Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 617 & 618: One To Track & Tremendous Find

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Teddy Pruyne discovered 550’ diameter 2020 TF in the constellation Lacerta.
  • David Rankin discovered 1 Km+ diameter 2020 UP3 when it was coming towards us from the direction of the Sun!

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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617: One To Track

Recently my Catalina Sky Survey teammate Teddy Pruyne was observing in the constellation Lacerta with our 60 inch telescope on Mt. Lemmon, Arizona when he spotted an unknown point of light streaking through the night sky.  For the next 5 nights astronomers in Arizona, Spain, Tican, Illinois, Pennsylvania, and England tracked Teddy’s discovery and reported their observations to the Minor Planet Center.  Scientists used these data to calculate a 414 day long tentative path about the Sun, estimate it’s size to be 550 feet in diameter, and give it the name 2020 TF. With only 5 days of data its path remains uncertain.  In fact on November 2, 2064 this potentially dangerous asteroid is predicted to come between 1 and 17 times the Moon’s distance from us.  Typically as asteroid hunters continue to track an object the chances it will strike the Earth decrease to essentially zero.

According to the Purdue University and Imperial College of London’s impact calculator, approximately once every 25,000 years or so, an asteroid the size of 2020 TF enters the Earth’s atmosphere, breaks up at an altitude of 188,000 feet,  hits the ground in a broken state at 9 mi/s, and creates a crater 1.9 miles in diameter and 2,100 feet deep in sedimentary rock.   If you were 50 miles from the point of impact it would feel like a 6.1 Richter Scale magnitude earthquake and hear a loud noise like a truck striking a building about 4 minutes later.

618: Tremendous Find

Depending on the angle between the Sun, an asteroid, and Earth we see an asteroid in various phases like the Moon. An asteroid appears “full” or completely illuminated if it approaches us from a direction opposite to the Sun and as “new” or completely dark when it comes towards us from the direction of the Sun. Recently my Catalina Sky Survey teammate David Rankin searched for asteroids, as close to the Sun as possible with our 60 inch telescope on Mt. Lemmon, Arizona. His efforts were rewarded when he discovered 2020 UP3, illuminated like a thin crescent moon, trying to sneak by asteroid hunters in the evening twilight. This was a tremendous find since 2020 UP3 is more than 1 Km in diameter and is thus large enough to create significant damage if it entered our atmosphere.

According to the Purdue University and Imperial College of London’s impact calculator an asteroid of this size enters the Earth’s atmosphere once every 240,000 years and creates a crater 5.6 miles in diameter and 1,900 feet deep in sedimentary rock. 100 miles from such an impact the ground would shake as in a 7.3 Richter scale magnitude earthquake, there would be hurricane force winds, and the ground would be covered with 1/2 diameter asteroid produced gravel. Currently 2020 UP3 travels on a very elliptical path about the Sun which is inclined by 49 degrees to the plane of the solar system. Fortunately on its current path there is zero chance that 2020 UP3 will impact Earth, however, asteroid hunters will continue to track it to be sure it doesn’t become a threat at it passes near Venus, Earth, Mars, and Jupiter. 

End of podcast:

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