541: Weird Issues: Expansion Rate of the Universe Astronomy Cast 541: Weird Issues: Expansion Rate of the Universe by Fraser Cain & Dr. Pamela Gay Just when the Universe was starting to make sense, the cosmos throws a curveball at us. Astronomers have been trying to accurately measure the expansion rate of the Universe as far back as Hubble. It's been tough to nail down, and now astronomers are starting to figure out why.

540: Weird Issues: How Do (or Don't) Planets Form? Astronomy Cast 540: Weird Issues: How Do (or Don't) Planets Form? by Fraser Cain & Dr. Pamela Gay As astronomers started to discover planets orbiting other stars, they immediately realized that their expectations would need to be tossed out. Hot jupiters? Pulsars with planets? We're now decades into this task, and the Universe is continuing to surprise us.

539: Weird Issues: Why We Don't Know the Age of Saturn's Rings Astronomy Cast 539: Weird Issues: Why We Don't Know the Age of Saturn's Rings by Fraser Cain & Dr. Pamela Gay How old are Saturn's rings? They could be brand new, or they could be as ancient as the Solar System itself. Planetary scientists thought they knew the answer thanks to new data from Cassini, but new ideas are calling even that into question.

538: Asteroids: Rubble piles of the Solar System Astronomy Cast 538: Asteroids: Rubble piles of the Solar System by Fraser Cain & Dr. Pamela Gay Thanks to all the work from Hayabusa 2 and OSIRIS-REx, astronomers are getting a much better look at the smaller asteroids in the Solar System. It turns out, they're piles of  rubble... but fascinating piles of rubble. Let's talk about what we've learned so far.

537: Reusable Rocket Revolution Astronomy Cast 537: Reusable Rocket Revolution by Fraser Cain & Dr. Pamela Gay We took a hiatus this summer, but SpaceX sure didn’t, with the tests of the Starhopper prototype. Today we’re going to talk about the revolution in reusable rocketry and quest to build a fully reusable two-stage rocket.

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Astronomy Cast will be on hiatus for July and August. Don't worry, we'll be back in September, and we might just have surprises for you all along this summer! Don't forget you can still catch Pamela with Daily Space, rocket launches and specials on , and you can find all the space news and videos from Fraser at ! We usually record Astronomy Cast every Friday at 3:00 pm EDT / 12:00 pm PDT / 19:00 UTC. You can watch us live on here on , or the .

536: Everyday Relativity Astronomy Cast 536: Everyday Relativity by Fraser Cain & Dr. Pamela Gay Relativity is used in more day to day situations than you may realize. In this episode, we will count (some of) the ways. This episode is brought to you live from the All-Stars Star Party in Indian Wells, California.

535: Astronomy-Related Things To Do This Summer Astronomy Cast 535: Astronomy-Related Things To Do This Summer by Fraser Cain & Dr. Pamela Gay It's summertime, and time for our annual Astronomy Cast hiatus. But that doesn't mean that the astronomy adventure has to end. Today we'll give you some tips and tricks for astronomy summer adventures.

534: Modern South African Astronomy Astronomy Cast 534: Modern South African Astronomy by Fraser Cain & Dr. Pamela Gay You know the drill now. Last week we talked about ancient south African astronomy, and so this week we'll talk about the modern state of astronomy in the southern part of Africa, which happens to be a great place with nice dark skies and a perfect view into the heart of the galaxy.