Caltech Astronomy

08/28/2026

What causes gamma-ray bursts, the most powerful explosions in the Universe? We recently hosted Caltech PhD student Delina Levine to give a presentation at Astronomy on Tap all about gamma-ray bursts. Her awesome presentation is now up on YouTube:

https://www.youtube.com/watch?v=5rdnPvzpsbk

Photos by Robb Rosenfeld.

08/27/2026

There will be a partial lunar eclipse tonight!

You'll be able to watch the shadow of the Earth pass across the Moon, partially blocking its illumination from the Sun. If you have clear skies tonight, take a look up at the Moon and see the shadow of our own planet falling across it!

For those of us on the West Coast, the eclipse takes place between 7:32 PM and 10:52 PM. No telescope or special equipment is needed, although binoculars or a telescope can provide an even better view.

For more information, including a great animation showing what to expect, check out this article from NASA:

On August 28, 2026 (the evening of the 27th in some time zones), the Moon passes into the shadow of Earth, creating a deep partial lunar eclipse. At the moment of greatest eclipse, 4:13 a.m. Univeral Time, 96.3% of the Moon's disk will be within Earth's umbra. The Americas are centrally located for....

08/26/2026

Do you like nature, dark skies, and astronomy? Join us in two weeks for the Sequoia Dark Sky Festival, September 11–13! We'll be joining the National Park Service and Sequoia Parks Conservancy for a weekend of stargazing, telescope viewing, science presentations, family activities, and more.

Caltech scientists will give public talks on asteroids, cosmology, exploding stars, and the surprising contents of “empty” space. We'll also host an Ask an Astrophysicist panel, where you can bring your questions about astronomy, physics, and space science.

The festival is free and open to the public; park entry is not included. We hope to see you there!

https://sequoiaparksconservancy.org/dark-sky-festival/

08/24/2026

Do electrons really spin?

Last week, Caltech Professor Chip Sebens joined us to explore this deceptively simple question and took us on a journey through electromagnetism, quantum mechanics, and the philosophy of physics. His presentation is now up on YouTube:

https://www.youtube.com/watch?v=J-mNufzE8sA

08/14/2026

How did astronomers discover that our Milky Way is just one of countless galaxies in the Universe? What role did the 100-inch telescope at Mount Wilson outside of LA play in this story? We recently hosted Dr. Jeff Rich from Carnegie Observatories to discuss these topics and more. His presentation is now up on YouTube: https://youtu.be/BZNGzm6SvvE

Photos by Robb Rosenfeld.

08/07/2026

Happening this weekend. See you in Lassen!

Do you like national parks and astronomy? Join us in two weeks at Lassen National Park in Northern California for a weekend of astronomy. There will be guided stargazing with telescopes, constellation tours, an astrophysicist Q&A panel, and public science presentations from NASA and Caltech scientists. In addition, Lassen NP boasts amazing trails and mountains, as well as an active volcano and geothermal features like mud pots and fumaroles. It'll be a blast! Free and open to all after entry to the park.

https://www.nps.gov/lavo/planyourvisit/ranger_led_programs.htm