Images of Saturn and Earth

Just over a week ago the Cassini spacecraft was deliberately crashed into Saturn at the end of it’s extended mission orbiting the gas giant planet.

Saturn and its magnificent rings

NASA:  Cassini Spacecraft Ends Its Historic Exploration of Saturn

Cassini launched in 1997 from Cape Canaveral Air Force Station in Florida and arrived at Saturn in 2004. NASA extended its mission twice – first for two years, and then for seven more. The second mission extension provided dozens of flybys of the planet’s icy moons, using the spacecraft’s remaining rocket propellant along the way. Cassini finished its tour of the Saturn system with its Grand Finale, capped by Friday’s intentional plunge into the planet to ensure Saturn’s moons – particularly Enceladus, with its subsurface ocean and signs of hydrothermal activity – remain pristine for future exploration.

While the Cassini spacecraft is gone, its enormous collection of data about Saturn – the giant planet, its magnetosphere, rings and moons – will continue to yield new discoveries for decades to come.

Just prior to this:  Cassini Spacecraft Makes Its Final Approach to Saturn

NASA’s Cassini spacecraft is on final approach to Saturn, following confirmation by mission navigators that it is on course to dive into the planet’s atmosphere on Friday, Sept. 15.

Cassini is ending its 13-year tour of the Saturn system with an intentional plunge into the planet to ensure Saturn’s moons – in particular Enceladus, with its subsurface ocean and signs of hydrothermal activity – remain pristine for future exploration. The spacecraft’s fateful dive is the final beat in the mission’s Grand Finale, 22 weekly dives, which began in late April, through the gap between Saturn and its rings. No spacecraft has ever ventured so close to the planet before.

Some of the last images taken by Cassini:

Saturn Hemisphere

Saturn’s northern hemisphere with rings in the background

Enceladus

One of Saturn’s moons, Enceladus, on the horizon
(Saturn has 62 confirmed moons)

 

Saturn Rings

Saturn’s rings

Saturn's rings and our planet Earth

An earlier (2013) photo of Earth from Saturn

And zooming in a bit closer:

New Earthrise Image from LRO spacecraft

A view of earth from NASA’s Lunar Reconnaissance Orbiter (LRO)

Image Credits: NASA/JPL-Caltech/Space Science Institute

‘Ingredients for life’ on Saturn moon

NASA reports: Ingredients for Life at Saturn’s Moon Enceladus

NASA’s Cassini spacecraft discovered hydrogen in the plume of gas and icy particles spraying from Saturn’s moon Enceladus.

The discovery means the small, icy moon — which has a global ocean under its surface — has a source of chemical energy that could be useful for microbes, if any exist there. The finding also provides further evidence that warm, mineral-laden water is pouring into the ocean from vents in the seafloor.

On Earth, such hydrothermal vents support thriving communities of life in complete isolation from sunlight.

Enceladus now appears likely to have all three of the ingredients scientists think life needs:

  • liquid water,
  • a source of energy (like sunlight or chemical energy),
  • and the right chemical ingredients (like carbon, hydrogen, nitrogen, oxygen).

Cassini is not able to detect life, and has found no evidence that Enceladus is inhabited. But if life is there, that means life is probably common throughout the cosmos; if life has not evolved there, it would suggest life is probably more complicated or unlikely than we have thought.

Either way the implications are profound.

Future missions to this icy moon may shed light on its habitability.

White smoker footage courtesy of: NOAA-OER / C.German (WHOI)

Saturn has 62 diverse moons (with confirmed orbits) so there is plenty of scope for a variety of conditions, including conditions including the ingredients of life.

Enceladus is the sixth largest moon of Saturn, about 500 kilometres in diameter (Earth’s Moon has a diameter of 3474 km).

280px-pia17202_-_approaching_enceladus

Photo of Enceladus taken from Cassini

If life was able to become established and thrive on Earth then it’s logical to assume it could and will have happened elsewhere, but it’s cool to find evidence of where it could actually happen within our own solar system.