14 DAY TRIAL // The origins of our Solar System seem to be far more varied than previously thought.
Scientists reached this conclusion after analyzing dust fragments from Comet Wild-2, captured by NASA's Stardust spacecraft and brought to Earth in January 2006.
As comets are among the oldest objects in the Solar System, the team assumed that samples of comet dust can reveal to us how Solar System formed.
To investigate the mineral composition of the dust, researchers employed spectroscopy technology which does not harm the mineral content of the particles and found a very diverse composition, not a single dominant one.
This means that the dust formed in many different ambients before entering in the composition of the comet, thus a great mixing in the early Solar System before the formation of planets.
The most conclusive was the presence of calcium aluminum inclusions, one of the oldest solids in the Solar System, which formed close to the young Sun.
The results reveal that the comet components originated from all over the early Solar System, with some dust having formed close to the Sun and other material coming from the further asteroid belt between Mars and Jupiter.
Because Wild-2 originally formed in the outer Solar System, some of its materials have traveled great distances.
"We weren't expecting to find such widely-spread material in the sample of dust we were given to examine. The composition of minerals is all over the place, which tells us that the components that built this comet weren't formed in one place at one time by one event. It seems that the Solar System was born in much more turbulent conditions than we previously thought." said Dr Phil Bland of Imperial's Department of Earth Science and Engineering.
NASA's 2005 Deep Impact mission which brought images of material blasted from the nucleus of the comet Tempel 1 revealed evidence of water presence within the comet.
The dust from Wild-2 does not reveal any current or past water presence.
"This is a very interesting mismatch, and it seems that comets are not all the same. Perhaps they vary as much in their evolution as in the composition of the dust from which they are made." said Anton Kearsley of the Natural History Museum.
"Comets are likely to be the oldest objects in our Solar System and their components have remained largely unchanged, so discovering more about what they have experienced gives us a snapshot of the processes that formed the planets over four and a half billion years ago. Fundamentally we still don't know how you make planets from a cloud of dust and gas. Hopefully the Wild-2 samples will help us towards an answer." added Bland.