Lightest-ever aerogel is only twice as heavy as hydrogen

In a Nature paper called "Solid carbon, springy and light, scientists from Zhejiang University in Hangzhou, China introduce a record-breakingly light aerogel, lighter than helium, only twice as heavy as hydrogen:

Gao Chao's team had already been building macroscopic graphene materials in one and two dimensions; to create the new aerogel, the researchers branched out into the third dimension, using a new method of freeze drying the solutions of carbon nanotubes and graphene to create malleable carbon sponges.
PhD candidate Sun Haiyan explained, "It's somewhat like large space structures such as big stadiums, with steel bars as supports and high strength film as walls to achieve both lightness and strength. Here, carbon nanotubes are supports and graphene is the wall."
The new material is amazingly absorptive, able to suck in up to 900 times its own weight in oil at a rate of 68.8 grams per second — only oil, not water, which means it has massive potential as a cleaning material when it comes to events such as oil spills.

Graphene aerogel is the new world's lightest substance