Posted on

Could Cassini See You On “The Day The Earth Smiled?”

So along with the rest of the world, you smiled. You waved. You went outside on July 19, wherever you were, and looked upwards and out into the solar system knowing that our robotic representative Cassini would be capturing a few pixels’ worth of photons bouncing off our planet when they eventually reached Saturn, 900 million miles away. But did Cassini actually capture any photons coming from where you were? The image above will tell you.

Assembled by the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo (where the enormous 305-meter radio telescope is located) this image shows what side of Earth was facing Cassini when its “pale blue dot” images were obtained, at approximately 22:47 UTC (Cassini time.)

Didn’t make it into Cassini’s photo? That’s ok… maybe MESSENGER had already caught you earlier that very same day:

The view of Earth seen by MESSENGER from Mercury on July 19, 2013
The view of Earth seen by MESSENGER from Mercury on July 19, 2013

Before Cassini took its images — several hours before, in fact — the MESSENGER spacecraft was holding some photo shoots of its own from 61 million miles in the other direction!

The image above shows the side of Earth that was facing Mercury on the morning of July 19, 2013, when MESSENGER was acquiring images in our direction during a hunt for any possible satellites of the innermost planet.

Earth was as bright (-4.8 magnitude) as the maximum brightness of Venus at the moment the image was taken from Mercury.

Of course, in both series of images specific details of our planet can’t be made out — Earth was barely more than a pixel in size (regardless of any bloom caused by apparent brightness.) Clouds, countries, continents, oceans… the entire population of our world, reduced to a single point of light — a “mote of dust suspended in a sunbeam.”

For both portrayals, high-resolution black and white images from the GOES East and Meteosat meteorological satellites were combined with color information from NASA Visible Earth to generate true-color images of our planet as it would have looked to each respective imaging spacecraft… if they had the impossibly-precise optics to resolve Earth from such distances, of course.

But it’s ok that they don’t… we can still use our imaginations.

Read more here on the PHL’s news release.

Earth from the geostationary weather satellite GOES East on July 19, 2013 at 5 PM EST. This is approximately the view that Cassini would have had of Earth during imaging.
Earth from the geostationary weather satellite GOES East on July 19, 2013 at 5 PM EST. This is approximately the view that Cassini would have had of Earth during imaging.

Image credits: PHL @ UPR Arecibo, NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington, NERC Satellite Station, Dundee University, Scotland. Thanks to Prof. Abel Méndez (PHL/UCR) for the heads-up on these.

Posted on

What the Earth and Moon Look Like From Saturn

Did you smile and wave at Saturn on Friday? If you did (and even if you didn’t) here’s how you — and everyone else on Earth — looked to the Cassini spacecraft, 898.4 million miles away.

Hope you didn’t blink!

The image above is a color-composite made from raw images acquired by Cassini in red, green, and blue visible light wavelengths. Some of the specks around the edges are background stars, and others are the result of high-energy particle noise,  of which some have been digitally removed.

The Moon is the bright dot just below and to the left of Earth. (An original raw image can be seen here.)

UPDATE 7/22: See the *official* NASA images here.

Cassini acquired the images while capturing views of Saturn in eclipse against the Sun between 22:24:00 UTC on July 19 and 02:43:00 UTC on July 20 (6:24 to 10:43 pm EDT July 19.) On Cassini time, the Earth imaging took place between 22:47:13 UTC (6:47:13 pm EDT) and 23:01:56 UTC (7:01:56 pm EDT) on the 19th.

Full mosaic arrangement acquired by Cassini on July 19-20 UTC. (NASA/JPL-Caltech/SSI)
Full mosaic arrangement acquired by Cassini on July 19-20 UTC. Earth was positioned just below the planet. (NASA/JPL-Caltech/SSI)

The world was invited to “Wave at Saturn” beginning 5:27 pm EDT on Friday — which allowed enough time for the photons from a waving world to actually reach Cassini’s camera just beyond Saturn, 1.44 billion kilometers away. (Did you wave? I did!) It was the first time Earth’s population was made aware beforehand that their picture would be taken from such a cosmic distance.

A crowd gathered on the mall at NASA's Jet Propulsion Laboratory in Pasadena to wave at Saturn on July 19 (NASA/JPL-Caltech)
A crowd gathered on the mall at NASA’s Jet Propulsion Laboratory in Pasadena to wave at Saturn on July 19 (NASA/JPL-Caltech)

The image of our planet and moon, seen as merely a couple of bright points of light against the blackness of space, recalls Sagan’s poignant “pale blue dot” passage from Cosmos…

“From this distant vantage point, the Earth might not seem of any particular interest. But for us, it’s different. Consider again that dot. That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The "pale blue dot" of Earth captured by Voyager 1 in Feb. 1990 (NASA/JPL)
The “pale blue dot” of Earth captured by Voyager 1 in Feb. 1990 (NASA/JPL)

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

Posted on

Waltz Around Saturn With This Beautiful Animation

In honor of this today’s Wave at Saturn and The Day the Earth Smiled events, celebrating images to be taken of Earth from Saturn, here’s a wonderful movie showing highlights from Cassini’s exploration of the giant planet, its magnificent rings, and fascinating family of moons.

Assembled by Fabio Di Donato in memory of astrophysicist, author and activist Margherita Hack, who passed away June 29 at the age of 91, this video is an impressive tour of the Saturnian system — and a truly stunning tribute as well.

“She made me love the stars,” Fabio wrote.

This video shows a selection from more than 200,000 pictures taken by the Cassini spacecraft around Saturn’s rings in a period between 2005 and 2013. RAW images were processed to PNG thanks to the Vicar-to-PNG procedure provided by Jessica McKellar.

The music is Jazz Suite No.2: VI Waltz 2 by Shostakovich, performed by the Armonie Symphony Orchestra.

As always, you can see the latest images and news from the Cassini mission here, and find out how your photo is going to be taken from 900 million miles away (and also 60 million miles away from Mercury!) here.

Video: Fabio Di Donato. Original images: NASA/JPL-Caltech/SSI.

P.S.: Want to get a personalized certificate saying you “Waved at Saturn?” Click here.