Left-right asymmetry is the property of some objects in the universe that are not identical to their mirror images. This can be due to the object’s intrinsic properties, such as its chirality, or due to its interaction with other objects, such as a magnetic field.
The most familiar examples of left-right asymmetry are probably human hands: the left hand is a mirror image of the right hand, but it cannot be superimposed on it. Other examples include snail shells, which grow in a counterclockwise direction; and the DNA molecule, which has a left-handed helical structure.
Left-right asymmetry is thought to arise from broken symmetry in nature. In physics, symmetries are laws that govern how objects behave. They can be perfect symmetries, like those governing electromagnetic interactions, or they can be approximate symmetries, like those governing nuclear interactions. When a symmetry is broken, it means that there is no longer a law that requires objects to behave in a particular way.
One possible explanation for the observed left-right asymmetry in nature is that it results from the breaking of an underlying symmetry during the early history of the universe. This theory suggests that there was once a time when all matter was exactly symmetric with respect toleft-right reversal. But at some point during the universe’s history, this symmetry was spontaneously broken andmatter became slightly more likely to exist in one state than another. Over time, this tiny difference grew untilthe present day where we see significantleft-rightasymmetry throughout nature.