Glassy galaxies

Clouds of sand crystals resembling crushed glass envelop 21 infrared-bright galaxies, astronomers report.

Observed by NASA’s infrared Spitzer Space Telescope, the silicate crystals are the first recorded beyond the Milky Way. The galaxies that the crystals coat are known as ultraluminous infrared galaxies and are the product of a collision of two or more spiral galaxies.