Organization: Travelers in The Night
Description: Today’s 2 topics:
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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483 – Double Trouble
Approximately 15 % of the known Earth approaching asteroids are binaries. Most of these consist of a large object circled by a much smaller satellite. When asteroid hunters on my team, the Catalina Sky Survey, and the Morocco Oukaimeden (Oukaï-meden) Sky Survey discovered what is now called 2017 YE5 it appeared to be an unknown moving point of light in their images. Astronomers were thus surprised when they directed RADAR pulses from the Arecibo Observatory in Puerto Rico towards 2017 YE5 and then analyzed the reflected signal which was received by Green Bank Observatory (GBO) in West Virginia. The RADAR images they obtained clearly show 2017 YE5 to be two, nearly equal sized, asteroids orbiting a common center of gravity once every 20 to 24 hours. In visible light these two asteroids are likely to appear as dark as charcoal bricks making them much larger than the sunlight they reflect would suggest. Interestingly , although nearly equal in size, the two components of 2017 YE5 have different RADAR brightnesses. These data suggest that the two objects now it a close dance with each other have different densities, compositions near their surfaces, different surface terrain, and perhaps a totally different place of origin within the solar system. How they came to be together and what humans would do if such a large double trouble object is heading for us remains a mystery.
484 – Aliens
Most Astronomers find it hard to believe that given perhaps a trillion planets in the Milky Way alone that our Earth is the only one which hosts living organisms.
Thoughtful estimates suggest that there maybe somewhere between 10 and 10,000 technical societies inhabiting some of the millions of Earth like planets in our home galaxy. Using our rocket technology any one of them could colonize our galaxy in 5 to 50 million years. Since such waves of colonization should have happened several times in the past, one is left with the question: “Where are they”? Despite a considerable expenditure of time and money scientists have been unable to find any proof these technological societies exist never mind that they have ventured forth from their home planets. Many, if not, a majority of people believe that UFOs are piloted alien spacecraft and that the governments of the world have conspired to keep this information from them. In reality, casting aside obvious hoaxes, about 5% of UFO sightings cannot be easily explained by human activity or weather phenomena. At this point the leap that these sightings are alien spacecraft seems unjustified. However some serious scientists continue to call for a careful investigation of each such event. It is both exciting and terrifying to realize we have no concept of what living forms may exist outside Earth in the Milky Way.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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