Scientists discover ancient interstellar dust that formed the Earth and the solar system

Doyle Rice | USA TODAY

It may not have been far, far away, but it certainly is from long, long ago.

Scientists have discovered some of the original interstellar dust that formed the Earth and the solar system billions of years ago, a new study said.

The discovery is the "surviving pre-solar interstellar dust that formed the very building blocks of planets and stars," said study lead author Hope Ishii of the University of Hawaii at Manoa.

Researchers collected the surviving ancient dust from Earth’s upper atmosphere, where it was likely deposited from comets. 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.

"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 Ciston of the Lawrence Berkeley National Laboratory in California.

The "dust" is actually tiny glassy grains called GEMS, or glass embedded with metal and sulfides — typically less than 1/100th the thickness of a human hair.

Referring to our current understanding of how planets form, after reading the new study, astrophysicist Ethan Siegel said "our naive picture of a disk that gets very hot, fragments, and cools to then form planets may be hopelessly oversimplified. Instead, we've learned that it may actually be cold, outer material that holds the key to our planetary backyard." Siegel, who was not part of the research, wrote about the study in Forbes.

Lead author Ishii said that "if we have at our fingertips the starting materials of planet formation from 4.6 billion years ago, that is thrilling and makes possible a deeper understanding of the processes that formed and have since altered them," she said.

Siegel called it "an enormous discovery....If the conclusions stand the test of time, we may have just revolutionized our understanding of how all planetary systems come into being."

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