Asteroids

Meteor astronomer Dr. Peter Jenniskens participated in a two-week Russian Academy of Sciences fact-finding mission to Chelyabinsk, just three weeks after the event, to collect data on the February 15 asteroid impact and the extent of the damage caused by its shock wave. Dr. Jenniskens will talk about his trip to Russia and give a report on the first hand accounts of the impact.

We know how to deflect asteroids, but our technology is useless if we do not scan the skies to look for asteroids to know well in advance if one is on a collision course with Earth.  The Sentinel Space Telescope, the first privately supported deep space mission, is designed to do just that and to enable humanity to protect our planet from future asteroid impacts.   Sentinel is an infrared space telescope to be placed into solar orbit in 201

Recently the current U.S. presidential administration directed NASA to include near-Earth asteroids (NEAs) as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. These missions would be the first human expeditions to interplanetary bodies beyond the Earth-Moon system and would prove useful for testing technologies required for human missions to Mars, Phobos and Deimos, and other Solar System destinations.

It is clear that the chondritic meteorites - those having essentially solar composition - carry unique information about the origin and early history of the solar system and the materials from which the planets formed. Yet it is a highly complex record that centuries of work and highly sophisticated modern techniques have not been able to decipher. Even the most fundamental issues, the origin of the chondrite classes and the origin of the chondrules that distinguish the meteorites from other materials, are still disputed.

On April 22, 2012, a 1/4 Hiroshima bomb detonation was heard in a wide area around Lake Tahoe. A small few meter sized asteroid crashed in our atmosphere, broke in fragments, pieces of which were seen falling down over the Colama/Lotus region by Doppler weather radar. This is right above Sutter's Mill, where the first gold was discovered by James Marshall on January 24, 1848. This led to the California Gold Rush that shaped our state as it is today.

In pairwise accretion -- that is, the formation of bigger planets hierarchically from smaller ones -- the typical encounter speeds are comparable to the escape velocities of the dominant bodies, and the colliding bodies are of comparable size. This is a far cry from the two most commonly considered regimes: hypervelocity bullets hitting a much larger target (a.k.a. impact cratering), and the perfect mergers (sometimes with a disruption threshold) assumed in nearly every N-body simulation of planetesimal/planetary growth. The best studied case is the Moon's formation by a giant impact.

The early bombardment history of the Inner Solar System is recorded in a number of interesting places (e.g., the surprisingly high abundance of highly siderophile abundances found in the Earth, Moon, and Mars, the observed impact basins found on Mercury, the Moon and Mars, various properties of main belt asteroids and meteorites, etc.).

Whether residing in low-earth orbit or traveling through interplanetary space, spacecraft must shield against environmental threats that could result in minor to catastrophic failure. One such threat is an impact by a meteoroid, which is a natural object ranging from 62 microns to meters in diameter that could cause either mechanical or electrical damage. In this presentation, Dr. Close will discuss current research into meteoroid and meteoroid plasma physics and how these tiny particles may offer insight into the formation of life on Earth.

The Deep Impact Flyby Spacecraft flew past comet Hartley 2 on 4 November 2010. Yet again a cometary flyby has led to numerous surprises that will yet again change our understanding of the role of comets in the formation of the solar system and our understanding thereof. This talk will highlight the new knowledge gained from the flyby. By the time of this talk, Stardust NExT will have flow past comet 9P/Tempel 1 (on 15 April PST) and the new data on the cometary nucleus onto which Deep Impact delivered its Impactor Spacecraft 5 years ago.

Near-Earth Asteroids (NEAs) are both enemies (that can collide with our planet) and friends (future targets for human exploration missions). As the Spaceguard Survey nears its goal of finding 90% of NEAs larger than 1 km, public and government interest turns to the much more numerous sub-kilometer NEAs. These small asteroids are the most likely to hit Earth and are also the designated NASA target for astronaut visits in the late 2020s.