First synthesized in 2012, aerographite earned its place as the world's lightest solid. Its ultra-low density and unique properties make it ideal for photonic sails on probes designed to swiftly exit our Solar System, as noted by leading astronomers.
Composed of intertwined carbon nanotubes, aerographite—or carbon aerogel—achieves a remarkable density of just 180 g/m³, roughly seven times lower than air (1,225 g/m³). German researchers unveiled it in 2012, publishing their findings in the prestigious journal Advanced Materials.
Beyond its lightness, aerographite excels in near-perfect light absorption, reflecting fewer than one photon in a thousand. It also serves as an excellent electrical conductor, paired with a spongy, highly elastic structure.
Potential applications span electrodes for lithium-ion batteries, synthetic fibers for clothing, air and water purification, and even tackling oil spills by absorbing up to 900 times its weight in oil. In space exploration, however, its attributes shine brightest.
Aerographite's lightness and darkness position it perfectly for photonic sails. Illuminated by a laser or sunlight, a probe fitted with such a sail could accelerate efficiently. Scientists envision a 1 m diameter, 0.5 mm thick sail launched from the ISS reaching Mars in just 60 days or Pluto in 4 years.
Scaling up to a 10 m diameter sail enables a 55 g payload and effortless Solar System escape. This could launch the first interstellar probe toward Alpha Centauri, site of Proxima Centauri b—a likely rocky exoplanet in its star's habitable zone, 4.25 light-years away (roughly 40 billion kilometers).
