Earth and other planets in our solar system have existed longer than previously thought, according to a new study of asteroid debris in a distant star system.
A study published November 14 in Nature Astronomy looks at the oldest stars in the universe and suggests that stars and planets grew together. It was previously believed that planets would not form until the star reached its full size.
The sun formed from a cloud of gas 4.6 billion years ago, and the planets formed around it.
“We know pretty well how the planets formed, but one question that remains is ‘when?’ Is it while the parent star is still growing? , or millions of years later?” said Dr Amy Bonser of Cambridge University’s Institute of Astronomy.
Antennas of the Large Millimeter and Submillimeter Interferometer (ALMA) Atacama radio telescope project. Located on the Chajnantor plateau in San Pedro de Atacama, Chile, about 1,500 kilometers north of Santiago (Getty Images)
Using the Large Atacama Millimeter-Submillimeter Interferometer in Chile, the researchers probed the atmosphere of a white dwarf (the remnant of a Sun-like star) looking for planetesimals, the building blocks of planets. “Some white dwarfs surprised the lab because their thin atmospheres were like cemeteries in the sky,” Bonser said.
The white dwarfs studied are unique because their atmospheres are contaminated with heavy elements such as magnesium, iron and calcium. According to the authors, these elements must have come from asteroids born during planet formation that later collided with white dwarfs and melted in their atmospheres.
According to the paper, the process by which lighter elements float to the surface and iron sinks to the core is the reason why the Earth has an iron-rich core.
The planet is generally believed to have formed in rings of hydrogen, helium, and ice and dust particles orbiting young stars. Dust particles combine to form planetesimals, which over time grow into asteroids or planets.
This study suggests that planetesimals form almost instantaneously. “If these asteroids were melted into something that only existed for a short time at the beginning of the planetary system, the planet formation process must start very quickly,” said Bonser. “Our work supports the growing consensus in the field that the formation of planets began early and that the first bodies formed at the same time as stars.”
Wishes for clear skies and big eyes.
(original forbes.com)
