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Sciences and Exploration Directorate

Exploration
at Goddard

At Goddard, exploration is a system that builds outward, grounded in understanding Earth, extending through the space environment, and enabling safe and sustained missions to the Moon, Mars, and beyond.

The Sciences and Exploration Directorate (SED) brings together complementary scientific disciplines that work in concert to make exploration possible. Each contributes in a distinct way, while collectively forming a unified exploration enterprise.

Hover to see how our science makes exploration possible
ASTRONOMY PICTURE OF THE DAY

Spokes on Saturn's B Ring

Don’t get spooked by Saturn’s ghostly spokes! Today we feature a nearly two-hour timelapse of Saturn and its rings looping forwards and backwards. If you look closely, a ghoulish shadow appears and disappears as  Saturn’s B ring  rotates. Decades of observation with  Voyager 2,  Cassini, and Hubble  show the appearance of Saturn’s spokes varies with  the planet’s seasons. Like Earth, Saturn’s  spin axis  is tilted compared to the plane of its orbit around the Sun. During Saturn’s  equinox, the rings are  less tilted  toward the Sun and they receive sunlight at a shallower angle. Saturn’s spokes may be electrically charged dust and ice temporarily levitated above the rings by electromagnetic forces. It is still uncertain, but the ring plasma and charge environment may be influenced by changing ultraviolet illumination, meteoroid impacts, or indirect effects from interactions between the solar wind and the planet’s magnetic field. Note: The text of this APOD has been revised. Find dark skies and look up this August to witness the Perseid meteor shower uninhibited by the Moon!

Earth Observatory Picture

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HEASARC

Picture of the Week