Science › Creation theories
A zero-energy universe
1973· Theory
SpeculativeA serious idea with no experimental proof yet.
The idea that the positive energy of all matter is exactly balanced by the negative energy of gravity, so the universe's total is zero.
See it on the Science map →How it works
Pulling two masses apart takes work, so matter held together by gravity has negative gravitational energy. Add up all the mass-energy in the universe (positive) and all its gravitational energy (negative), and rough estimates come out close to cancelling. If they cancel exactly, creating the universe costs nothing. Inflation fits neatly: as space grows, the driving field's total energy grows, and gravity's negative share grows by the same amount. Alan Guth called the universe 'the ultimate free lunch'.
Why it matters
It removes the most obvious objection to creation from nothing: that it would break conservation of energy. The universe also shows no net electric charge and no overall rotation.
Think of it like
Like a building bought entirely with a loan: a large asset on one side, an equal debt on the other, and net equity of zero.
How we know
The universe is measured flat to within about 0.2% (Planck satellite, 2018), which in simple models means the energies balance. But general relativity has no agreed way to total the energy of a whole universe.
Still a mystery
Critics say 'zero total energy' is partly a matter of definitions: automatic for a closed universe, undefined for an infinite one. Whether it explains anything physical is debated.
Connections (3)
▸The universe as a vacuum fluctuation relies on A zero-energy universeSpeculative
The relationship
A fluctuation carrying real net energy would vanish almost instantly. For a universe to last 13.8 billion years, its net energy must be essentially zero, with matter's positive energy cancelled by gravity's negative energy. Tryon argued this cancellation holds in a closed universe, so his proposal stands or falls with it. Other conserved totals, such as electric charge, must also be zero.
How the link was found
Tryon made the argument in his 1973 Nature paper, drawing on earlier estimates that the universe's gravitational and mass energy roughly balance.
Is it proven?
Both halves are unproven: that the universe has zero total energy, and that zero-energy fluctuations can last indefinitely. Both are consistent with a flat or nearly flat universe.
Open questions and mysteries
Is a closed universe, which Tryon needed, the one we live in? Measurements cannot yet tell a very large closed universe from a flat one.
▸A zero-energy universe squares creation with Conservation of energySpeculative
The relationship
Conservation of energy says totals never change. A universe from nothing seems to break that rule, going from zero to a vast amount of energy. If gravity's negative energy exactly cancels matter's positive energy, the total stays at zero throughout, so creation needs no outside input. The books balance at every moment, including the first.
How the link was found
Pascual Jordan suggested in the 1940s that a star could arise from nothing this way. George Gamow recalled that when he told Einstein, Einstein stopped in the middle of a street. Tryon applied it to the universe in 1973.
Is it proven?
Plausible but unproven. In general relativity, energy conservation holds locally, but a total for the whole universe is defined only in special cases, so 'zero' may be a definition rather than a discovery.
Open questions and mysteries
Creation from nothing needs every conserved total to start at zero, not just energy. Electric charge seems to, but matter far outnumbers antimatter: was that excess made later, as baryogenesis theories propose?
▸General relativity: gravity is curved spacetime gives gravity negative energy in A zero-energy universeSpeculative
The relationship
In Einstein's theory, mass-energy curves spacetime, and the bookkeeping of that curvature acts like negative energy. For a closed universe, Einstein's equations impose a strict condition: matter energy and gravitational energy must sum to exactly zero at all times. For an open, infinite universe there is no agreed way to total it at all.
How the link was found
Richard Feynman remarked in his 1962–63 Caltech lectures on gravitation that rough estimates put the universe's total energy near zero. The exact closed-universe result follows from Paul Dirac's and Arnowitt, Deser and Misner's reformulations of relativity (1958–62).
Is it proven?
The closed-universe zero is a mathematical identity accepted by relativists. Critics say that makes it trivial rather than deep. Whether our universe is closed is unknown.
Open questions and mysteries
By Einstein's equivalence principle, gravity has no energy you can pin to a single place. Is 'negative gravitational energy' then real physics, or an accounting convention?