‘Unexplained’ molecule on Venus hints at life

Phosphine has been detected in Venus’s atmosphere, raising the thrilling question of whether the molecule might be a sign of life on the planet. On rocky planets, life is the only known source of the compound — although it forms without a helping hand near the energetic cores of the gas giants. Life seems impossible on the surface of the Solar System’s hottest world, but the middle of its cloud layer offers a more promising environment in terms of temperature, pressure and presence of water and organic molecules. Even if it’s not a sign of life on Venus, the unexpected observation is exciting.