Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 587 & 588: Quiet Sun & Encounter With Saturn

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  •   Images of the quiet Sun during a solar minimum make it look like a relatively static peaceful place.
  • Greg Leonard discovered Comet P/2020 F1 (Leonard) which had very close encounter with Saturn on May 8, 1936.

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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587: Quiet Sun

Images of the quiet Sun during a solar minimum make it look like a relatively static peaceful place.  For years astronomers have known the moonless night sky is darker at solar minimum than it is near solar maximum when the Sun is observed to have spots, flares, and other signs of solar activity.  Recent observations at the Cosmic Campground International Dark Sky Sanctuary, in New Mexico and NASA Satellite observations reveal some interesting new facts.  NASA’s SOHO satellite constantly monitors the solar wind, the stream of mainly protons and electron coming from the Sun.  When the solar wind encounters the Earth’s magnetic field it produces geomagnetic storms, aurora, and other manifestations of space weather.  In the extreme space weather can disrupt our electrical distribution grid and other human activities.  During solar minimum the solar wind blows at an average speed of 240 miles per second with gusts of more than 500 miles/second.

In addition, high speed streams in the solar wind emanate from the holes that develop in the Sun’s corona during solar minimum.  When the Earth enters into such a high speed solar wind stream, the moonless natural night sky can increase in brightness by 50% or more.  At this time at the Cosmic Campground, in New Mexico you can easily see to walk around without a flashlight and with a DSLR camera photograph the sky which to the camera appears to be covered with orange and green cirrus clouds through which you can see the Milky Way.

588: Encounter With Saturn

My Catalina Sky Survey teammate Greg Leonard was asteroid hunting with our 60 inch telescope on Mt. Lemmon, Arizona when he spotted a fuzzy object with a tail moving through the constellation of Virgo.  Greg’s discovery was tracked by telescopes at 15 different observatories around the world.  Comet P/2020 F1 (Leonard), as it is now known, was found to have been previously imaged by asteroid surveys for the past several months without it having been recognized as having cometary activity.  Scientists at the Minor Planet Center used these data to refine Comet Leonard’s orbit revealing it had very close encounter with the planet Saturn on May 8, 1936.  Over all, from 1663 to 2011, seven comets had close encounters with Jupiter and two had close encounters with Saturn.  

The most spectacular of these interactions occurred in the 1990s when Comet Shoemaker-Levy 9 was found orbiting Jupiter and was ripped to pieces by the giant planet’s gravity.  Comet Shoemaker-Levy 9’s fragments entered Jupiter’s southern atmosphere producing atmospheric disturbances which could be seen for months in small telescopes from Earth.   More frequently Jupiter snags smaller comets like Comet C/2020 F1 Leonard producing a family of small comets circling the Sun with orbital periods of 20 years or less.  After the Sun evaporates  water ice and other frozen substances, such an object  becomes indistinguishable from countless other small asteroids. 

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

End of podcast:

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