The study of asteroids helps us understand more about early Solar System history.


Jane Houston Jones: What's Up for March? Bright Saturn and a faint asteroid named Lutetia. Hello and welcome! I'm Jane Houston Jones at NASA's Jet Propulsion Laboratory in Pasadena, California. This month Saturn is at Opposition, which is when the sun is on one side of the Earth and Saturn is directly on the opposite side.

Title - Saturn on February 18, 2010

Jones: Saturn is brightest at Opposition. And it's also as close to Earth as it ever gets in its orbit. You can view Saturn all night long now. It rises in the east at sunset and sets in the west at dawn.

Title - Looking East mid-month late evening

Jones: If you face east in the late evening, you can see two planets near the distinctive constellation Leo. First, look nearly overhead. That reddish object you see up there is Mars. Closer to the horizon, the bright golden-hued object is Saturn. Saturn is well-placed for viewing from now through July.

Title - The changing tilt of Saturn's rings as seen from Earth

Jones: This year, Saturn's rings are slightly inclined. They were tilted 4 degrees in January. They'll dip to nearly edge-on in June and then tip up to 10 degrees by year-end. The Solar System was a violent place to start with. There were many crashes in which small bodies broke into pieces and re-formed. The study of asteroids helps us understand a lot more about the early Solar System history.

Title - Animation. Asteroids are actually much farther apart.

Jones: Of the millions in our Solar System, only a few have been observed up close. Near the middle of the constellation Leo is the challenging-to-see and faint main-belt asteroid 21 Lutetia. You'll need a good star chart and a medium to large telescope plus dark skies to glimpse this small twelfth-magnitude asteroid. Jones: If you don't see Lutetia, that's OK, because the European Space Agency's

Title - Rosetta spacecraft and artist's concept of asteroid

Jones: Rosetta spacecraft will pay a second visit to this interesting object in July, passing within 3000 kilometers of the asteroid. Rosetta had its first look at Lutetia in January of 2007.

Title - OSIRIS: Optical, Spectroscopic and Infrared Remote Imaging System

Jones: The OSIRIS camera imaged the asteroid passing through its field of view during the spacecraft's approach to Mars for a gravity assist. Rosetta's instruments will collect enough information to create a resumé of the asteroid's past: where it was born, how it got started on its asteroid career and if there were any mid-course corrections.

Title - Cassini spacecraft at Saturn. Titan. Iapetus. Enceladus

Jones: The Cassini spacecraft has been studying Saturn, its rings and moons since arriving in 2004.

Title - Saturn at Winter Solstice. Oct. 30, 2002

Jones: Cassini's seven-year Solstice Mission extension, to the year 2017, presents an opportunity to follow the seasonal changes of an outer planet

Title - Saturn at Equinox. Aug. 9, 2009

Jones: all the way from its winter

Title - Saturn at Summer Solstice. May 23, 2017

Jones: to its summer.

Title - Cassini Solstice Mission. 2010 - September 2017

Jones: During its 155 orbits around Saturn, including 55 flybys of the moon Titan, Cassini will fly by the icy moon Enceladus 11 more times.

Title -

Jones: You can learn more about Cassini and other NASA missions at

Title -

Jones: The NASA contribution to ESA's Rosetta Mission can be found at

Title - Thanks to the following for submitting images: European Space Agency, Morris Jones, Anthony Wesley

Jones: That's all for this month. I'm Jane Houston Jones.

Title - NASA, Jet Propulsion Laboratory, California Institute of Technology

View all Videos