After the cosmic microwave background radiation was released, the Universe returned to darkness, cloaked in this clouds of primordial hydrogen and helium. Gravity pulled these vast clouds into the first stars, and then the first galaxies. This is Cosmic Dawn, and JWST will help us probe this mysterious time.
Ep. 682: Ultra-Diffuse Galaxies and Dark Matter
Astronomers first noticed the strange behaviors of rotating galaxies almost 100 years ago, suggesting there’s an invisible dark matter hold them together with gravity. Or maybe we just don’t understand how gravity works at the largest scales. Observations are much better now, and astronomers have found examples of galaxies that almost entirely made of dark matter. Does this tell us anything?
Ep. 681: Kilonovae
In 2017, astronomers detected the gravitational waves and electromagnetic radiation from colliding neutron stars. This had been long theorized as one of the causes of a certain type of gamma-ray burst. By studying the event and its afterglow, astronomers have learned a tremendous amount about the formation of the heaviest elements in the Universe.
Ep. 680: Rogue Black Holes
Last week we talked about rogue stars. This week we’re going to take things up a notch and talk about an even more extreme event. Rogue black holes. Astronomers recently discovered a supermassive black hole on an escape trajectory, leaving newly forming stars in its wake. It’s wonderful, terrible, nightmare fuel.
Ep. 679: High(per) Velocity Stars
Most stars in the Milky Way are trapped in here with us, doomed to orbit around and around and around. But a few have found a way out, an escape into the freedom of intergalactic space. How do stars reach escape velocity, never to return?
Ep. 678: World Building: Planet Formation, Growth, & Ejection
Okay sci-fi writers, today we’re going to give you a guided tour of building planets. How they form, how they grow, and how things can go horribly horribly wrong.
Ep. 677: The Answer is Always Dust
Whenever astronomers discover something surprising, the answer often turns out to be dust. Dust obscuring our view, dust changing the polarity, dust warming things up, dust cooling things down. It’s always dust. Until it isn’t.
Ep. 676: Other Things with Rings
We’ve spent a lot of time gushing about Saturn’s rings, but there are other places with ring systems. And not just Jupiter and the ice giants, but asteroids, dwarf planets, centaurs and even exoplanets. Today we’ll gush about them.
Ep. 675: Exotic Forms of Ice
Ice is ice, right? You know, what you get when water freezes. Well, maybe here on Earth. But across the Universe, water can be squeezed together at different temperatures and pressures, leading to very different structures. Today we’ll talk about the different forms that ice can take.
Ep. 674: Asteroid Early Warning Systems
The asteroid apocalypse is one of those existential crises that keep astronomers up at night. But the DART mission showed us that we can push an asteroid off its trajectory if we have enough warning. Today we’ll talk about how humanity is building early warning systems to give us time to respond to a dangerous asteroid.
Ep. 673: How to See Satellites (or Avoid Seeing Them)
If you’re in dark skies and look up, you’re certain to see a satellite. Lots of them. But how can you know which one you’re seeing, and how can you improve your chances of a sighting? Today we’ll talk about how to see satellites, or avoid seeing them.
Ep. 672: Space Debris Removal
We’ve talked about the rising problem of space junk. Okay, we know it’s an issue. So what can be done about it? Today we’ll talk about ideas to remove space junk, making sure space is open to use for the centuries to come.
Ep. 671: The Consequences to Breaking Space Laws
Last week we talked about the laws that govern space exploration. This week the rubber hits the road. What are the consequences for actually breaking these rules? Are they really going to stop anyone?
Ep. 670: Governing Space – The Outer Space Treaty of 1967
The Universe was inaccessible for most of human history, but the first tentative steps to space in the 20th century made humanity realize that science fiction was becoming science reality. New rules would have to be written to govern how we used this limitless expanse. Today we’ll talk about the Outer Space Treaty of 1967.
Ep. 669: Challenges to Dark Energy
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.
Ep. 668: The Crisis in Cosmology
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?
Ep. 667: JWST First Science Results
Astronomers came together in January to present their newest research, and not surprisingly, the Winter AAS meeting was heavy on news from JWST. What were some of the new results that were announced?
Ep. 666: Solar System References to the Underworld
Well, we did it. We made it to episode 666, an auspicious number to be sure. What can we do to celebrate this accomplishment? An episode all about things in the Universe that have been named after mythological people and places in the underworld?
Ep. 665: The Age of Reionization
The Cosmic Microwave Background Radiation tells us so much about the Universe. After that era, the Universe went dark. Then, as gas pulled together into the first stars and eventually galaxies, light returned, beginning the Age of Reionization.
Ep. 664: The First Stars
The Sun is a third generation star, polluted with the metals from long dead stars. Astronomers have also discovered second generation stars, with very low metallicity. But theories suggest there must be a first generation, with stars made from only pure hydrogen and helium. Can we ever find them?
Ep. 663: End of Year Observing Events
We generally save our stargazing suggestions for the summer, when it’s warmer in the northern hemisphere. But you’re tough, you can handle a little cold. And it’s worth it because there are some wonderful things you can see in the night sky this time of year.
Ep. 662: Looking Ahead at New and Recycled Missions
Last week we talked about the missions we’re saying goodbye to. This week, we’re going to talk about some upcoming missions to say hello to. Some are brand new ideas, others are, uh, recycled.
Ep. 661: Looking Back on the Missions That Ended
It’s always sad to say goodbye, but when we send our robotic emissaries out into the cosmos, it’s just a matter of time before they shut down. Today we’re going to say goodbye to a few missions which have reached the end of their lives. But they were very good robots.
Ep. 660: Runaway! Runaway! Escaping Stars, Planets & Small Bodies
Moons orbit planets, planets orbit stars, stars orbit within galaxies. It’s orbits all the way down. But occasionally objects can receive a powerful kick that sends them off on a journey, never to return.
Ep. 659: Clear Skies, Bright Satellites
Light pollution is a big problem, and it’s only getting worse — not just near cities but everywhere thanks to increased satellite constellations. How bad is the problem, and how can we fix it?