Jul

16

2017

Prof. David Paige

Ice deposits at the poles of the Moon and Mercury

Location: Geology 3656
Time: 2:30PM

Surficial ice evaporates relatively quickly if exposed to sunlight in the inner solar system. However, some parts of craters near the poles of Mercury and the Earth’s Moon are in permanent shadow. If a water molecule lands in such a spot it is expected to stay there until it evaporates due to heat from a micrometeorite or a photon from a star other than the Sun. New spacecraft data support the interpretation that there is ice in these shadowed regions. Picture: Lunar mosaic of the south pole (GSFC/NASA/Arizona State University)

Jun

25

2017

Dr. Frank Kyte

Eltanin, the largest meteorite of which intact fragments are preserved

Location: Geology 3656
Time: 2:30PM

The largest recovered meteorite was discovered at the bottom of the Pacific Ocean about 1500 km west of the southern tip of South America. It has been documented by sediment cores collected during a series of German oceanographic cruises. About 2.5 million years ago a one-kilometer-diameter asteroid impacted the ocean and deposited more than one kilogram of meteorites per square meter over thousands of square kilometers. About 90% of this was melted by the shock of the impact, but 10% is undamaged meteorite fragments.

May

14

2017

Prof. Kevin McKeegan

The Great American Eclipse of 2017

Location: Geology 3656
Time: 2:30PM

On Monday, August 21, 2017, a total eclipse of the Sun will be visible in the continental United States for the first time in almost 40 years. During a total eclipse the Sun is completely hidden by the Moon, the sky becomes dark, and the faint atmosphere (corona) becomes visible - looking like a beautiful halo. The eclipse will be total along a track stretching from Oregon to South Carolina. In Los Angeles the eclipse will be only partial with 2/3 of the Sun being eclipsed. Kevin will discuss a few historically important eclipses, some general eclipse phenomena, and where and how to view the total eclipse. Photo credit: NASA

May

9

2017

Prof. John Wasson

It Fell From The Sky!

Location: Fowler Auditorium
Time: 6PM

On April 3, 1916, the 139-pound Treysa iron meteorite fell in Germany. Witnesses reported hearing a thunder-like detonation and seeing a cloud of smoke as a result of the fall. Alfred Wegener, a pioneering geophysicist who hypothesized continental drift, used eyewitness reports to calculate where the meteorite came down. After a suspenseful year-long search, the meteorite was extracted about half a mile from the predicted location. Meteorite falls are spectacular and captivating. Fragments that can be found in our backyards connect us all to far-off worlds and the origins of the solar system. Come and hear more about their impact throughout history and today. The event is free and open to the public. Reserve your seat today at meteorites.eventbrite.com!

Apr

23

2017

Dr. Steve Chesley

The Osiris Rex sample-return mission to the asteroid Bennu, a probable source of carbonaceous chondrites

Location: Geology 3656
Time: 2:30PM

The Osiris Rex mission was launched in September 2016. It will rendezvous with Asteroid Bennu in 2018 and spend 1.5 years mapping the surface. It will then sample the surface and return 60-2000 g to the Earth in 2023. It is the first US asteroid sampling mission.