Podcaster: Dr. Al Grauer
Title: Travelers in the Night Eps. 627 & 628: Toughest Asteroids & Close Approaches
Organization: Travelers in The Night
Description: Today’s 2 topics:
- 14 extremely tough asteroids which regularly travel closer to the Sun than the planet Mercury
- Hannes Groeller discovered 2020 JJ.
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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627: Toughest Asteroids
In 2020 my team the Catalina Sky Survey discovered 14 extremely tough asteroids which regularly travel closer to the Sun than the planet Mercury. On each close solar approach the surface of these death defying space rocks has been heated to a temperature which would easily melt lead. These hardy space rocks move about the Sun with orbital periods of less than 4 years which means they have had a scorching solar encounter many times in the past. Perhaps the toughest of this years lot is 2020 DD. At its closest point to the Sun it receives 7 times more solar energy than heats the surface of Mercury to 800F. 2020 DD
is about 225 feet in diameter and orbits the Sun on a path which takes it from a point approximately 1/3 Mercury’s distance from the Sun out to way past Mars and back again once every 4 years. On occasion 2020 DD and three more of our 2020 extremely tough space rock discoveries can come to less than two times the Moon’s distance from us.
This group of Earth approaching asteroids is able to withstand extreme temperatures without turning into dust clouds. Thus it is likely they contain at least as much iron, nickel, platinum, gold, and other valuable metals as a stony meteorite and may be worth billions of dollars on the used metal markets. The bottom line is that in addition to being a curiosity very tough space rocks could very well become an important source of raw materials for future asteroid mining space colonists.
628: Close Approaches
In 2020 my team the Catalina Sky Survey discovered 171 asteroids which can occasionally come closer to us than our Moon. In fact 21 of them, averaging 25 feet in diameter can come close enough to our home planet to pass through the cloud of communications satellites which surround Earth. The closest approaching of all of them is 2020 JJ. It was discovered by my Catalina Sky Survey teammate Hannes Groeller while asteroid hunting in the constellation of Cannes Venatici with our 60 inch telescope on Mt. Lemmon, Arizona. 6h and 12 minutes after Hannes discovered it, 2020 JJ, a 10 foot diameter space rock, passed 4300 miles above the surface of the Pacific Ocean. During its death defying encounter, Earth’s gravity deflected 2020 JJ’s trajectory by some 30 degrees sending it on a new orbit about the Sun.
According to the Purdue University and Imperial College of London’s impact calculator a space rock the size of 2020 JJ enters the Earth’s atmosphere 2 or 3 times a year, creates a spectacular fire ball meteor, and rains fragments traveling at 5.5 mi/second onto the Earth’s surface. If you are fortunate enough to witness such an event report your fireball observations to the American Meteor Society. On the American Meteor Society’s Fireball logs website you can learn where and when fireballs were witnessed around the world and perhaps even some locations for you to look for meteorites on the Earth’s surface.
For Travelers in the Night this is Dr. Al Grauer
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