Particles from early solar system found in comet dust

Particles from early solar system found in comet dust

The researchers were able to collect them from Earth's upper atmosphere where they were deposited after being brought along by comets each time they fly near the sun.

An worldwide team of researchers has found minute particles of interstellar dust that date back to the origin of Solar System some 4.6 billion years ago. As comets pass near the sun, they release dust that can reach Earth's orbit and settle through the atmosphere, where it can be collected and later studied with electron microscopes.

After the collapse of the presolar molecular cloud, these first-generation metal-impregnated GEMS aggregated with crystalline grains that were likely transported from the hot inner-solar nebula, creating second-generation aggregates, which were then likely incorporated into small, icy cometary bodies. The team says that the GEMS formed inside the interstellar medium via grain shattering, amorphization, and erosion from supernovae shocks.

The presolar dust particles in question are actually called GEMS - or "glass embedded with metal and sulfide".

The researchers conclude by noting that their picture is incomplete, and much of the data is still rough-for instance, the elemental composition of GEMS sometimes only matches the solar elemental composition collectively, exhibiting chemical anomalies at higher resolution.

The study was published Monday in the peer-reviewed journal Proceedings of the National Academy of Sciences.

The initial solids from which the solar system formed consisted nearly entirely of carbon, ices, and disordered (amorphous) silicate, the team concluded. Scientists discovered grains called GEMS, which are believed to originate from comets, might be a dusty relic from before the formation of our solar system.

Using transmission electron microscopy, Ishii and colleagues made maps of the element distributions and discovered that these glassy grains are made up of subgrains that aggregated together in a different environment and prior to the formation of the comet parent body.

Ishii, who is based at the UH Manoa's Hawaii Institute of Geophysics and Planetology, said, "Our observations suggest that these exotic grains represent surviving pre-solar interstellar dust that formed the very building blocks of planets and stars". The latter, as the researchers said, was low in density and decomposed even with the slight amount of heating - a fact that suggested that the GEMS may have formed in a cold environment like in the outer solar nebula, after trapping the leftover dust.

The co-author of the study James Clinton of the Lawrence Berkeley National Laboratory in California has said that these interplanetary dust particles can survive from the time which is before the formation of the planetary bodies in the solar system and it provides the insight into the chemistry of those ancient building blocks.

This dust was mostly destroyed and reworked by processes that led to the formation of planets.

Related Articles