A new #CosmicDistanceLadder post to mark the summer solstice, on how astronomical measurements, from the time of Eratosthenes to the modern day, rely on the tireless (and often unsung) efforts of many careful and precise data collectors. www.instagram.com/p/DLG6a_WIWyb

A new #CosmicDistanceLadder post on how the distance ladder can also be used to measure cosmic durations, as well as cosmic distances. www.instagram.com/p/DJ2ra2soG4j

After 200 days, we finally have 100% completion on the primary goal of the Equational Theories Project to formally resolve >22 million implications between 4694 equational laws, using modern proof assistants, collaboration platforms, and automated theorem provers. teorth.github.io/equational_t...

A new #CosmicDistanceLadder post, on intriguing hints from the DESI survey data that suggests that the cosmological constant (aka "dark energy) might not, in fact, be constant after all. www.instagram.com/p/DIP0yy5oDUu

A new #CosmicDistanceLadder post on why lunar and solar eclipses tend to come in pairs (for instance, the solar eclipse next week is paired with the lunar eclipse from last week). www.instagram.com/p/DHkS3EcA40L

A new #CosmicDistanceLadder post, on how the recent lunar eclipse from the vantage point of the Earth becomes a solar eclipse from the vantage point of the Moon: www.instagram.com/p/DHR1tuWonDR/

A new post on my #CosmicDistanceLadder Instagram with Tanya Klowden on the parallels (but also differences) between ancient Greek and ancient Indian astronomy. www.instagram.com/p/DGzJs02AbBA

A brief update on my #CosmicDistanceLadder instagram with Tanya on the fires that have affected (one of our) home cities. (But the sky is much, much bluer today.) www.instagram.com/p/DEyx7o_OFLz

A #CosmicDistanceLadder on how Christmas in Australia is inverted in many ways from Christmas in the Northern hemisphere, and how the parallax differences were once important in climbing that distance ladder. www.instagram.com/p/DEExnvvRkCQ

A new
#CosmicDistanceLadder
post on the winter/summer solstice in the Northern/Southern hemisphere yesterday: www.instagram.com/p/DD1c47nIKJ2 (One can also refer to this solstice as the Southern solstice - the time of year when the Sun is at its southernmost, regardless where one is on the Earth.)

Tanya Klowden and I visited the Getty Museum to see some scientific and artistic exhibits relevant (mostly from the ancient Greek, Arab, and medieval eras) to our Cosmic Distance www.instagram.com/p/DDgGAyEI5eR/

A new post by my co-author Tanya Klowden on our "Cosmic distance ladder" instagram, on the constellations on the ecliptic (most familiar to western astrology as the signs of the Zodiac), as viewed by native Americans prior to European colonization. www.instagram.com/p/DC8gvXXxtfw

Tanya Klowden and I have set up an instagram to record various #astronomy stories we have gathered during the process of writing a forthcoming book on the cosmic distance ladder. Our latest post, on the "mini-moon" that briefly visited our neighborhood, is now up: www.instagram.com/p/DC08k17xZqB