A two-kilometers-wide asteroid — large enough to cause continent-wide devastation on Earth — could strike the planet on February 1, 2019, based on astronomers’ preliminary orbit calculations, BBC News reports. The uncertainty of the forecast is large, however — several tens of millions of kilometers, according to Dr. Donald Yeomans of NASA JPL.

Invisible comets made of an exotic material called “mirror matter” could also be on a collision course with Earth, says University of Melbourne physicist Dr. Robert Foot in a new book, Shadowlands: Quest for Mirror Matter in the Universe.

He cites “missing” comets and asteroids that disappear after their first pass through our solar system and puzzling events such as the devastating Tunguska Siberia explosion that flattened 2100 square kilometers of forest with the explosive power of 1000 atomic bombs in 1908, with no crater, no evidence of meteorite fragments and no significant chemical traces.

Space rock ‘on collision course,’ BBC News report, July 24, 2002

Ghostly asteroids clue to missing matter, University of Melbourne news release, July 23, 2002