Travelers in the Night Eps. 281E & 282E: Close Passes & Tilted History

The 365 Days of Astronomy

Dr. Al Grauer hosts. Dr. Albert D. Grauer ( @Nmcanopus ) is an observational asteroid hunting astronomer. Dr. Grauer retired from the University of Arkansas at Little Rock in 2006. travelersinthenight.org

Today's 2 topics:

- During a recent 3 night observing run my Catalina Sky Survey teammate Rose Matheny discovered 4 asteroids which can come to less than one half the Moon's distance from us. Interestingly one of them passed about 25,000 miles over the South Pole 2 days after Rose discovered it. Rose's four close approaching asteroids are small ranging in size from 15 to 60 feet in diameter. None of them are big enough to reach the Earth's surface and make a crater. However, the largest is about the size of the one whose air blast shock wave injured nearly 1500 people when it exploded over Chelyabinsk, Russia in 2013 .

- Seasons are created by the fact that the Earth's axis of rotation is currently tilted 23 1/2 degrees relative to our path around the Sun. The slight out of roundness of the Earth's orbit combined with a 41,000 year cycle in its 3 degree axis of rotation wobble can cause the Earth's climate to change on very long time scales. Turns out that these astronomical cycles are likely to be the drivers of where you are from and where you live.

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