Chinese scientists have developed the world's lightest substance - it is so light that a mug-size of it wouldn't even bend a blade of grass.
Developed by scientists at Zhejiang University, carbon aerogel has a density of 0.16 mg/cubic centimetre - one-sixth of that of air.
Aerogel is a material produced with semi-solid gel dried and solvent removed. It appears in a solid state with many internal pores filled with air, and thus it's of minimal density.
The research team led by Professor Gao Chao freeze-dried solutions of carbon nanotubes and graphene to remove moisture and retain integrity.
Carbon aerogel is also a "super sponge" - one of the materials with biggest oil absorption capacity. The feather-light gel can absorb up to 900 times its weight.
"Carbon aerogel is expected to play an important role in pollution control, for oil spills, water and even air purification," Gao Chao said.
The study was published in the journal Advanced Materials.