Dec 9th: Going Far & Small But Deadly

By on December 9, 2018 in

Podcaster: Dr. Al Grauer
Travelers in the Night Digest: Eps.451 & 452: Going Far & Small But Deadly

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Jess Johnson discovered Comet C/2018 F3 (Johnson)! It’ll be back in 2037.
  • Greg Leonard discovered 2018 FO5, a three football field diameter asteroid that can come closer than our Moon.

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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451 – Going Far
My Catalina Sky Survey teammate Jess Johnson was very surprised when the large comet with a long stringy tail, which he has just imaged with our 60 inch telescope on Mt. Lemmon, Arizona, was an unknown object. Jess quickly emailed his discovery observations along with a description of the comet’s coma and tail to the Minor Planet Center. Over the next eight days astronomers at 11 different observatories around the world tracked Jess’s new comet. Scientists at the Minor Planet used these data to calculate it’s path around the Sun, verify it to be a comet, and give it the name C/2018 F3 (Johnson). We now know that Comet C/2018 F3 (Johnson) had crossed the orbit of Pluto in 1997 and had reached it’s closest point to the Sun 217 days previous to Jess’s discovery observations. Further, about two weeks before Jess spotted it , moving through the constellation of Leo, Comet 2018 F3 (Johnson) had streaked unnoticed past the Earth. Unfortunately Jess’s comet is likely to be visible only in electronic camera images and in 2037 will once again cross Pluto’s average distance from the Sun on a path which will take it into truly deep space. Until a few years ago all of the comets human astronomers had observed originated in the distant regions of our solar system, the Kuiper Belt or the Oort Cloud . Perhaps C/2018 F3 (Johnson) is an interstellar visiting Comet and is thus a sample of a place currently beyond our reach.

452 – Small But Deadly
My Catalina Sky Survey teammate Greg Leonard’s discovery of, 2018 FO5, a three football field diameter asteroid that can come closer than our Moon is a reminder that we need to keep searching for the many thousands of Potentially Hazardous asteroids larger than 500 feet in diameter which are likely to exist. An asteroid the size of Greg’s discovery, 2018 FO5, strikes the Earth every 50,000 years or so creating a crater 2 miles in diameter and 2,000 feet deep. Structures 10 miles from such an impact would experience a 283 mph wind causing multistory and wood framed buildings to collapse. The ground would shake as in a magnitude 6 earthquake and 90 percent of the trees in the area are likely to be blown down by the air blast. This extremely remote possibility is the reason for NASA’s goal to find the 15,000 or so such city threatening asteroids which are suspected to exist. At our current rate of discovery it will take asteroid hunters decades to achieve this goal. Currently there are only a few hundred people world wide looking for such dangerous asteroids. My 11 member team, the Catalina Sky Survey discovered 43 of 118 dangerous asteroids which were found in 2017. To move at a faster pace we will need more telescopes and more asteroid hunters to operate them.

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

End of podcast:

365 Days of Astronomy
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