#745: How We Know if Asteroids Will Attack

New asteroids are found every day, and every day we learn that those asteroids don’t have any murderous intentions. But how do we learn that?

Our Hosts

Fraser Cain
Universe Today

Dr. Pamela Gay
CosmoQuest

Production by

  • Richard Drumm, Audio Engineer
  • Ally Pelphrey, Video Engineer

18 Seasons

700+ Episodes

2018 Winner Parsec Award

Ep. 702: Moonshot 2024 – Go or No Go?

Ep. 702: Moonshot 2024 – Go or No Go?

With Artemis 1 completing its robotic flight around the Moon, we know that the SLS works. Next comes Artemis 2, with a crew of astronauts flying past the Moon. If that’s successful, we could see humans set foot on the Moon in December 2025. But there is a long list of challenges to consider that could delay things considerably. Go or no go for launch?

Ep. 700: Things We Got Wrong

Ep. 700: Things We Got Wrong

Astronomers talk about all the amazing discoveries they’re making but sometimes, it turns out, they were wrong. After decades and centuries of discoveries, how have they changed their minds?

Recent Episodes

Ep. 530: Astronomy of the Andes – Then and Now Pt. 2

South America, especially the Atacama Desert in Chile has become one of the best places in the world to put a telescope. It's dry, high, and the nights are clear. Today we'll talk about the monster telescopes already in operation in this region, and the big ones...

Ep. 529: Astronomy of the Andes – Then and Now Pt. 1

The Andes mountains in South America are a hotspot of astronomy today, but ancient peoples knew it was a great place for astronomy and lived their lives in tune with the night sky. Today we'll learn all about what they knew, and how they mapped the movements of the...

Ep. 528: Modern Astronomy of the American Southwest

Last week we talked about the ancient astronomy of the American Southwest. But this is actually Pamela's stomping grounds, and she's spent many a night perched atop mountains in this region staring in the night sky with gigantic telescopes. How does astronomy get done...

Ep. 527: Ancient Astronomy of the American Southwest

Ancient peoples had no light pollution, and they knew the night skies very well. In fact, they depends on them to know when to plant and when to harvest. Today Pamela talks about the archeoastronomical sites of the American Southwest. In this episode we mentioned...

Ep. 526: Event Horizon Telescope and the Black Hole at M87

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. In this episode we mentioned donations and tours. Click to learn more! Download MP3| Download Raw Show with Q&A|...

Ep. 525: 100 Years of the International Astronomical Union

Even though they might be scattered around our planet, astronomers have way to come together to work out issues that face their entire field of study. It's called the International Astronomical Union, and they're the ones who work out the new names for stars, and...

Ep. 524: Judging Age & Origins, part 3 – Beyond Our System

We learned how to figure out the ages of objects in the Solar System, now we push out into the deeper Universe. What about stars, galaxies, and even the Universe itself? How old is it? This episode is part 3 of a series.In this episode we mentioned donations and...

Ep. 523: Judging Age & Origins, Pt. 2 Across the Solar System

Today we push our aging curiosity out into the Solar System to ask that simple question: how old is it and how do we know? What techniques do astronomers use to age various objects and regions in the Solar System? This is part two of a series. In this episode we...

Bonus Episode: Dust with Dr. Paul Sutter

Recorded during the Astrotour to Costa Rica, Fraser talks to Dr. Paul Matt Sutter about the nature of dust and BICEP 2's claim of discovering primordial gravitational waves. In this episode we mentioned donations and tours. Click to learn more! Download MP3| Download...

Ep. 522: Judging Age & Origins, part 1 – Earth Rocks

People always want to know how old everything is. And more specifically, they want to know how we know how old everything is. Well, here at Astronomy Cast, it's our job to tell you now only what we know, but how we know what we know. And today we'll begin a series on...

Ep. 521: The Deep Space Network

We always focus on the missions, but there's an important glue that holds the whole system together. The Deep Space Network. Today we're going to talk about how this system works and how it communicates with all the spacecraft out there in the Solar System. In this...

Ep. 520: Transients: What They Are and Why They Matter, Part 2

This is our second episode in a two part series where we look at Transients in astronomy. In last week's episode, we talked about things that change here in our own Solar System. Now we'll talk about everything else in the Milky Way and beyond.In this episode we...

Ep. 519: Transients: What They Are and Why They Matter

Astronomers have found that sometimes the Universe changes. Things move, things explode, things get brighter or dimmer. In fact, knowing this has helped astronomers discover some very important aspects of the Universe. Today we begin a two part series on Transients...

Ep. 518: When the Universe tried to Declare War

We always say the Universe is trying to kill us. But there was this one time, when the Universe used our own fear of nuclear attack against us, nearly setting off a global nuclear war. Nice try Universe, we're on to you now. In this episode we mentioned donations and...

Ep. 517: Fritz Zwicky and the Zwicky Transient Facility

One of the most influential astronomers in the 20th Century was Fritz Zwicky. He had his hand in the discovery of dark matter, gravitational lensing, supernovae and neutron stars. And he also worked on a few more controversial ideas like, uh, tired light. Let's learn...

Ep. 516: Polar Vortices

It's cold right now. Okay, fine, here on Vancouver Island, it's actually pretty warm. But for the rest of Canada and big parts of the US, it's terrifyingly cold. Colder than Mars or the North Pole cold. This is all thanks to the break up of the polar vortex. What are...

Ep. 515: Space Radiation

Space is a hostile environment in so many ways. But one of its worst features is the various kinds of radiation you can find. When astronauts go back beyond the protective environment of the Earth's magnetosphere, what are the various kinds of radiation they'll...

Ep. 514: Planetary Protection Protocols

As we send rovers and landers to other worlds, we have to think about the tiny microbial astronauts we're sending along with us. In fact, NASA is so concerned about infecting other worlds that it has established the planetary protection protocols. Just to be safe. In...

Ep. 513: Stellar Fusion

The Sun. It's a big ball of fire, right? Apparently not. In fact, what's going on inside of the Sun took us some time and knowledge of physics to finally figure out: stellar fusion. Let's talk about the different kinds of fusion, and how we're trying to adapt it to...

Ep. 512: Direct Imaging of Exoplanets

Finding planets is old news, we now know of thousands and thousands of the places. But the terrible irony is that we can only see a fraction of the planets out there using the traditional methods of radial velocity and transits. But the new telescopes will take things...