One of the most famous images taken by NASA's Cassini spacecraft is of Saturn as it eclipses the Sun. With the gas giant bathed in shadow, a tiny speck called Earth can be seen in the photo.
This week, NASA announced that Cassini will be recreating that famous photo. On July 19, the probe will take the picture as part of a mosaic being composed using Cassini pictures. Though the Earth will appear as only a pale blue dot roughly the size of one pixel, NASA is encouraging people in North America and parts of the Atlantic Ocean (which will be in sunlight at the time) to wave to the sky at around 2:30 pm to acknowledge the occasion.
"While Earth will be only about a pixel in size from Cassini's vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL). "We hope you'll join us in waving at Saturn from Earth, so we can commemorate this special opportunity.
In addition to providing a new photo of the Earth from Saturn, Cassini will be studying the planet's ring during the 15 minutes it will spend in its shadow. The probe will be taking both visible- and infrared-light images of Saturn's rings to gather data for researchers.
"Looking back towards the sun through the rings highlights the tiniest of ring particles, whose width is comparable to the thickness of hair and which are difficult to see from ground-based telescopes," said Matt Hedman, a Cassini science team member at Cornell University. "We're particularly interested in seeing the structures within Saturn's dusty E ring, which is sculpted by the activity of the geysers on the moon Enceladus, Saturn's magnetic field and even solar radiation pressure."