This week, I sat down with Julia Brodsky, astrophysicist, educator, former NASA astronaut trainer, founder and CEO of the Art of Inquiry, and researcher with the Blue Marble Space Institute of Science. She’s also a co-founder of Earthlings Hub, an education and outreach organization that conducts astronomy and STEM education programs for orphans, refugee children, and families in Ukraine.

The series continues with the latest stop in the Solar System: Mercury! Hold up, that can’t be right! And yet, it is. Contrary to popular opinion, humans could actually live on Mercury, the closest planet to our Sun. Granted, it won’t exactly be a cakewalk. In addition to being an airless body (i.e., no atmosphere to speak of), Mercury is exposed to almost seven times as much radiation as Earth.

And because of its slow rotation and rapid orbit, surface temperatures range from hot enough to melt lead to cryogenically freezing! But with the right know-how, technology, and strategies, we could build a thriving outpost of civilization and economy on Mrcury based on the export of mineral wealth and energy, as well as art and ideas!

The idea has been explored in science fiction and scientific literature alike. And assuming there are enough people adventurous enough to settle there, there’d be a new branch of humanity known as “Hermeans.” Follow the links below to learn more.

Where to Listen:

• Simplecast
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This week’s topic is near and dear to my heart (I know, when aren’t they?). But this one is especially so since so much depends on it. Around the world today, space agencies and commercial space entities are developing nuclear propulsion systems. These systems come in the form of Nuclear-Thermal (NTP), Nuclear-Electric (NEP), and Bimodal Nuclear Propulsion (BNP) – where both methods are used by a spacecraft.

This week, I got into one of the more intriguing aspects of astrobiology – the search for life in the cosmos! Right now, all of our astrobiology efforts are focused on Mars, the most “habitable” planet (by our standards) beyond Earth. But what of the icy moons that orbit Jupiter, Saturn, and beyond? For decades, scientists have speculated that moons orbiting gas giants beyond the “Frost Line” could have warm-water oceans that could support life.

These oceans result from the gravitational pull of the gas giants they orbit, causing tidal flexing in their interiors. This, it was theorized, would lead to hydrothermal activity at the core-mantle boundary, where the icy outer shell meets the rocky and metallic core. The energy this released would maintain a liquid-water ocean rich in the chemical elements we associate with life.

The theory emerged by the 1970s after scientists got a good look at some of Jupiter’s largest moons – Europa and Ganymede – which showed evidence of resurfacing, plume activity, and their interactions with Jupiter”s magnetic field. In recent years, the list of “Ocean Worlds” has expanded to include moons like Titan, Enceladus, Dione, Ariel, Umbriel, Titania, Oberon, Triton, Charon, and even Pluto!

In all cases, these bodies have geological activity or sufficient nuclear elements (which decay to produce heat) to maintain liquid water in their interiors. The plethora of “Ocean Worlds” in our Solar System also has implications for the search for life in extrasolar systems. After all, if icy satellites in our outer Solar System could support life, then similar bodies are sure to exist out there (in abundance). Check it out below!

Where to Listen:

• Simplecast
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This week, I sat down with NASA astronomer and exoplanet researcher Dr. Charles Beichman, the Executive Director of the NASA Exoplanet Science Institute (NExScI) at Caltech. He’s an esteemed scientist who has spent decades searching for exoplanets and led several path-finding missions. These include the Space Interferometer Mission (SIM), the Infrared Astronomical Satellite (IRAS), the Spitzer Space Telescope, and the 2 Micron All Sky Survey (2MASS).

One could say that he was looking for exoplanets before it was “cool.” Suffice it to say, the man has some very interesting stories. Very soon, he and a team of astronomers will be using the James Webb Space Telescope (JWST) to observe Alpha Centauri, where they hope to find the first definitive proof of exoplanets in that system. I think I speak for everyone when I wish him and his colleagues the best of luck!

Where to Listen:

• Simplecast
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This week’s episode focuses on the life and times of Nicolaus Copernicus, the famed Renaissance Polish astronomer who proposed the heliocentric model of the Universe. The details of this model were presented in his magnum opus, On the Revolutions of the Heavenly Spheres, which Copernicus had published in 1543 when he was on his deathbed. While Copernicus is a household name and the basics of his model are well-known, the story of how he came to his grand realization is less well-known.

The heliocentric model was inspired by thousands of years of observations and calculations by astronomers. These included several pre-Socratic Greek texts lost to Europeans (but preserved by Muslim scholars) and scholars from West Asia, Iran, India, and Al-Andalus (Spain before the Reconquista). These sources contradicted the prevailing models of Aristotle and Ptolemy, both of whom were considered canon in Europe and Eurasia.

By synthesizing these observations with his own calculations, Copernicus showed how Earth and the other planets orbited the Sun, how the Moon orbited Earth, and how Earth rotated. In short, he synthesized and crystallized one of the most profound scientific discoveries ever made, one that was thousands of years in the making. And in so doing, he forever revolutionized our understanding of the cosmos and our place in it.

In fact, his observation that the Sun was NOT at the center of the Universe began a long process where humans began to realize that neither they nor Earth were unique in the cosmos. As Sagan put it: “One of the distinctions and triumphs of the advance of science has been the deprovincialization of our worldview.” Because of Copernicus’s role in this, the scientific axiom that states that humanity is NOT in a special or privileged position to view the cosmos is known as the Copernican Principle.

Where to Listen:

• Simplecast
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This week’s guest was astrophysicist, science communicator, and author Ethan Siegel. Ethan has been a professor of astrophysics at multiple universities, a senior contributor to Forbes magazine (ever heard of it?), and their chief science writer. He is also the producer of Starts with a Bang, a podcast and column where he talks about the Big Bang and other big questions related to cosmology.

His books include Trekology, which explores the technical aspects of the famous Star Trek franchise; Beyond the Galaxy, an examination of humanity’s growing awareness of the Universe; and the upcoming Encyclopaedia Cosmologica, a richly-illustrated and plainly-explained origin story about the cosmos.

During our chat, we got into multiple topics, including the greatest mysteries facing astronomers and cosmologists today, the James Webb naming controversy, and what makes astrophysics and science communication so exciting! Take a listen and be sure to check out Ethan’s podcast, articles, and websites.

Where to Listen:

• Spotify
• Apple Podcasts
• Amazon Music
• Simplecast