What does Earth have in common with different planetary systems hundreds of light years away? A lot, according toresearchers.
Astronomers measured the composition of 18 galaxies up to 456 light years away that feature many elements in proportions
comparable to those found on our own globe.
“Most of the building blocks we have looked at in other planetary systems have a composition broadly similar to that of the Earth,” according to researcher Siyi Xu, of the Gemini Observatory in Hawaii, who presented the work at this week’s Goldschmidt Conference on geochemistry in Boston.
One of the largest examinations of its kind, this study allows scientists to better understand how far-off planetary systems are forged. Oh, and maybe lead us to finding Earth-like bodies elsewhere in the universe.
Planets orbiting other stars were first discovered as recently as 1992. Over the 26 years that followed, researchers have been trying to gauge whether any of the spheres are akin to this solar system.
“It is difficult to examine these remote bodies directly,” Xu explained. “Because of the huge distances involved, their nearby star tends to drown out any electromagnetic signal, such as light or radio waves. So we needed to look at other methods.”
So, the team turned to white dwarf stars, which pull in material from planets, asteroids, comets, and other orbiting cosmic objects—some of which form a dust disk, like the rings of Saturn.
As material approaches, it changes the star’s spectroscopic signal, making it easier to identify the type and quantity of material surrounding the white dwarf.
“These measurements can be extremely sensitive,” Xu said, “allowing bodies as small as an asteroid to be detected.”
The team took measurements using spectrographs on Hawaii’s Keck telescope—the largest optical and infrared scope in the world—and the Hubble Space Telescope. They collected details about the volume of calcium, magnesium, and silicon, among other elements, in the stars.
While Xu’s work is on-going—and will certainly benefit from the recent release of data from the GAIA satellite—his initial study suggests Earth is “pretty normal.”
“And that means that we can probably expect to find Earth-like planets elsewhere in our galaxy,” he added.