Atom & Cosmos

Clearing out space junk with dust, plus new black holes, sonic-boom star birth and more in this week’s news

Dust to clean up space junk Scientists have devised a controversial way to get rid of small space junk —material about 10 centimeters wide that can harm spacecraft. Gurudas Ganguli of the Naval Research Laboratory in Washington, D.C., and his colleagues propose removing the material by sprinkling about 20 tons of fine tungsten dust in a thin shell around the Earth.