Mirror Symmetry!?
Do you know?
Before 1956, the majority of
the science community believed that nature is mirror-symmetric.
In other words, physical phenomena occurring in front
of a mirror (for instance, spinning along a certain direction)
or behind a mirror (in this case spinning in the opposite
way) were considered equally probable.
However, Chinese-born American physicists Yang Chen-Ning
and Lee Tsung-Dao thought otherwise. They designed sophisticated
experiments to test their hypothesis and proposed them
to another Chinese physicist, C.S. Wu, who later confirmed
their prediction of symmetry breakown in the beta decay
experiment of cobalt. For this important contribution,
Yang and Lee became the first two Chinese Nobel Laureates
in 1957.
Experiments revealed that the decay probabilities of right-spinning
and left-spinning Cobalt atoms were different. This phenomenon
of symmetry breakdown is called the Violation of the Principle
of Parity Conservation. Today, many scientists believe
that we are living in a universe made primarily of matter,
instead of one comprising equal amounts of matter and
anti-matter. This may be attributed to the violation of
parity conservation. The building block of all lifeforms
on Earth is the deoxyribonucleic acid (DNA). It has the
shape of a double helix in which two polynucleotide chains
are coiled about each other in a spiral. Curiously, this
structure is not mirror-symmetric in the sense that most
DNA found in nature is right-handed. |
