Episode Details

How do distant galaxies form? If you have two distant clouds of hydrogen, why does one turn into a star and another doesn’t? To find out, Dr. Charles Liu and co-host Allen Liu welcome Dr. Erika Hamden, Professor of Astrophysics at the University of Arizona. If Erika looks familiar, that might be because her TED Talk or “New Frontiers,” the TV show she hosts on Arizona Public Media.

As always, though, we start off with the day’s joyfully cool cosmic thing, Artemis II, our first manned mission around the moon since 1972. Chuck, Allen and Erika share their excitement watching the mission, and especially the landing, while we watch the “only good video of the moon ever taken with a phone” that Reid Wiseman shot on his iPhone.

Dr. Hamden tells us about her research into how distant stars and galaxies form. To fill in the blanks of this cosmic puzzle, she observes hydrogen in its elemental or molecular form – not looking at the stars themselves, but the emissions from hydrogen atoms. You’ll learn about star formation in our galaxy and how Erika discerns the moment that a new star “first turns on.”

Then it’s time for our first audience question. Emma B. asks, “How many galaxies are there?” Erika says that in the observable universe, it’s an outrageously large number, probably hundreds of billions or more. We take a look at the Hubble Ultra Deep Field image, which reflects a “tiny, tiny part of the sky,” where every dot except for the 3 stars is a galaxy. And that’s just the universe we can see.

Chuck asks Erika to tell us about her book, “Weird Universe: Everything We Don’t Know about Space (and why it’s important).” Professor Hamden shares her belief that anyone can understand anything if it’s explained the right way to them. She talks about a poem by Rebecca Elson called “Responsibility to Awe” and the responsibility scientists have to share the wonders of the world with everybody.

For our next audience question, Ava asks, “What is the craziest job in Astronomy that you have seen AI take over from humans?” Erika talks about using LLMs to review the digitized photographic plates of stars and the massive amount of data from the Vera Rubin Observatory, and also which activities still require human creativity.

Speaking of creativity, it turns out that before becoming an astrophysicist, Erika got a diploma at Le Cordon Bleu in London and had a career as a professional chef. She still loves to cook and shares her recipe (below) for the Swedish-style cardamom buns she shows us in the episode.

Finally, before we go, we congratulate Emily on recently being awarded a Guggenheim Fellowship. She shares some wisdom and advice she’s learned on her journey that she also tells her students, but according to her it’s a bit “cheesy” so we’ll let her tell you in the show.

If you’d like to know more about Dr. Hamden, you can keep up with her research, follow her on her social media accounts, and find out about her book by visiting her website.

We hope you enjoy this episode of The LIUniverse, and, if you do, please support us on Patreon.

Erika’s Cardamom Bun Recipe

You can find the original recipe here on Cecilia Tolone’s Substack.

Erika’s Modifications:

“My changes are that I add more milk- about 75 grams more, because American flour is drier and Tucson is especially dry! And I played around with adding chiltipin flakes (a local, very spicy pepper) to the filling to make it kind of spicy. It’s great! Finally, I use whole cardamom seeds from Penzey’s that I grind before putting in.”

Credits for Images Used in this Episode:

• Artemis II end of mission splashdown. – Credit: NASA/ Bill Ingalls.
• Artemis II astronaut Reid Wiseman’s iPhone video of