https://phys.org/news/2018-11-stardust.html > Yet that space you are peering into is not nearly as empty as you think. The space around the celestial bodies is teeming. The space between those stars and planets – the interstellar medium – is filled with gas and dust. All that material floats aimlessly through space, until it clumps together to form new stars and planets. But what that substance consists of precisely is still largely unknown. > Sascha Zeegers from the Leiden Observatory and the Netherlands Institute for Space Research (SRON) offers a look behind the scenes in her thesis: she discovered that the constituent dust she researched consists largely of olivine, olive-green gemstones probably produced by stars. "We rather expected to encounter this silicate," says Zeegers. "But it is unique that we have been able to measure it so clearly."