268
PHVSICS OF THE IMPOSSIBLE
other words, the basic laws of physics haven't changed for billions of
years, and they are constant out to the outer edges of the universe.
At a minimum, I realized, Noether's theorem means that the conservation of energy will probably last for billions of years, if not forever. As far as we know, none of the fundamental laws of physics have
changed with time, and this is the reason that energy is conserved.
The implications of Noether's theorem on modern physics are profound. Whenever physicists create a new theory, whether it addresses
the origin of the universe, the interactions of quarks and other subatomic
particles, or antimatter, we first start with the symmetries that the system
obeys. In fact, symmetries are now known to be the fundamental guiding principle in creating any new theory. In the past, symmetries were
thought to be by-products of a theory-a cute but ultimately useless feature of a theory, pretty, but not essential. Today we realize that symmetries are the essential feature that defines any theory. In creating new
theories, we physicists first start with symmetry, and then build the theory around it
(Sadly, Emmy Noether, like Boltzmann before her, had to fight
tooth and nail for recognition. A woman mathematician, she was denied a permanent position at leading institutions because of her sex.
Noether's mentor, the great mathematician David Hilbert, was so frustrated in failing to secure a teaching appointment for Noether that he
exclaimed, "What are we, a university or a bathing society?")
This raises a disturbing question. If energy is conserved because
the laws of physics do not change with time, then could this symmetry
be broken in rare, unusual circumstances? There is still the possibility
that the conservation of energy might be violated on a cosmic scale, if
the symmetry of our laws is broken in exotic and unexpected places.
One way that might happen is if the laws of physics vary with time
or change with distance. (In Asimov's novel The Gods Themselves this
symmetry was broken because there was a hole in space connecting
our universe with a parallel universe. The laws of physics change in
the vicinity of the hole in space, therefore allowing a breakdown in the
laws of thermodynamics. Hence the conservation of energy could be
violated if there are holes in space, that is, wormholes.)
PHVSICS OF THE IMPOSSIBLE
other words, the basic laws of physics haven't changed for billions of
years, and they are constant out to the outer edges of the universe.
At a minimum, I realized, Noether's theorem means that the conservation of energy will probably last for billions of years, if not forever. As far as we know, none of the fundamental laws of physics have
changed with time, and this is the reason that energy is conserved.
The implications of Noether's theorem on modern physics are profound. Whenever physicists create a new theory, whether it addresses
the origin of the universe, the interactions of quarks and other subatomic
particles, or antimatter, we first start with the symmetries that the system
obeys. In fact, symmetries are now known to be the fundamental guiding principle in creating any new theory. In the past, symmetries were
thought to be by-products of a theory-a cute but ultimately useless feature of a theory, pretty, but not essential. Today we realize that symmetries are the essential feature that defines any theory. In creating new
theories, we physicists first start with symmetry, and then build the theory around it
(Sadly, Emmy Noether, like Boltzmann before her, had to fight
tooth and nail for recognition. A woman mathematician, she was denied a permanent position at leading institutions because of her sex.
Noether's mentor, the great mathematician David Hilbert, was so frustrated in failing to secure a teaching appointment for Noether that he
exclaimed, "What are we, a university or a bathing society?")
This raises a disturbing question. If energy is conserved because
the laws of physics do not change with time, then could this symmetry
be broken in rare, unusual circumstances? There is still the possibility
that the conservation of energy might be violated on a cosmic scale, if
the symmetry of our laws is broken in exotic and unexpected places.
One way that might happen is if the laws of physics vary with time
or change with distance. (In Asimov's novel The Gods Themselves this
symmetry was broken because there was a hole in space connecting
our universe with a parallel universe. The laws of physics change in
the vicinity of the hole in space, therefore allowing a breakdown in the
laws of thermodynamics. Hence the conservation of energy could be
violated if there are holes in space, that is, wormholes.)