Organization: Travelers in The Night
Description: Today’s 2 topics:
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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441 – Carson’s Pair
My Catalina Sky Survey teammate Carson Fuls was observing, in the constellation Lynx, with our Schmidt telescope on Mt. Bigelow, Arizona , when within the space of only 35 minutes, he discovered two small space rocks well before they made very close approaches to Earth. 79 hours after Carson discovered the first, 2018 CB, this approximately 70 foot diameter space rock passed about 1/5 of the Moon’s distance from us. Turns out that the second of Carson’s duo, an approximately 50 foot diameter space rock got near us first, when 62 hours after Carson discovered 2018 CC, it came to less than 1/2 of the Moon’s distance from the surface of planet Earth. Since we didn’t have a large enough, properly equipped telescope to measure the pattern of colors each of Carson’s discoveries reflects from the Sun we can only estimate their physical sizes and guess at their densities and chemical compositions. In any event, if either of these space rocks were to strike the Earth they would likely explode at an altitude about 100,000 feet above the Earth’s surface, releasing the energy of tens of thousands of pounds of TNT, producing a spectacular light show. Both of Carson’s discoveries could be similar to the space rock which exploded over Chelyabinsk, Russia breaking windows, injuring nearly 1,500 people, and producing numerous fragments which made it to the ground. If either of Carson’s discoveries had been on an impact trajectory with Earth, asteroid hunters would have had time to warn people in the effected area to stay away from doors and windows.
442 – Brian’s Debut
During the only 3 clears hours of his first night solo as an asteroid hunter, my new Catalina Sky Survey teammate Brian Africano discovered two new Earth approaching asteroids with our Schmidt Telescope on Mt. Bigelow, Arizona. Brian came to us with a rich family and work history in astronomy and has quickly learned the additional skills required to make space rock discoveries. Brian’s first discovery of the night, 2018 DR is small. In only about 20 hours of observations asteroid hunters determined that it is no threat to us. Brian’s second discovery of the night 2018 DG1 is a different story. Since it is almost 300 feet in diameter, astronomers at 18 different observatories around the world stayed on it for more than 68 hours, after Brian posted his discovery observations, to determine a reasonable orbit for it. According to the Purdue University and Imperial College of London’s impact calculator, an asteroid the size of 2018 DG1 strikes the Earth every 2,300 years or so releasing the energy of 19 million tons of TNT. Such an impactor would likely burst into fragments at an altitude of 14,000 feet and not make a crater even though some large pieces of it could make it to the ground for meteorite enthusiasts to find. Fortunately, Brian’s discovery, 2018 DG1, will not impact the Earth in the foreseeable future and will not come very close to us again until September of 2170, when it will pass about one and a quarter million miles from humanity.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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