Hey Planet Earth! Get Ready to Smile and Wave for a Camera That’s a Billion Kilometers Away

by Nancy Atkinson on July 12, 2013

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This graphic shows the view of Earth and the portion of its surface that will be illuminated during the Earth imaging event by the Cassini spacecraft on July 19, 2013. Credit: NASA/JPL-Caltech.

This graphic shows the view of Earth and the portion of its surface that will be illuminated during the Earth imaging event by the Cassini spacecraft on July 19, 2013. Credit: NASA/JPL-Caltech.

July 19, 2013 will be a day that we should really all try to get along. Isn’t that a noble goal? And you can be a part of it in several different ways. In a special project, the Cassini spacecraft will be taking an image of Earth, from the spacecraft’s orbit around Saturn. Specifically, Cassini will be on the far side of Saturn when it snaps a picture of “us” between 21:27 to 21:42 UTC (5:27-5:42 pm EDT.) Cassini will be in just the right spot that it can “see” Earth, but Saturn will be blocking the glare from the Sun. There will likely be a dramatic view of Saturn and its rings in the foreground, with Earth off in the distance. Our home planet won’t be much more than a few pixels in the image, but it will be “us, …everyone you love, everyone you know, everyone you ever heard of, every human being who ever was,” as Carl Sagan said about the Pale Blue Dot image taken by the Voyager spacecraft.

“It will be a day to revel in the extraordinary achievements in the exploration of our solar system that have made such an interplanetary photo session possible,” said Cassini imaging team leader Carolyn Porco of the Space Science Institute, who had the idea for this special image. “And it will be a day for all of us to smile and celebrate life on the Pale Blue Dot.”

The event is called The Day The Earth Smiled, and this is very cool for several reasons.

Voyager 1 pale blue dot. Image credit: NASA/JPL

Voyager 1 pale blue dot. Image credit: NASA/JPL

First, while Earth has been imaged before from other distant spacecraft (the famous Pale Blue Dot image and Cassini has taken pictures of Earth before) this is the first time that many of the inhabitants of Earth will know the image is being taken – hence the invitation to smile and wave.

Second, Saturn is now visible in the night sky — bright and shining — allowing us a direct line of sight to smile and wave back. No, we can’t see Cassini, but we know it’s there!

Plus, there’s other special chances to submit your own images – of Saturn, and of Earth, or of yourself in the moments Cassini is taking the image.

For all our astrophotographer friends out there, in cooperation with Astronomers Without Borders, TDTES is sponsoring a Saturn Mosaic project, where you can submit an image you’ve taken of Saturn. Urgency note: this has to be submitted by July 22, 2013.

Astronomers Without Borders is also sponsoring a special Saturn Observing Program, and they are encouraging people and organizations to either organize a special observing event for July 19 (you can register it as an official event here) or to attend an event near you. You can find TDTES events here. This can be a full-blown observing event with telescopes, or just an excuse to get together with friends to go out and look at Saturn in the night sky.

There are also two competitions — one is to submit photos that best represents Earth (the image must be taken on July 19, 2013) and another is to write an original song about this event. The digital versions of the winning entries will be beamed to space at a later date.

Find more information at The Day The Earth Smiled website, and the Astronomers Without Borders website.

NASA also has some charts on where and when to look for Saturn in the night sky here. NASA says these charts take into account the light travel time from Saturn.

And don’t forget to smile and think about all the good things about our world.

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

Other_events July 13, 2013 at 2:01 AM

“Saturn is visible in the night sky”…or not, depending on your location. So, for some of us, smiling and waving at the ground just won’t seem the same. Hmmm… Perhaps a direct line of sight photo of the ground at the exact time could be quirky enough to win the competition.

Astroraider July 19, 2013 at 12:06 AM

Yeah … most of the wave at Saturn events politely ignore the light travel time …

If you wave at Saturn when the spacecraft actually shoots the image, you will be at least an hour (and more) late … it takes light more than a hour to travel to Saturn … so … you will be missed.

Just like Star Trek … NASA has politely but incorrectly ignored light travel time and time problems … everything happened instantaneously but … oh wait … lightspeed is such a drag … so it wasn’t included … If James Kirk left earth and traveled around the galaxy at warp 2 (and he traveled a lot faster most of the time) … hmmm … in five years … time dialation would have meant that everybody he knew when he left would have been dead for decades if not centuries or millenia depending on the direction traveled!

Oh but SNAP … NASA forgot to mention that there is a definite light lag to Saturn so if the Cassini Probe photographs earth

… You would need to do it earlier so that your photons would actually REACH Saturn during the photo period … hmmm … dunno where Saturn is in the orbit … It is probably superfluous anyway since there is no possibility that the resolution is sufficient to determine if people are out waving or not.

Based on today … 1,444,858,322 km at speed of light at
300,000 km/s … that comes to about 1.33 hours or about 1 hour 21 minutes

And the distance is growing … so it would be slightly longer later …

So based on this information, I would need to stand outside
and wave roughly estimated (based on NASA 21:27 to 21:42 UTC) … about 20:05 to
20:17 UTC or … 1:05 to 1:17 p.m. PST or about 3:05 to 3:17 p.m. EST – maybe up
to 5-10 minutes earlier … as I said the distance is growing.

Do the math correctly please

DOH!!!

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