Jaffe’s (and others’) model, the Hubble constant is 67.
kids today might be either thrilled or deflated by this value.
I myself would prefer 42.
November 10, 2025 at 2:02 PM
in this week’s Mindscape, as @seanmcarroll.bsky.social talks with
@defjaf.bsky.social about “Models, Probability, and the Universe”, I learned that in Jaffe’s (and others’) model, the Hubble constant is 67.
kids today might be either thrilled or deflated by this value.
I myself would prefer 42.
@defjaf.bsky.social about “Models, Probability, and the Universe”, I learned that in Jaffe’s (and others’) model, the Hubble constant is 67.
kids today might be either thrilled or deflated by this value.
I myself would prefer 42.
The Random Universe isn’t out until tomorrow (November 11), but the Kindle edition is on sale in both the US and in the UK. (And if you look very carefully, you’ll see that it has broken into the top 100 UK cosmology bestsellers…)
November 10, 2025 at 12:55 PM
The Random Universe isn’t out until tomorrow (November 11), but the Kindle edition is on sale in both the US and in the UK. (And if you look very carefully, you’ll see that it has broken into the top 100 UK cosmology bestsellers…)
Unboxing The Random Universe youtube.com/shorts/tvQJh...
Unboxing The Random Universe
YouTube video by Andrew Jaffe
youtube.com
November 5, 2025 at 6:23 PM
Unboxing The Random Universe youtube.com/shorts/tvQJh...
Unboxing my book, The Random Universe
The Random Universe
An award-winning astrophysicist looks at how the understanding of uncertainty and randomness has led to breakthroughs in our knowledge of the cosmos All o...
yalebooks.yale.edu
November 5, 2025 at 5:17 PM
Unboxing my book, The Random Universe
Reposted by Andrew Jaffe
What happens when science takes a backseat in government policy? A critical examination from @defjaf.bsky.social .
The Trump Administration's Contempt for Science - Yale University Press
Andrew H. Jaffe— The biggest economy in the world has decided that science is not a priority, barely worth supporting. This is the arrogance of American leaders unable or unwilling... READ MORE
yalebooks.yale.edu
October 30, 2025 at 9:31 PM
What happens when science takes a backseat in government policy? A critical examination from @defjaf.bsky.social .
The Random Universe isn’t due out until November 11, but not only can you pre-order your copy today, you can also download a free sample from the e-book. (Similar on Amazon UK and Apple Books — though it’s even better if you buy your hardcopy from an independent bookseller!)
October 27, 2025 at 4:17 PM
The Random Universe isn’t due out until November 11, but not only can you pre-order your copy today, you can also download a free sample from the e-book. (Similar on Amazon UK and Apple Books — though it’s even better if you buy your hardcopy from an independent bookseller!)
The clocks went back an hour here in London overnight—summertime is over. I suppose I’m happy for the extra time to rest (though in fact I didn’t sleep very well last night) but not looking forward to six months of early darkness.
October 26, 2025 at 6:44 AM
The clocks went back an hour here in London overnight—summertime is over. I suppose I’m happy for the extra time to rest (though in fact I didn’t sleep very well last night) but not looking forward to six months of early darkness.
The Trump Administration’s Contempt for Science. (Thanks to the Yale University Press for letting me express my opinions.)
The Trump Administration's Contempt for Science - Yale University Press
Andrew H. Jaffe— The biggest economy in the world has decided that science is not a priority, barely worth supporting. This is the arrogance of American leaders unable or unwilling... READ MORE
yalebooks.yale.edu
October 24, 2025 at 4:17 PM
The Trump Administration’s Contempt for Science. (Thanks to the Yale University Press for letting me express my opinions.)
Apparently I am the subject of an unauthorised biopic.
October 20, 2025 at 11:23 AM
Apparently I am the subject of an unauthorised biopic.
Lots of fun recording an episode of the Mindscape podcast with Sean Carroll. Should appear on November 10, just before the release of The Random Universe.
October 20, 2025 at 10:04 AM
Lots of fun recording an episode of the Mindscape podcast with Sean Carroll. Should appear on November 10, just before the release of The Random Universe.
Surprised that Taylor needs to promote her latest with an A4 poster at the Imperial College elevators (lifts).
October 3, 2025 at 5:29 PM
Surprised that Taylor needs to promote her latest with an A4 poster at the Imperial College elevators (lifts).
Last year was a sabbatical, so today I’ve got my first proper teaching in a full year and a half — a two-hour lecture to start my Information Theory course.
Feeling a bit nervous!
Feeling a bit nervous!
October 3, 2025 at 12:24 PM
Last year was a sabbatical, so today I’ve got my first proper teaching in a full year and a half — a two-hour lecture to start my Information Theory course.
Feeling a bit nervous!
Feeling a bit nervous!
R.I.P. George Smoot, experimental cosmologist, Nobel prize winner and one of the discoverers of primordial fluctuations in the cosmic microwave background, a colleague and mentor back when I was a postdoc in Berkeley, always curious and enthusiastic.
September 26, 2025 at 9:40 PM
R.I.P. George Smoot, experimental cosmologist, Nobel prize winner and one of the discoverers of primordial fluctuations in the cosmic microwave background, a colleague and mentor back when I was a postdoc in Berkeley, always curious and enthusiastic.
macOS Tahoe/Safari complaint: in sidebar showing Tab Groups, current group shows tab list as if the disclosure triangle clicked.
Bad enough. But worse: old group in the sidebar stays open even when I click to a new one!
This seems so wrong that there must be a setting — but I couldn’t find it.
Bad enough. But worse: old group in the sidebar stays open even when I click to a new one!
This seems so wrong that there must be a setting — but I couldn’t find it.
September 22, 2025 at 10:35 AM
macOS Tahoe/Safari complaint: in sidebar showing Tab Groups, current group shows tab list as if the disclosure triangle clicked.
Bad enough. But worse: old group in the sidebar stays open even when I click to a new one!
This seems so wrong that there must be a setting — but I couldn’t find it.
Bad enough. But worse: old group in the sidebar stays open even when I click to a new one!
This seems so wrong that there must be a setting — but I couldn’t find it.
This seems like a whole mess of bugs. (Trying to update to macOS 26 Tahoe. Perhaps this is telling me it’s a bad idea?…)
> `PASSWORD_ALERT_TITLE_WITH_USERNAME_OSX_REBRAND_SERVICE_ICLOUD`
> `PASSWORD_ALERT_MESSAGE_WITH_USERNAME_OSX_REBRAND`
> `FOL... https://andrewjaffe.net/microblog/2025/09/1062/
> `PASSWORD_ALERT_TITLE_WITH_USERNAME_OSX_REBRAND_SERVICE_ICLOUD`
> `PASSWORD_ALERT_MESSAGE_WITH_USERNAME_OSX_REBRAND`
> `FOL... https://andrewjaffe.net/microblog/2025/09/1062/
September 16, 2025 at 8:08 AM
This seems like a whole mess of bugs. (Trying to update to macOS 26 Tahoe. Perhaps this is telling me it’s a bad idea?…)
> `PASSWORD_ALERT_TITLE_WITH_USERNAME_OSX_REBRAND_SERVICE_ICLOUD`
> `PASSWORD_ALERT_MESSAGE_WITH_USERNAME_OSX_REBRAND`
> `FOL... https://andrewjaffe.net/microblog/2025/09/1062/
> `PASSWORD_ALERT_TITLE_WITH_USERNAME_OSX_REBRAND_SERVICE_ICLOUD`
> `PASSWORD_ALERT_MESSAGE_WITH_USERNAME_OSX_REBRAND`
> `FOL... https://andrewjaffe.net/microblog/2025/09/1062/
Yesterday, someone walked into the café I was sitting in wearing a Primitives t-shirt. Today, their wonderful “Crash” came on my random streaming mix, so it seems appropriate to share one of the great pop songs of all time.
September 12, 2025 at 10:30 AM
Yesterday, someone walked into the café I was sitting in wearing a Primitives t-shirt. Today, their wonderful “Crash” came on my random streaming mix, so it seems appropriate to share one of the great pop songs of all time.
The amazing Lisa Lucas’ latest for the NY Times, on hunting the autumn leaves in Japan — 3 Days of ‘Momijigari’: Experiencing Japan’s Fiery Autumnal Foliage.
September 8, 2025 at 1:04 PM
The amazing Lisa Lucas’ latest for the NY Times, on hunting the autumn leaves in Japan — 3 Days of ‘Momijigari’: Experiencing Japan’s Fiery Autumnal Foliage.
You can pre-order The Random Universe, get a 7% discount, and support local bookstores, all at the same time.
September 7, 2025 at 9:06 AM
You can pre-order The Random Universe, get a 7% discount, and support local bookstores, all at the same time.
Back — home — to London after 386 days away.
August 21, 2025 at 5:00 PM
Back — home — to London after 386 days away.