Scientists have directly observed the rocky guts of exoplanets, which are worlds from different star systems, by watching the fallout of these objects crashing into the corpses of dead stars. From a report: This mind-boggling technique has revealed that exoplanets are similar in composition to planets in our own solar system, implying that worlds like Earth may be plentiful in our galaxy, according to a study published on Thursday in Science. “It’s pretty cool because this is really the only way to measure the geochemistry of exoplanetary bodies directly,” said lead author Alexandra Doyle, a graduate student of geochemistry and astrochemistry at UCLA, in a phone call. Co-author Edward Young, a professor of geochemistry and cosmochemistry at UCLA, added that the study represents “the first time such an advanced way of looking at the geochemistry of these bodies has been used,” in the same call.

We are living through a golden age of exoplanet discoveries. Thousands of exoplanets have been detected, including an Earth-sized world orbiting the closest star to the Sun. But it is still extremely difficult to capture details about the interior composition and dynamics of these worlds. Unlike other planetary properties such as mass or atmospheric composition, a planet’s geochemistry cannot be deduced just by looking at an object passing in front of its host star. White dwarfs, as it turns out, can help plug this information gap. These objects are the remains of stars that have blown up and collapsed into tiny, dense spheres about the size of Earth (our own Sun will embark on this transition in about five billion years). The pyrotechnic deaths of these stars scramble the orbits of many objects in our solar system, such as asteroids and planets. Some of these worlds may end up hurtling toward the star’s posthumous white dwarf, which tears them apart over the course of about 100,000 to one million years.

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