Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Eps.443 & 444: Unsung Heroes & Near Comets
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- When asteroid hunters find a moving point of light in the night sky they have no idea of what the object is or where it might be located without additional observations.
- Greg Leonard discovered comet C/2017 Y3 (Leonard) which orbits the Sun once every 31 years on a path which can bring it to about 191 times the Moon’s distance from us.
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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Transcript:
443 – Unsung Heroes
When asteroid hunters find a moving point of light in the night sky they have no idea of what the object is or where it might be located without additional observations. The situation is similar to the fact that you can’t tell if a basketball will go through the hoop when it has only traveled a foot from the shooter’s hand, you need to see more of it’s path. Often in the media, the observer or group which first discovers an object is prominently mentioned, however, in almost every case we wouldn’t have a clue about what the object might be without accurate follow up observations by unmentioned observers around the world. For example, in 2017 observers in 50 countries at 440 different observatories made nearly 19 million observations of asteroids and comets which enable scientists to calculate where about 800,000 objects will be in the future. Additionally, scientists at the Minor Planet Center have the sometimes thankless job of keeping track of all of these data. Finally without the group of scientists at JPL’s Center for Near Earth Object Studies and independent scientists like Francesco Manca at the Sormano Observatory in Italy who use observations to calculate when objects make close approaches to our Earth and Moon we would have no idea about what is going on in our neighborhood. NASA’s Planetary Defense Coordination Office funds most of the discovery activities and is the main reason we know about objects which are coming near to Earth.
444 – Near Comets
Recently my Catalina Sky Survey teammate Greg Leonard discovered one of the only, one hundred of the nearly 18,000 Earth approaching objects which are known to be comets. Comet, C/2017 Y3 (Leonard), orbits the Sun once every 31 years on a path which can bring it to about 191 times the Moon’s distance from us. It is unlikely to come any closer unless it passes near to Jupiter or Saturn in the far distant future. Although no comet nucleus impact on the Earth has been conclusively identified, there is some evidence that suggests the 1908 Tunguska event in Russia, which knocked down trees over a 770 square mile area, could have been caused by a fragment of Comet Encke. However there is no doubt that the Earth’s collision with dust and small debris left trailing from comets produces some of the meteor showers we enjoy so much. Comet Temple-Tuttle came closer than 9 times the Moon’s distance from Earth in 1366 and has left behind a trail of debris which we know as the November Leonid meteor shower. In 1966 it produced meteor storm during which people saw as many as 40 meteors a second. Comet 109P/Swift-Tuttle orbits the Sun once every one hundred and thirty years leaving a trail of debris causing the Perseid meteor shower. Look for the Perseids to peak in the early morning hours of August 12-13, 2018.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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