#biosignatures

#biosignatures

While much of the history of life on Earth is written, the opening chapters are murky at best. On our ever-changing world, the older a rock is, the more it has changed, obscuring or even erasing evidence of ancient life. Beyond a hazy boundary of circa two billion years, in fact, this interference is so total that no pristine, unaltered Earth rocks are known to exist, making any potential sign of biology as clear as mud. At least until now.