Scientists find ancient dust that formed Earth

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 presolar interstellar dust that formed the very building blocks of planets and stars,” said lead author Hope Ishii of the University of Hawaii at Manoa.

Researchers collected the 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 studied.

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

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.

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

HOPE ISHII An electron micrograph of an interplanetary dust particle that likely came from a comet.