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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495 – Catching Asteroid
The long time goal of asteroid hunters is to find potentially dangerous asteroids far from Earth where a tiny push would make it miss our home planet. Turning that around, Minghu Tan, a PhD student at the University of Glasgow has been investigating the possibility of deflecting a small asteroid causing it to graze the Earth’s atmosphere and thus use aerobraking to put the small space rock into Earth orbit. Tan, the lead author of a paper published in Acts Astronautica outlines a procedure in which a small asteroid rich in precious metals, water, or other materials useful to space colonists is captured using the drag of the Earth’s atmosphere to slow it down and place it into an accessible orbit. Tan and his fellow researchers would minimize the risk to Earth by selecting one of the thousand or so candidates less than 100 feet in diameter, which if things went wrong and it entered the Earth’s atmosphere, would burn up before it hit the ground. Critics point out that the target of such a maneuver would have to be carefully selected to make sure that it’s composition and physical make up do not turn the asteroid mining experiment into a nasty surprise. Far fetched as Tan’s proposal sounds there is no getting around the facts that obtaining valuable materials from asteroids could be cost effective and that currently the NASA OSIRIS-REx mission is sampling the asteroid Bennu. Who can say which of the current science fiction proposals will eventually become a human accomplishment.
496 – Boomer
The fireball meteor streaking across the sky the early evening of January 17, 2018, witnessed by 700 observers in 11 States and Canada was also recorded by infrasonic microphones and seismometers. Recently Dr. Michael Hedlin of Scripps Institution of Oceanography and a team of scientists published a paper in Seismological Research Letters which reports on their analysis of atmospheric sound and earthquake wave data from this event. These researchers used these data to determine the location, altitude, and energy released during this celestial visitors violent death. By comparing their results with images from ground based cameras and data obtained by a lightning mapper on a National Oceanic and Atmospheric Administration satellite these scientists were able to determine that the energy released by this fireball meteor’s explosion was equivalent to 2.2 tons of TNT. They estimate their analysis methods could each year detect 15 such bolide events over Eastern North America using the existing network of microphones and seismometers. The payoff from this effort will be the ability to assess the risks presented by the 2,000 large fireball meteor explosions which occur each year world wide and will allow scientists to detect any secret nuclear tests being conducted by rouge individuals or governments.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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