Oct

16

2016

Prof. Hilke Schlichting

Planets around other Stars

Location: Slichter 3853
Time: 2:30PM

Recent observations by the Kepler space telescope have led to the discovery of more than 4000 exoplanets consisting of many systems with Earth- to Neptune-sized objects that reside well inside Mercury-like orbits around their respective host stars. Hilke Schlichting will discuss how and where these close-in planets formed and will highlight some of the planets residing in the habitable zone, like Promina Centauri b. She will conclude with summarizing our prospects for learning more about these systems in the near future and for assessing their suitability to harbor life. Photo credit: NASA/JPL

Sep

18

2016

Prof. Kevin McKeegan

Calcium-Aluminum-rich Inclusions: The Solar System’s First Rocks

Location: Slichter 3853
Time: 2:30PM

Chondritic meteorites are cosmic sediments that contain many distinct nebular products. In addition to chondrules and matrix, some chondrites have several percent of inclusions that are rich in Ca, Al, and other refractory elements. These so-called CAIs are the oldest datable rocks thought to have formed in our solar system and they have many interesting properties. Kevin McKeegan will describe some CAIs, where they are found, and where they may have formed in the solar nebula.

Aug

28

2016

Alan Rubin

Comets - Icy Visitors from the Outer Solar System and a Major Source of Water and Carbon to the Earth

Location: Slichter 3853
Time: 2:30PM

Icy planetesimals that formed in the outer reaches of the solar system are occasionally perturbed closer to the Sun. In these warmer environs they emit gas and dust and form extensive tails. Comets have bewitched, bothered and bewildered observers since ancient times. One appeared in the sky after Caesar was assassinated in 44 BCE (interpreted as his soul ascending into Heaven); and one heralded Harold's demise and William the Conqueror’s success at the Battle of Hastings in 1066 CE. Comets may also have been responsible for delivering water, organics and other volatiles to Earth early in the history of our planet, setting the stage for the origin of life. Image credit: Alan Sailer

Jul

17

2016

Prof. An Yin

Geysers and Plate Motion on Saturn's Icy Moon Enceladus

Location: Slichter 3853
Time: 2:30PM

Saturn’s moon Enceladus has a radius of 500 km; it is the second nearest to Saturn of the larger satellites. The Cassini spacecraft discovered a series of “steam” geysers associated with a “tiger-stripe” terrain. The stripes appear to be boundary between blocks of ice tens of kilometers thick floating on a subsurface ocean. An Yin has carried out much research on the motions of crustal blocks on the Earth, and has applied the same approach to better understand the origin of the tiger stripes on Enceladus. The presentation will include photos of Saturn and its moons and rings and a discussion of possible explanations for the formation of the special features of Enceladus. Image credit: NASA/JPL-Caltech/Space Science Institute

Jun

19

2016

Nicholas Gessler

Oriented Meteorites: Nature’s Sculpture by Fire

Location: Slichter 3853
Time: 2:30PM

Meteorites enter the Earth’s atmosphere at speeds near 40,000 mph. These extreme velocities compress the air into a luminous hot plasma which envelopes them like a sheath. Most meteorites tumble during their fall; fragmentation is common. However a few exceptional ones maintain a stable orientation with one side continually facing forward (like space capsules). These oriented meteorites are sculpted into patterns of great beauty. Nick Gessler will discuss the physics and aesthetics of these rare rocks from space and focus on the newest addition to the UCLA Meteorite Gallery: a unique world-class oriented meteorite found near Baker, California.