In case you haven’t heard, an interplanetary photo op takes place today (July 19, 2013) that should result in the third-ever photo of Earth from the perspective of an outer planet. Saturn will be in eclipse at the time as seen by the Cassini spacecraft, which has been orbiting Saturn since 2004. Space scientists expect a beatiful image of Saturn and its rings, plus the pale blue dot of Earth. NASA’s Messenger orbiter will also be snapping photos of the Earth and moon, from its vantage point in orbit around the planet nearest our sun.

Carolyn Porco, head of the Cassini mission’s imaging team, and others on the Cassini team want you to participate in this event. Porco calls it:

… a global moment of cosmic self-awareness.

All you have to do, as Cassini cameras are trained our way, is smile.

The time for the cosmic smile toward Saturn will be a 15-minute interval that begins at 5:27 p.m. EDT, 4:27 CDT, 3:27 MDT, 2:27 p.m. PDT (21:27 UTC). Beginning then, and for 15 minutes, the light reflected by your smile and wave will make the journey from Earth to Saturnian orbit – a journey of nearly 1 billion miles – in time to be captured by Cassini’s camera about 80 minutes later.

See the first two photos of Earth from Saturn, here.

Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said:

Cassini has photographed Earth before, but this will be the first time Earthlings know in advance their picture will be taken from a billion miles away. We hope that people around the world will go outside to wave at Saturn while the photo-shoot is underway.

Cassini has been orbiting Saturn since 2004. So why are photos of Earth from Saturn so rare? Most of the time, when Cassini looks toward Earth, it is also looking toward our solar system’s central sun. The sun’s light drowns Earth from view. On July 19, circumstances will be such that, from Cassini’s point of view, the body of Saturn will eclipse the sun. Saturn’s rings will appear magnificently backlit. Earth will appear as a tiny blue speck just outside the E ring.

This photo-shoot will improve upon Cassini’s previous efforts in two ways: The July 19, 2013, image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini’s highest-resolution camera.

The Americas will be facing Saturn at the time of the image. For North Americans, the event happens in broad daylight, so the best way to participate is to go outside, face east, and wave at the blue sky. You won’t be able to see Saturn, but it is there.

Can you see Saturn at night now, by the way? You surely can. By nightfall, Saturn will have moved into the southwestern sky. It’ll pops out in the twilight, a slightly-golden pinprick about twice as bright as the sky’s brightest stars. As it’s been for a couple of years now, Saturn appears near on the sky’s dome to the bright star Spica in the constellation Virgo. Just don’t mistake Venus for Saturn. Venus is much, much brighter and low in the west after sunset.

Spilker said:

Seeing the whole mosaic of the backlit rings when it is put together will be incredible. We will be looking for changes in Saturn’s faint rings, especially the E ring, from the mosaic we took back in 2006.

Space scientist Carolyn Porco – who is Cassini imaging team leader – added:

It will be a day to celebrate life on the Pale Blue Dot.

Bottom line: Today, NASA’s Cassini spacecraft will be photographing Earth through the rings of Saturn. It’ll be the third-ever photo of Earth taken from the outer solar system, and you can join the shot. The time is Friday, July 19 @ 2:27 p.m. PDT (5:27 P.M. EDT). NASA has already accounted for the light-travel time to Saturn, so don’t worry about it. Go outside and add your photons to the portrait of Earth that will be created by NASA’s Cassini spacecraft, now orbiting Saturn. For more information, Carolyn Porco’s website The Day Earth Smiled. It’s on Facebook at https://www.facebook.com/events/650683051626720/. And follow the event or express how you feel about it on Twitter, #DayEarthSmiled.