Scientist discovered prehistoric interstellar dust which formed Earth and Solar System

Mindy Sparks
June 14, 2018

This is likely how these particles ended up in Earth's upper atmosphere: via a comet-based delivery system. The team collected them from Earth's upper atmosphere, probably brought along each time comets pass near the sun.

An global team, led by Hope Ishii, a researcher at the University of Hawaii at Manoa (UH Manoa), studied the particles' chemical composition using infrared light at Berkeley Lab's Advanced Light Source (ALS). However, scientists posited that most of these particles may have been consumed in the process, while the rest could have been trapped in small, icy cold bodies forming in the outer nebula. The team says that the GEMS formed inside the interstellar medium via grain shattering, amorphization, and erosion from supernovae shocks.

The work revealed that the particles contained tiny grains of glass embedded with metal and sulfides. Scientists also explored their nanoscale chemical makeup using electron microscopes at the Lab's Molecular Foundry, which specializes in nanoscale R&D, and at the University of Hawaii's Advanced Electron Microscopy Center.

It has always been believed that the initial solids or dust that led to planetary formation contained particles like amorphous silicate, carbon and ices.

The study was published online June 11 in the journal Proceedings of the National Academy of Sciences.

The researchers note that the complex organics in the ice-mantled grains must have experienced a high-radiation environment before incorporation into larger bodies, which may have resulted from vertical diffusion of dust above the solar system's mid-plane.

The researchers discovered their glassy grains were made up of smaller "subgrains" that collected together before their host comets formed. This aggregate is encapsulated by carbon of a different type than the carbon that forms a matrix gluing together GEMS and other components of cometary dust.

Because the type of carbon found in the inner region of the GEMS would not withstand the temperatures of the solar nebula, the scientists concluded that these particles were formed in a cooler environment in two separate stages of aggregation. "Our observations suggest that these exotic grains represent surviving pre-solar interstellar dust that formed the very building blocks of planets and stars", Hope Ishii, one of the authors behind the latest work, said in another statement.

"These interplanetary dust particles survived from the time before formation of the planetary bodies in the solar system, and provide insight into the chemistry of those ancient building blocks", said study co-author James Cliston of the Lawrence Berkeley National Laboratory in California.

As per lead author Ishli, she said that if we have to do at our fingertips then the starting materials of the planet formation are from about 4.6 billion years ago and it is thrilling, and it makes it possible to go deeper to understand the processes which have formed.

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