Caltech Astronomy

09/07/2026

We'll be in Nevada this weekend for the Great Basin Astronomy Festival, featuring science presentations, astrophotography, and telescopes in some of the darkest skies in the USA. Join us for astronomy as well as mountains, trails, and the oldest living trees in the world! Event is in coordination with Great Basin National Park, and everything including entry to the park is free!

09/04/2026

What happens when a star ventures too close to a supermassive black hole? How can a black hole's gravity literally tear a star apart, and what happens to the stellar debris afterward? We recently hosted black hole researcher Xiaoshan Huang to discuss these phenomena, known as Tidal Disruption Events, at a recent Astronomy on Tap. Her presentation is now up on Youtube:

https://www.youtube.com/watch?v=eMruXJUbHNo

Photos by Robb Rosenfeld.

09/02/2026

Come look through a telescope under some of the darkest skies in the USA! Join us next week at Great Basin National Park in eastern Nevada for the Great Basin Astronomy Festival, September 10–12.

We'll be joining the National Park Service for three days of stargazing, telescope viewing, science presentations, astrophotography, family activities, and more. We'll even host an Astronomy on Tap in the park!

Caltech scientists will give public talks on galaxies, cosmic fireworks, black holes, and alien worlds, and we'll be operating solar telescopes throughout the day. When you're not looking through a telescope, Great Basin has some spectacular hiking: visit ancient bristlecone pines that have lived for thousands of years, explore Lehman Caves, or climb 13,000-foot Wheeler Peak, the second-highest mountain in Nevada.

The festival is free and open to the public, and there's no entrance fee for Great Basin National Park. We hope to see you there!

https://www.nps.gov/grba/planyourvisit/great-basin-astronomy-festival.htm

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