Dust particles have been found in Earth’s atmosphere that are older than not only the planet, but the solar system itself.
An international team of scientists, led by Hope Ishii, director of advanced electron microscopy centre at the University of Hawaii, spotted this so-called interstellar dust in the upper parts of Earth’s atmosphere. Its chemical composition suggests how far the particles have travelled and the team concluded that the fine grains must be much older than our 4.6 billion-year-old solar system.
“Our observation suggests these exotic grains represent surviving pre-solar interstellar dust that formed the very building blocks of planets and stars,” Ishii said. “If we have, at our fingertips, the starting materials of planet formation from 4.6 billion years ago, that is thrilling and makes possible the processes that have formed and since altered them.”
We already know that most of the carbon and ice from before the solar system has either been destroyed or consumed into planets, but those substances do still exist as parts of comets. By taking the space dust from comet particles collected by a NASA stratospheric aircraft and analysing it using infrared light and electron microscopes, the team was able to observe the presence of GEMs (glass with embedded metal and sulphides) in the particles.
“The presence of specific types of organic carbon in both the inner and outer region of the particles suggests the formation process occurred entirely at low temperatures,” Jim Ciston from the Lawrence Berkeley National Laboratory and one of the researchers, said.
According to the paper, published in PNAS, the particles were clumped together in a cold environment, rich with radiation. The fact the grains existing in the dust at all is proof the silicates may not have been formed in the solar nebula from high-temperature gas at all. Instead, these particles could actually predate the solar system.
The scientists even suggest that some kind of sticky organic substance might be responsible for the particles clumping together to form the planets we have today.
Ishii and her team hope to investigate these particles further and unlock more of the secrets of the solar system’s birth. If it’s true that cold outer material is what created planets, then this discovery is huge for understanding how our planets came to be.