Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 239E & 240E – Fresh Lunar Crater & The King

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s two stroy:

  • Some lunar craters are new. The moon is being hit by objects in the present epoch. Fresh lunar craters tell us about objects which enter the Earth-Moon system.
  • Jupiter protects us as well as directs some objects our way. Jupiter, the king of our solar system, has provided us with a place to stand and air to breathe.

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:  Big thanks to our Patreon supporters this month:  Paul M. Sutter, Chris Nealen, Frank Frankovic, Frank Tippin, Jako Danar, Michael Freedman, Nik Whitehead, Rani Bush, Ron Diehl, Steven Emert, Brett Duane, Don Swartwout, Vladimir Bogdanov, Steven Kluth, Steve Nerlich, Phyllis Foster, Michael W, James K Wood, Katrina Ince, Cherry Wood.

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

Or please visit our Patreon page:


239E – Fresh Lunar Craters
Without an atmosphere and running water, craters formed on the Moon remain visible for eons. They are interesting targets for Earth bound observers with small telescopes to explore and photograph.

Not all of the Moon’s craters are old. Amateur and professional observatories routinely monitor the moon to detect some of the bright flashes which occur. Since 2006 the NASA Lunar Monitoring program has recorded more than 300 flashes created by meteor impacts on our Moon. The brightest so far was on March 17, 2013. Dr. Mark Robinson of Arizona State University headed up a team which analyzed recent data from the NASA Lunar Reconnaissance Orbiter. This team of researchers were able to spot the 62 foot diameter crater which was created by the impact that produced the March 2013 flash. They were also able to identify more than 200 lunar surface changes, out to almost 19 miles from the impact crater, which were caused by this event. This group of scientists were also able to verify that the impact of micrometeorites has modified the lunar soil to a depth of several feet or more.

Fresh craters on the Moon tell us about the number and the size distribution of objects which enter the Earth-Moon system. Current estimates suggest there are 24 craters larger than 60 feet in diameter which are produced on our Moon each year. Structures for lunar colonists and lunar experiments need to protect them from these as well the many many more BB sized or smaller objects which arrive at gun shot speeds from all directions in space.

240E – The King
The planet Jupiter is so bright that you can even spot it under the artificial light dome of one of our cities. Jupiter has a mass of more than 300 times that of the Earth and contains more than twice the mass of all of the other planets, dwarf planets, asteroids, and comets in our solar system combined.

Jupiter has had an enormous influence on the evolution of our solar system. It appears to have cleared out the inner solar system leaving enough rocky debris to form Mercury, Venus, Earth, and Mars. Without this action our solar system is likely to have turned out like the more than half of the planetary systems which we have found. These distant solar systems consist of non-inhabitable super Earth sized planets orbiting closely about their host stars.

In terms of the defense of planet Earth from impacting objects, Jupiter is a mixed blessing. It apparently deflects some of the long period comets out of Earth impacting orbits while sending some asteroids and comets our way. In 1770 a small comet came in from the outer solar system and passed near Jupiter. This encounter sent it straight towards Earth. Fortunately the King’s aim wasn’t perfect and this celestial visitor missed humanity by about a million miles. After two orbits of the Sun this comet once again passed near Jupiter. This time the King ejected it into interstellar space.

Look up where to find Jupiter on the internet and observe it. Jupiter is an awesome sight in binoculars or a small telescope. As you view this gas giant contemplate the fact that it is likely the reason you have a place to stand and air to breathe.

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

365 Days of Astronomy

The 365 Days of Astronomy Podcast is produced by Planetary Science Institute. Audio post-production by Richard Drumm. Bandwidth donated by and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. 

This show is made possible thanks to the generous donations of people like you! Please consider supporting to our show on and get access to bonus content. 

After 10 years, the 365 Days of Astronomy podcast is entering its second decade of sharing important milestone in space exploration and astronomy discoveries. Join us and share your story. Until tomorrow! Goodbye!