Dec 17th: Big and Fast & Asteroid Defense


Podcaster: Dr. Al Grauer
Travelers in the Night Digest: Eps. 349 & 350: Big and Fast & Asteroid Defense

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Dr. Grauer discovered 2017 FE101 which can’t come closer than 21LDs (Lunar Distances). It bears watching, though, so that a close pass by Earth or Mars doesn’t change its orbit and make it a danger to Earth.
  • The Chelyabinsk impact in 2013 puts us all on notice that we need a defense. The Catalina Sky Survey is a key part of this defense.

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.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2017, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at

349 -Big and Fast
If you are luckier than a hundred million dollar power ball winner you will see your space rock as a meteor streaking across the sky, fall to the ground, and land in a place where can you walk over and pick it up. On the other hand, with more persistence than luck you can find a space rock where it has been waiting for you on the surface of planet Earth. First you need a place to look. Dry lake beds have few surface rocks and can be a great place to find meteorites. There are strewn fields from known celestial falls that you can check out. On private land will you need the owner’s permission. If you live near BLM land you can collect up to 10 lbs of meteorites a year without a special permit. Train your eye by looking at photos of meteorites and/or make a visit to a museum to view the real thing. A dark fusion crust is a clue. Thumbprint like surface features is another. A powerful magnet will tell you if your candidate has a high iron content consistent with meteorites An exciting new way to find freshly fallen space rocks involves the use of Doppler weather RADAR to track pieces of an exploding fireball on their way to Earth. There are web sites which can alert you to places to travel and search.

You will probably need to consult an expert to determine if your space rock is from the asteroid belt, the Moon, or Mars. Holding an object older than any other rock on the ground which is billions of years old and has traveled an unimaginable distance to be with you will be your payoff.

350 -Asteroid Defense
A clear night with excellent pinpoint star images allowed me to discover 16 near Earth approaching asteroid candidates with the Catalina Sky Survey 60 inch telescope on Mt Lemmon, Arizona. This 9 hr period of time provides us with a snap shot of the kinds of objects which constantly zip past our home planet. Thirteen of the candidates turned out to fit the definition of an Earth approaching object, two were lost because of a lack of additional observations, and the other one is an inner main belt asteroid which for a time imitated an Earth approaching object The thirteen close approachers travel about the Sun with orbital periods ranging from 3.6 years to only 248 days. The largest is more than a quarter of a mile in diameter while the smallest is about the size of a small U-Haul truck. Most of them stay relatively far from Earth with the closest approacher having the possibility of coming to within three quarters of the Moon’s distance from our home planet. One of the more interesting members of the group is 2017 FU90, a 100 foot diameter space rock which makes frequent visits to the vicinities of Mercury, Venus, Our Moon and Earth. It must be made out of pretty tough stuff since it doesn’t melt or evaporate when once every 248 days it is closer to the Sun than the planet Mercury. If it is composed largely of iron, nickel, and other metals it could be a target for space mining. Astronomers will need to obtain a spectrum of the patterns of colors of sunlight it reflects to get an idea of its chemical composition.

For Travelers in the Night this is Dr. Al Grauer.

End of podcast:

365 Days of Astronomy
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