Ep. 49 – Reality as Seen Through The Lens of Time

The hosts record from different days on opposite sides of the Earth, discussing antipodes, the physics of traveling through the center of the Earth, Dennis' house got shot, cars in Europe and Australia, US Democratic Primaries, fashion industry faux pas, and Australian bars.

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In reality, there are two reasons gravity trains do not exist. First, a lengthy transit distance would pierce the Earth’s mantle and traverse a region where rock is more fluid than solid. No materials are known that would withstand the tremendous heat and pressure in the inner core. Temperature is estimated as 5,700 K (5,430 °C; 9,800 °F), and pressure as high as about 330 to 360 gigapascals (3,300,000 to 3,600,000 atm). Secondly, frictional losses would be significant. Rolling friction losses could be reduced by using a magnetically levitated train. However, unless all air is evacuated from the tunnel, frictional losses due to air resistance would render the gravity train unusable. Evacuating the atmosphere to make it a vactrain would eliminate this drag but would require additional power. Such objections would not apply for solid planets and moons that do not have an atmosphere.