Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 615 & 616: Solar Storm Forecasts & 100 Million Year Old Crater

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

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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615: Solar Storm Forecasts

The Earth’s atmosphere and magnetic field protect us from dangerous space weather events such as coronal mass ejections from the Sun. 

Most of these solar outbursts are relatively mild.  Some of the largest are sausage shaped solar burps of billions of tons of protons and electrons which come into our neighborhood at from 12 to 2,000 miles per second.  One of them could  put astronauts, airline passengers, power grids,  electronic devices, and satellites at risk.  

The Sun produces a coronal mass ejection every 5 days or so during solar minimum and perhaps as many as 3 or 4  per day when the Sun is at its most active state. They take anywhere from 13 hours to 88 days to reach the Earth’s orbit.  Being able to forecast the strength and time of arrival of a coronal mass ejection  can help humans and their equipment assume a defensive posture if necessary.  Recently a team of researchers led by Dr. Luke Barnard of the University of Reading published a paper in the journal AGU Advances.  

This paper reports that forecasts of the arrival time of a coronal mass ejection is improved by 20% using analysis performed by thousands of members of the public.   Participants in the Solar Stormwatch citizen science project estimate the size and shape of coronal mass ejections using pictures taken by the NASA STEREO Spacecraft.  So far in addition to having the thrill of discovery these citizen scientists have contributed to 7 scientific papers.  To learn how to do this exciting research and become a member of a world wide community of solar storm watchers go to the Solar Stormwatch II website.

616: 100 Million Year Old Crater

In western Australia, rock samples and maps of the local geology obtained while exploring for gold show evidence of a 3 mile diameter meteor crater which features a small central pucker like protrusion.  Before erosion filled it in, the Ora Banda crater must have looked something like the craters on the Moon which have a central mountain peak.  You can’t see the Ora Banda crater as you hike the outback because erosion has filled in the original structure leaving only a shallow depression in the flat desert floor

.  Even so, the rocks beneath your feet could only have been created by a nuclear blast or a meteor impact. Dr. Jayson Meyers lead geophysicist for the Perth based gold prospecting group which discovered it suspects the Ora Banda crater was produced when a relatively large space rock hit the Earth some 40 to 250 million years ago. If and when samples of the original space rock are found its size and speed may be more accurately estimated.  For example according to the Purdue University and Imperial College of London’s Impact calculator, a 2.5 football field diameter, dense rocky space rock, enters the Earth’s atmosphere at 20 mi/s once every 63,000 years or so producing a 2.8 mile diameter crater in sedimentary rock. 

25 miles from impact you would experience the effects of a 6.6 Richter scale magnitude earthquake and be knocked to the ground by a 182 mph wind. Fortunately, asteroid hunters have yet to find a space rock like this with our number on it. 

End of podcast:

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