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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481 – Fireball
On July 8, 2018 a beautiful fireball Meteor was seen streaking across the sky in evening twilight. So far the American Meteor Society has received more than 700 reports of this event , from observers in Iowa, Illinois, Minnesota, Indiana, Kansas, Nebraska, Ohio, Michigan and Wisconsin. These eye witnesses describe the fireball as having had a white center surrounded by an intense greenish blue cloud. Some lucky viewers were treated to a 10 second view of this event. By combining all of the eye witness reports scientists were able to construct a 3D path which appeared to indicate that the parent object had a atmosphere grazing trajectory. Since 255 observers reported seeing the fireball fragment into pieces it is possible, that instead, the parent meteoroid came in at a steep angle and broke into pieces high above the Earth’s surface. Currently no meteorites from this event have been found. In the first 6 months of 2018 the American Meteor Society has received 274 fireball sightings with at least 5 reports each. If you witness a fireball meteor and/or record a fireball with your dash cam or security camera report it to the American Meteor Society and become citizen scientist. Your data will be very important in finding out where it came from in the solar system as well as to indicate where it might be possible to find pieces of it on the ground.
482 – Botwana Fragment
My Catalina Sky Survey teammate Richard Kowalski discovered 2018 LA moving through the constellation of Scorpio. Next security cameras spotted what had been the 6 foot diameter space rock, 2018 LA, as it turned into a fireball meteor and exploded high above Africa. The latest is that a team of scientists from Botswana, South Africa, Finland, and the United States have recovered a piece of this former asteroid in Botswana’s Central Kalahari Game Preserve. Their discovery of a tiny freshly fallen meteorite came after 5 days of walking and searching. Their task was made difficult by the winds which had scatted 2018 LA’s fragments as they descended through our atmosphere. These researcher’s find is a priceless uncontaminated sample of material from the primitive solar system. Further, knowing the chemical composition of what had been 2018 LA will help to defend planet Earth. Here’s how. In asteroid hunter’s telescope an Earth approaching object is a moving point of light. To estimate its size we need to know the percentage of sunlight a space rock reflects toward us since a very large dark object will have the same brightness as a small ice covered one when both are at equal distances from Earth. Chemical analysis of what had been 2018 LA will give us its reflectivity and thus an accurate estimate of its size. This calibration will help humans to prepare for and defend against a much larger object with our number on it.
For Travelers in the Night this is Dr. Al Grauer.
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365 Days of Astronomy
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