It’s been over 20 years since astronomers first discovered that the expansion of the Universe is accelerating thanks to dark energy. And in these decades, astronomers still don’t have much evidence for what could be causing the increased expansion rate. Maybe there’s something else going on to explain it.
Astronomers have made extremely accurate measurements of the expansion rate of the Universe and come up with different results. And the error bars for the observations don’t overlap, so there’s something strange going on. What’s the answer and how can the Crisis in Cosmology be resolved?
As astronomers look out across the Universe, they see various objects spewing jets of material light years into space. What causes these jets, and what impact do they have on the Universe.
Have you ever wanted to be a time traveler? Good news! You’re time traveling right now. Into the future at one second per second. Too long? Don’t want to wait? Good news, Einstein’s got you covered. Today, let’s talk about the weird world of time dilation.
This year’s Nobel Prize in Physics was awarded to three brilliant researchers who worked out some of the secrets of black holes. Today we’re going to talk about the chain of discoveries that led to this award.
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.
Today, of course, we’re going to talk about the announcement from the Event Horizon Telescope and the first photograph of a black hole’s event horizon.
Last week, we gave you an update in particle physics. This week it’s time to see what’s new in the world of dark matter. Spoiler alert, we still have no idea what it is, but maybe a few more ideas for what it isn’t.
At the turn of the 20th Century, Einstein’s theory of relativity stunned the physics world, but the experimental evidence needed to be found. And so, in 1919, another respected astronomer, Arthur Eddington, observed the deflection of stars by the gravity of the Sun during a solar eclipse. Here’s the story of that famous experiment.
Today, time rules our lives. We live each day with the moments broken up into hours, minutes and seconds. We never seem to have enough time. But can you imagine not being able to tell time at all, where the movements of the Sun and the stars was the only way to know what time it was? Let’s learn about the history of time, methods of telling time, and Einstein’s historic discovery that time isn’t as fixed as we thought it was.
Another week, another roundup of your questions. This week listeners asked: will reaching light speed destroy the Universe? When is Andromeda going to look really, really cool with the unaided eye? Why didn’t dark matter all turn into black holes? And there’s even more. If you’ve got a question for the Astronomy Cast team, please email it in to info@astronomycast.com and we’ll try to tackle it for a future show.
We’re going to return back to a long series of episodes we like to call: Radiation that Will Turn You Into a Superhero. This time we’re going to look at cosmic rays, which everyone knows made the Fantastic Four. These high-energy particles are streaming from the Sun and even intergalactic space, and do a wonderful job of destroying our DNA, giving us radiation sickness, and maybe (hopefully!) turning us into superheroes.
We interrupt this tour through the solar system to bring you a special show to deal with one of our most complicated subjects: the big bang. Specifically, how it’s possible that the universe could have expanded faster than the speed of light. The theory is called the inflationary theory, and the evidence is mounting to support it. Einstein said that nothing can move faster than the speed of light, and yet astronomers think the universe expanded from a microscopic spec to become larger than the solar system, in a fraction of a second.
If you remember way back to Episode 9, we covered Einstein’s Theory of Special Relativity. Well, that’s only half of the relativity picture. The great scientist made an even more profound impact on physics with his theory of general relativity, replacing Newton with a better model for gravity.
It’s all relative. How many times have you heard that? Well, when you’re traveling close to the speed of light, everything really is relative; especially the passage of time. This week, Fraser and Pamela give you the skinny on Einstein’s Special Theory of Relativity. After listening to a few thought experiments, you too should be able to wrap your head around this amazing theory.