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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453 – HAMMER
Moving at about 70,000 mph on it’s path about the Sun, the Earth travels the distance one of it’s diameters, every 7 minutes. Theoretically, If an asteroid on a collision course with our planet could be slowed sufficiently it could be made to pass behind our planet as it orbits the Sun. In a recent scientific paper, NASA funded scientists carefully analyze how a conceptual spacecraft called HAMMER might be used to deflect the 1,600 foot diameter, 86 million ton, asteroid, Bennu, which has a 1 in 2,700 chance of impacting our planet in 2135 and is soon to be visited by the NASA OSIRIS-REx spacecraft on a sample and return mission. These researcher’s mathematical analysis using a number of HAMMER hypothetical spacecraft as either a high speed projectiles or as transportation for nuclear devices exposes how difficult and complex such a set of missions would be. They find that as the time before an asteroid’s impact grows shorter the amount of energy and thus the number of launches required to make it miss us begins to become impossibly large. It appears that at least a 10 year lead time will be required to take effective action stretching our ability to predict orbits far into the future. Thus the best current strategy is to discover and track as many Earth approaching asteroids as possible while at the same time carefully investigating methods including civilian defense measures which could mitigate the effects of a disastrous celestial impact.
454 – Comets and Asteroids
If you set your mind to it, you can find and hold a sample of an asteroid, called a meteorite, which has landed on the Earth’s surface. If you are extraordinarily lucky you could even find and hold one out of a thousand meteorites which is actually a lunar rock ejected from our moon by an asteroid impact long ago. On the other hand, watching major meteor showers like the Eta Aquarii’ds in May, Perseid’s in August, Orionid’s in October, Leonid’s in November, or the Ursid’s in December will allow you to see but not touch comet dust as it enters and burns up in the Earth’s atmosphere. So far the only sample of comet material scientists can study in their laboratories comes from NASA’s Stardust mission which in 2006 which collected dust particles from the coma of Comet Wild 2. This treasure is a sample of primitive solar system material keep in nature’s deep freeze for the past 4.6 billion years. So far it has been used in more than 150 scientific papers. What we have learned has generated a host of new questions relating to how solar systems form, how organic material and water could have come to Earth, and what to look for in distant solar systems which could indicate how they could host liveable worlds. For additional physical samples of cometary materials we may have to wait until if and when a NASA mission to Comet 88P/Howell brings back samples including organic material to Earth in the 2030’s.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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