Pic of the Day (27th Oct)

[Event Horizon]

Full size Image

The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep.

The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Recently, several geologic processes have been identified in the canyon. The above mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s.

 

[Event Horizon]

Yes some of the markings on the surface are still considered to be evidence of massive water flow at one time in the past. The main fissure you are looking at is thought to have been created a very long time ago by the rapid cooling of the crust. Water in solid form is still thought to be present in abundance especially around the polar regions

 

[Event Horizon]

I have tried to find the best i can Its especially amazing when you consider that this photo was taken in 1970!