Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 625 & 626: Record Year & Lunar Impactors

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Asteroid record hunting in 2020 and NASA classifieds some of the Earth approaching objects as Potentially Hazardous Asteroids or PHA’s
  • Teddy Pruyne early discovery of 2020 XK1.

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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625: Record Year

In 2020 the asteroid hunting community discovered 2,946 Earth approaching space rocks orbiting our Sun.  My team, the Catalina Sky Survey, led the pack with 1,542 to our credit.  Our space rock discoveries ranged in size from 3 to 3,400 feet in diameter. Half of them are less than 100 feet in diameter.  Twenty of these celestial visitors have the possibility of coming closer than the communications satellites.  

NASA classifies 42 of the Earth approaching objects we discovered in 2020 as Potentially Hazardous Asteroids or PHA’s for short.  The PHA label means they are large enough and come close enough to Earth to require that we keep special track of them to make sure they don’t change course and become a threat as they encounter other objects in space.  Perhaps the most dangerous PHA we discovered is 2020 LG1, a 1,000 foot diameter asteroid that on its present path can pass between the Earth and Our Moon.  It came to about 26 times the Moon’s distance from us in 2006 will not make another such a close approach to us for the foreseeable future.  

Our team scans the sky every clear night, when the Moon is not too bright,  using 4 telescopes in the Catalina Mountains North of Tucson, Arizona and one telescope on Kitt Peak in the Tohono O’odum Nation to the west. Our mission and passion is to  look for objects which have the possibility of colliding with Earth.  Fortunately we have yet to find an asteroid large enough to do damage that is on a collision course with our home planet.

626: Lunar Impactors

Recently  my Catalina Sky Survey teammate Teddy Pruyne was observing in the constellation of Pisces with our 60 inch telescope on Mt. Lemmon, AZ when he discovered 2020 XK1. Approximately 12 h later this 6 foot diameter space rock passed through the cloud of communication satellites surrounding Earth. Fourteen hours after that 2020 XK1 came near to the moon as it continued on its 2.3 year long orbit about the Sun.  On its current orbit this tiny asteroid travels from near Earth, past Mars, and into the asteroid belt before it comes near to us again.  Teddy’s early discovery means that if 2020 XK1 had been on a collision course with our Moon scientists would have given you a 26 hour advanced notice to go outside and watch as large boulder impacted the Moon.  

Since 2005 NASA has photographed light bursts from hundreds of small meteoroids as they hit the lunar surface.  Most of these impacts produced very faint flashes of light, however, on September 11, 2013 a meteoroid about half the size of Teddy’s discovery impacted the moon traveling at 37,900 mph making an 8 second flash of light as bright as the north star Polaris.   Satellites orbiting the Moon were able to find that this 3 ft diameter flying boulder had made a crater 130 feet wide in the lava filled lunar basin known as Mare Nubium.  Imagine the excitement which will occur when scientists are able invite the people to go outside to witness the impact of a small boulder on the Moon.

For Travelers in the Night this is Dr. Al Grauer

End of podcast:

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