Fraser Cain
Universe Today
Dr. Pamela Gay
CosmoQuest
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.
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?
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.
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.
Recent Episodes
Astronomers rely on the optics of their instruments, and there are some basic limits that you just can't avoid. Whatever we look at is distorted by the optics, in fact, a basic property of light means that we'll never get perfect optics. Here's why we can't "magnify...
When he wasn't puzzling the mystery of alien civilizations, Enrico Fermi was splitting atoms. He realized that when atoms were split, the neutrons released could go on and split other atoms, creating a chain reaction - and the most powerful weapons ever devised....
Physicists knew the interior of the atom contained protons, neutrons and electrons, but they didn't understand exactly how they were organized. It took Ernest Rutherford to uncover our modern understanding. Download the show [MP3] | Jump to Shownotes | Jump to...
At the end of the 19th century, physicists were finally beginning to understand the nature of matter itself, including the discovery of electrons - tiny particles of negative charge that surround the nucleus. Here's how J.J. Thompson separated the electrons from their...
Evolution explains how life adapts and evolves over eons. But how did life originate? Chemists Miller and Urey put the raw chemicals of life into a solution, applied an electric charge, and created amino acids - the building blocks of life. Download the show [MP3] |...
With the discovery of water ice in so many locations in the Solar System, scientists are hopeful in the search for life on other worlds. Guest Morgan Rehnberg returns to Astronomy Cast to explain the best places we should be looking for life. Download the show [MP3] |...
In the world of quantum mechanics, particles behave in discreet ways. One breakthrough experiment was the Stern-Gerlach Experiment, performed in 1922. They passed silver atoms through a magnetic field and watched how the spin of the atoms caused the particles to...
Antoine Henri Becquerel discovered radioactivity completely by accident when he exposed a chunk of uranium to a photographic plate. This opened up a whole new field of research to uncover the source of the mysterious energy. Download the show [MP3] | Jump to Shownotes...
In 1909 Robert Millikan devised an ingenious experiment to figure out the charge of an electron using a drop of oil. Let's talk about this Nobel Prize winning experiment. Download the show [MP3] | Jump to Shownotes | Jump to Transcript This episode is sponsored...
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...
One of the most amazing implications of Einstein's relativity is the fact that the inertial mass of an object depends on its velocity. That sounds like a difficult thing to test, but that's exactly what happened through a series of experiments performed by Kaufmann,...
Light is tricky stuff, and it took scientists hundreds of years to puzzle out what this stuff is. But they poked and prodded at it with many clever experiments to try to measure its speed, motion and interaction with the rest of the Universe. For example, the Fizeau...
Waves move through a medium, like water or air. So it seemed logical to search for a medium that light waves move through. The Michelson-Morley Experiment attempted to search for this medium, known as the "luminiferous aether". The experiment gave a negative result,...
We've spent the last few weeks talking about different ways astronomers are searching for exoplanets. But now we reach the most exciting part of this story: actually imaging these planets directly. Today we're going to talk about the work NASA's Spitzer Space...
Almost all the planet hunting has been done from space. But there's a new instrument installed on the European Southern Observatory's 3.6 meter telescope called the High Accuracy Radial velocity Planet Searcher which has already turned up 130 planets. Is this the...
The European Gaia spacecraft launched about a year ago with the ambitious goal of mapping one billion years in the Milky Way. That's 1% of all the stars in our entire galaxy, which it will monitor about 70 times over its 5-year mission. If all goes well, we'll learn...
Before NASA's Kepler mission searched for exoplanets using the transit method, there was the European COROT mission, launched in 2006. It was sent to search for planets with short orbital periods and find solar oscillations in stars. It was an incredibly productive...
Where on Earth did our water come from. Well, obviously not from Earth, of course, but from space. But did it come from comets, or did the water form naturally right here in the Solar System, and the Earth just scooped it up? Download the show [MP3] | Jump to...
It hard to think of a more influential modern planetary scientist than Carolyn Porco, the leader of the imaging team for NASA's Cassini mission exploring Saturn. But before Cassini, Porco was involved in Voyager missions, and she'll be leading up the imaging team for...
Maria Zuber is one of the hardest working scientists in planetary science, being a part of six different space missions to explore the Solar System. Currently, she's the lead investigator for NASA's GRAIL mission. Download the show [MP3] | Jump to Shownotes | Jump to...