Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 187E & 188E: Space Boomerang & Comet Showers
Organization: Travelers in The Night
Description: Today’s two stroy:
- Rose Matheny discovered WT1190F. This space boomerang spent rocket booster met its fate in a collision with the Earth about 60 miles off of the coast of Sri Lanka, producing a bright, but harmless light show in the noon sky.
- Scientists long have speculated that the orbits of comets in the Oort cloud near the edge of our solar system could be changed by the gravity of nearby stars as the Sun and its planets move past them.
Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona. This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.
He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.
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187E: Space Boomerang
Recently my Catalina Sky Survey teammate Rose Matheny discovered a fast moving point of light in the night sky. Giving it the temporary name WT1190F, Rose posted her observations on the IAU Minor Planet Center’s Near Earth Object Confirmation page. It was then observed by telescopes in Arizona, South Africa, and Japan. Scientists at the Minor Planet Center concluded that WT1190F was not an asteroid and it was temporarily forgotten. Twelve days after Rose discovered it Bill Gray connected Rose’s 2015 observations of WT1190F with two sets of observations by the Catalina Sky Survey telescopes in 2013. It is possible that this object was observed several times in the past and was lost before it could be identified.
Perhaps it was a spent rocket booster about the size of a small automobile. WT1190F’s orbit around the Earth took it from close to us to out past the Moon.This space boomerang met its fate in a collision with the Earth about 60 miles off of the coast of Sri Lanka producing a bright, but harmless light show in the noon sky. My Catalina Survey team captain, Eric Christensen, concluded “This is pretty cool for a lot of reasons, not least of which we won’t have to re-discover the @#%! thing every few years!”
WT1190F provided an opportunity to understand the entry of objects into the Earth’s atmosphere from great distances as well as to prepare for the chance that an asteroid is on a collision course with planet Earth.
188E: Comet Showers
In the Earth’s yearly trip around the Sun, it passes through the trails of old comets and we are treated to meteor showers. The American Meteor Society’s Calendar lists 12, annual, distinct meteor showers along with the parent object which has shed the debris to cause them.
Could there be showers of objects coming into our solar system on a much longer time scale as the Sun and it’s planets orbit the center of the Milky Way at a speed of 139 miles/second?
Well maybe. Scientists long have speculated that the orbits of comets in the Oort cloud near the edge of our solar system could be changed by the gravity of nearby stars as the Sun and its planets move past them. Some of these dislodged comets would likely enter the inner solar system and a few of them could impact the Earth.
Recently Dr. Michael Rampino of New York University and Dr. Ken Caldeira of the Carnegie Institution published a paper in the Monthly Notices of the Royal Astronomical Society, in which they present evidence of a link between impact craters and mass extinctions on Earth. During the past 260 million years these scientists find a cycle of mass extinctions and impacts on our planet which repeats every 26 million years. These two scientists point out that 5 out of the 6 largest impact craters on Earth have extinctions associated with them. The 8 correlations Rampino and Calderia found between the impacts and extinctions are hard to ignore and suggest a cause and effect relationship.
Humans would not likely be on planet Earth thinking about these data if it were not for the asteroid impact which helped to eliminate the dinosaurs 65 million years ago.
For Travelers in the Night this is Dr. Al Grauer
End of podcast:
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