Damian Peach
Astrophotographer Damian Peach captures Siding Spring (green smudge at lower-centre) on approach to Mars (saturated star-like object)

bbc.com

A recently discovered comet has whizzed past Mars, giving scientists a unique chance to study an object from the farthest reaches of the Solar System.

The comet, known as Siding Spring, raced past Mars at 56km per second (125,000mph), missing it by 139,500 km. Rovers on the Martian surface and satellites were primed to catch the event on their cameras and instruments.

Siding Spring comes from the Oort Cloud – a spherical region of space far beyond the planets.

Researchers believe the comet is very little altered from the time of its formation more than 4.5 billion years ago.

“Siding Spring probably got knocked into the inner Solar System by the passage of a star near the Oort Cloud,” said Carey Lisse, from the Johns Hopkins University Applied Physics Laboratory, US.

“So think about a comet that started to travel probably at the dawn of man and it’s just now coming in.

“And the reason we can actually observe it is because we’ve built satellites and rovers and we’ve now got these outposts at Mars. That’s pretty exciting.”

Martin Mobberley /Siding Spring Martin Mobberley used a remote telescope at the Siding Spring Observatory itself to image the comet
Nick Howes Siding Spring 
The comet is dead-centre of this image from Nick Howes and coleagues