Third ever picture of Earth from Outer Solar System to be taken tomorrow night

MeteoritesEire · 18-07-2013 9:18pm #1

A Nasa spacecraft exploring the rings of Saturn will shoot a portrait of Earth on July 19.

In 2006, the Cassini spacecraft saw Saturn eclipse the sun. These eclipses are rare, but another is due to happen on July 19, 2013.

We humans have acquired only two images of Earth from the outer solar system – ever. Soon we’ll have a third, thanks to a Saturn eclipse that’s coming up on July 19, 2013. On that day, as the sun’s brilliant light is blocked by Saturn, Cassini will attempt to get the third-ever photo of Earth taken from the outer solar system.
The shot, taken 898million miles away by the Cassini-Huygens spacecraft, will frame the whole Saturn system backlit by the Sun. In the distance, peeking over the edge of our star, Earth will also be captured on camera.

Between 22:27 and 22:42 Irish time on July 19, Nasa is encouraging earthlings to go outside and wave at the far-away planet.

But this photography session is not just an excuse for a jolly. Scientists are looking at the more diffuse (spread out) rings that encircle Saturn and how they are changing over time.

The last time Cassini shot the Saturn system was in 2006. That portrait revealed that the planet’s dusty E ring had oddly large variations in brightness and colour around its orbit.

Seven Earth years and one Saturnian season later, researchers will be studying images of this ring to try and understand the system’s solar radiation levels and magnetic field.

As well as using the imaging cameras to do this, data will be collated from a visual and infrared mapping spectrometer, composite infrared mapping spectrometer and ultraviolet imaging spectrograph.

Meanwhile, sitting on the surface of Titan, one of Saturn’s moons and the largest single expanse of unexplored terrain remaining in the solar system today, is the Huygens probe. Delivered by Cassini in January 2005, the probe houses instruments from The Open University, including multiple sensors to determine the physical properties of Titan’s surface and measure the physical and electrical properties of the atmosphere.

According to Professor John Zarnecki of the OU’s Planetary and Space Sciences Research Institute, the Huygens probe has enabled scientists to examine Titan’s atmosphere – which has some similarities to Earth’s primitive atmosphere four billion years ago – and ‘go back in time to see some aspects of the Earth’s origins.’

‘It’s hard to believe our experiment is still sitting up there serenely on the surface of Titan having performed far longer than we ever expected, providing lots of data for us to analyse,’ says Zarnecki.

‘But the prospect of seeing images taken by Cassini of the whole Saturnian System and of Earth is enthralling.’

On July 19 the image generated by Cassini will be the first to capture our planet in its natural colour, as human eyes on Saturn would see it.

The only other spacecraft to shoot an image of Earth from the outer solar system was Nasa’s Voyager 1. The craft photographed us 23 years ago from a distance of four billion miles.

Launched in 1997, Cassini entered Saturn orbit in 2004. Its mission is planned to end in 2017 – long enough to observe a half-cycle of Saturn’s seasons.

ps200306 · 19-07-2013 8:30am

I was lucky enough to spend a week with Zarnecki and other OU luminaries two summer's ago on an observational astronomy course in Spain. Some interesting campfire stories (although I didn't get to ask anything about Huygens). My meagre claim to fame is I helped him figure out heavens-above.com

That's him third from right, and that's me ... well, that's me very near him.

Standard Toaster · 19-07-2013 9:35am

What's the light travel time from Earth to Saturn ?

MeteoritesEire · 19-07-2013 9:45am

Standard Toaster wrote: »

What's the light travel time from Earth to Saturn ?

Saturn is between 8 and 11 times farther than the sun and the suns light takes 8 minutes to reach us so
8 to 11 times 8 minutes depending on orbital location

LeinsterDub · 19-07-2013 9:50am

MeteoritesEire wrote: »

Saturn is between 8 and 11 times farther than the sun and the suns light takes 8 minutes to reach us so
8 to 11 times 8 minutes depending on orbital location

Shouldn't that technically be 7 to 10? As the Earth is 1 unit from the sun to begin?

Standard Toaster · 19-07-2013 10:00am

This link says it's 1.33 Light Hours from Earth

mickmackey1 · 19-07-2013 10:14am

LeinsterDub wrote: »

Shouldn't that technically be 7 to 10? As the Earth is 1 unit from the sun to begin?

No, the 1 unit is included in the 8 to 11.

Bohrio · 19-07-2013 10:20am

I think that it depends on earth positions too

Saturns Apheleon

Distance 1,513,325,783 km
Time 1 h 24 m and 17 sec

Periphelion
Distance 1,353,572,956 km
Time 1 h 15 m 15 sec

Current distance Saturn - Earth
Distance 1,444,621,760 km
Time 1 h 20 m 18 sec

dbran · 19-07-2013 12:52pm

Saturn Rises today 19/7/13 at 14.44 and sets 00.57 (tomorrow morning) low in the sw at 10.27.

ciaranmac · 19-07-2013 12:56pm

LeinsterDub wrote: »

Shouldn't that technically be 7 to 10? As the Earth is 1 unit from the sun to begin?

The planets aren't strung out in a neat line like in a science book though. For half of each year the earth is further from the sun than from Saturn.

dbran · 19-07-2013 1:02pm

Standard Toaster wrote: »

What's the light travel time from Earth to Saturn ?

80.31 light minutes tonight per Sky Safari

MeteoritesEire · 19-07-2013 4:35pm

ciaranmac wrote: »

...... For half of each year the earth is further from the sun than from Saturn.

not true

Popoutman · 20-07-2013 5:05pm

ciaranmac wrote: »

The planets aren't strung out in a neat line like in a science book though. For half of each year the earth is further from the sun than from Saturn.

You meant to say for about half the year, Earth is farther from Saturn than Saturn is from the Sun..

King George VI · 20-07-2013 7:16pm

When do we get to see the pic?

coylemj · 20-07-2013 10:19pm

ciaranmac wrote: »

For half of each year the earth is further from the sun than from Saturn.

The Earth is never further from the Sun than it is from Saturn.

I think what you meant to say is that for half the year (when Saturn is close to the Sun in the sky i.e. below the horizon at midnight), the distance between the Earth and Saturn is up to 2AU greater than it is when Saturn is at opposition.

blah blah whatever · 21-07-2013 2:05am

MeteoritesEire wrote: »

Between 22:27 and 22:42 Irish time on July 19, Nasa is encouraging earthlings to go outside and wave at the far-away planet.

Well budgie, no one told me!

Images will be up here sometime.

Other people who were waving.

Hal1 · 21-07-2013 4:06pm

The RAW image: http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS79/N00213958.jpg

Edited with noise removed: http://www.flickr.com/photos/lightsinthedark/9329557951/

I've seen better pics of saturn taken from earth. Might aswell have been taken with a mobile.

coylemj · 21-07-2013 11:15pm

Hal1 wrote: »

I've seen better pics of saturn taken from earth. Might aswell have been taken with a mobile.

Given the age of the technology and how they test stuff to death before sending it up in a space mission (so it's usually already out of date at launch time), you're probably closer to the mark than you think.

But the picture is of Earth taken from Saturn (currently 1,450 million kms away) so it was never going to be anything other than a picture of the Sun with the Earth as a faint nearby dot.

Rubeter · 22-07-2013 6:36am

Hal1 wrote: »

The RAW image: http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS79/N00213958.jpg

Edited with noise removed: http://www.flickr.com/photos/lightsinthedark/9329557951/

I've seen better pics of saturn taken from earth. Might aswell have been taken with a mobile.

Did you think we sent one of these out to Saturn?