Walking is good for you, but here's why walking backward might be even better. Just try not to fall. Or laugh.

All known natural life uses L (left-handed) amino acids in proteins and D (right-handed) sugars in DNA and RNA. In contrast, mirror life would use D proteins and L sugars — effectively a reversed ...

Kate Adamala started work on a cell in which the natural molecular structure is reversed. Then a possible doomsday scenario became clear.