Travelers in the Night Eps. 367 & 368: Moons of Florence & Roving Venus

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:22Dr. Lance Benner of NASA's Jet Propulsion Laboratory headed up a team of scientists who used the 70-meter antenna at NASA's Goldstone Deep Space Communications Complex to bounce radar beams off the asteroid Florence as it made a close approach to Earth in September of 2017. The radar images these researchers obtained reveal that Florence consists of a 2.8-mile diameter primary asteroid

0:53which is orbited by two small moons. Florence's two satellites appear to be between 300 and 1,000 feet in diameter and orbit the main asteroid in about 8 and 24 hours, respectively. Florence is rare since there are only two other triple asteroid systems among the 16,000 Earth-approaching asteroids which asteroid hunters have discovered. We would know more about Florence if Hurricane Irma had not prevented astronomers

1:25from using the giant Arecibo radar dish in Puerto Rico to study it. Our curiosity will have to wait since Florence will not come very close again until September 2, 2057. Like the other triple Earth-approaching asteroid systems, the main asteroid in the Florence system rotates fairly quickly, once about every 141 minutes. Perhaps it was spun up to this speed by a collision or by the effect of sunlight over a very long period of time.

1:58Either way, such a spin-up could cause an asteroid to break up into several pieces producing a large asteroid orbited by two small moons. For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org program 399 for more information.

2:23Venus and Earth are similar in size, composition, density, and mass. Unfortunately, our sister planet Venus is an example of a place where greenhouse gases have created an extreme situation. Venus' thick carbon dioxide atmosphere has a surface pressure 90 times that of Earth. It would crush a submarine. Additionally, the thick atmospheric blanket holds in the heat, causing Venus' surface temperature to be 864 degrees Fahrenheit,

2:57hot enough to melt lead. Given that the successful Russian lander's lifetimes on the surface of Venus were measured in minutes, NASA and JPL engineers are exploring the concept of avoiding the use of modern temperature-sensitive electronics by creating a fully mechanical rover. Mechanical computers using levers and gears have an extensive history as eclipse predictors, adding machines, algebraic equation solvers, and more. A modern version of a mechanical computer

3:30would serve as the rover's brain. Power would come from wind turbines allowing the Venus rover to move around on tank-like treads. To communicate its findings, a shutter moving back and forth in front of a radar-reflecting target would allow the rover to blink a signal code to an orbiting radar-pinging satellite in a fashion similar to signal lamps on Navy ships. In the future, the product of such NASA-funded,

4:00out-of-the-box thinking could study the geology of Venus and perhaps even drill a few holes in its surface. For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org program 400 for more information. You are listening to the 365 Days of Astronomy Podcast.

4:31Cool.

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