Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps.  Eps. 115E & 116E: Tied For Third & Buzzed By An AsteroidAlien

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Recently my Catalina Sky Survey teammate Alex Gibbs found his 27th comet. This discovery brings him into a tie for third place, in the list of observers, with my Catalina Sky Survey teammate Rik Hill. 
  • Carson Fuls and Jess Johnson discovered 10’ diameter 2015 DD1.

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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115E: Tied For Third

The appearance of a naked eye comet is one of natures most impressive displays. Humans have regarded these suddenly appearing objects as everything from a sign of an upcoming disaster, to the bringers of water and organic materials to Earth. In 1882 a Sun grazing comet was easily visible in the daytime and was nearly as bright as the edge of the Sun.  

Humans have discovered about 5,000 of the perhaps one trillion potential comets in our solar system. While most of the comets are discovered by large group efforts a significant number continue to be discovered by individuals.

Recently my Catalina Sky Survey teammate Alex Gibbs found his 27th comet. This discovery brings him into a tie for third place, in the list of observers, with my Catalina Sky Survey teammate Rik Hill.  

The rules for naming a comet are complicated and not completely consistent. Basically, if a person is the first to spot a moving object with cometary fuzz it receives their name. Sometimes there are two names attached to a comet especially if the objects discovery was made by a survey and it was first labeled to be an asteroid. In that case the person who discovered telltale cometary gases surrounding it has their name attached.

Not all comets are discovered with large telescopes and sophisticated electronic cameras. They sometimes sneak up on our planet by brightening suddenly. David Levy discovered 8 comets visually with small backyard telescopes. Perhaps, with persistence you too could discover a comet. 

116E: Buzzed By An Asteroid

Recently my Catalina Sky Survey teammates Carson Fuls and Jess Johnson discovered a rapidly moving point of light in the sky. It was subsequently observed by telescopes in Italy, Arizona, New Zealand, and Australia. The Minor Planet Center used these data to calculate this object’s size and orbit. It was given the name 2015 DD1.

Twenty six hours before humans spotted it, this 10 foot diameter space rock came within two and a half Earth diameters of our planets surface and was traveling at 8 miles per second. At that point it was bright enough to be seen in a small telescope had anyone been looking. In the future its orbit allows it to come to about 2,000 miles of the Earth’s surface.

It is likely that 2015 DD1 will eventually enter the Earth’s atmosphere producing an airburst of less than a kiloton to TNT. At night this would generate a spectacular light show and perhaps break a few windows if it happened over a populated area. It is likely that a tiny asteroid of this size enters our atmosphere fairly often. Most of the time such an impact occurs in the daytime or over the ocean and probably goes unnoticed. 

From 2000 to 2013 the Nuclear Test Ban Treaty Organization Network detected 26 explosions in the Earth’s atmosphere which were created by space rocks. The NASA Fireball Network and other US facilities have recorded 556 events in which space rocks of various sizes have impacted our planet. 

Fortunately our atmosphere protects us from space rocks and harmful radiation.

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

End of podcast:

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