Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: 335& 336: DART & Meteorite Mystery
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- DART is a projected asteroid deflection test mission. 65803 Didymos has a moon that will be the target of the test.
- Dr. Geoffrey Evatt of the University of Manchester is studying the transport of meteorites on and through Antarctic ice flows.
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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Transcript:
335 – DART
A stony asteroid 130m or about 430 feet in diameter has a mass of 3 billion Kg or 6.5 billion pounds. Such an object is likely to strike the Earth every 11,000 years or so creating a crater a mile in diameter crater and inflicting damage over a hurricane sized footprint on the surface of our planet. If one like this were found to be heading straight for us deflecting it would take some ingenuity. The key is early discovery so that perhaps a gentle nudge would do the trick. How do do we test such an idea before we are in a situation where the test occurs on an incoming impactor where failure is not a good option?
In a clever approach to this problem scientists at NASA, the European Space Agency, and several universities have been funded to develop DART, a projectile spacecraft, which is being designed to strike the small moon located in the binary near Earth asteroid (65803) Didymos. The impact of NASA’s DART 1,100 lb space craft traveling a 6KM/s or about 13,000 mph has been calculated to produce a 1% change in the asteroid moon’s orbit. The impact’s effect is planned to be measured by Arecibo and Goldstone RADAR telescopes.
The DART impactor experiment will enable researchers to calibrate the potential of a collision to shift the path of an asteroid whose size poses a real threat to the citizens of planet Earth.
336 – Meteorite Mystery
A research expedition to near the south pole is developing to investigate a meteorite mystery. Meteorites landing on the Antarctica ice sheet are slowly transported along by ice flows until they are dumped into the ocean or up against a mountain range. The concentration of meteorites into stranding zones on the lower slopes of mountain ranges has allowed humans to collect 2/3 of the meteorites discovered on Earth in Antartica. The fact that the percentage of iron meteorites found in these places in Antartica is 1/8 what are found elsewhere on Earth is puzzling.
To investigate this problem Dr. Geoffrey Evatt led a team from the University of Manchester in the UK which has conducted experiments and published the results in Nature Communications. Their work shows that real meteorites with a high thermal conductivity, such as irons, when exposed to solar warming, can sink faster than the upward movement of the ice and thus be trapped below the surface and be missed by human meteorite collectors. With only 2 or 3 meteorites per square mile they will need a sensitive search technique that doesn’t miss anything. After testing their special mine sweeping equipment in Norway these scientists will survey possible Antarctic sites, and finally be able to search in earnest near the Trans Antarctic Mountains in 2019 and 2020. What they find is likely to open a new chapter in solar system exploration right here on planet Earth.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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