Physical time

If time is based on the decay or vibration of matter, and the speed of all physical changes is altered by gravity, then that alteration is time itself. Physically, a change in state is time.

If time is viewed as an 'independent and absolute entity,' then energy changes due to gravity are merely phenomena where the energy state of matter changes. However, if time is based on the decay or vibration of matter, and the speed of all physical changes is altered by gravity, then that alteration is time itself. Physically, a change in state is time. Atomic clocks aboard satellites run faster than those on Earth because the gravitational energy is lower. Even if different types of atomic clocks are used, since they are all calibrated based on the intrinsic frequency of atoms, the time correction value due to gravity remains identical. In modern physics, time is an inseparable axis within the four-dimensional space-time continuum. When gravity warps space, the 'interval' between all events occurring within that space changes; this change in interval is called 'time dilation'. If gravity only affected the reactions of specific substances, it would be a simple 'physical interference'. However, gravity distorts the very geometric structure of space itself. Even light, which has no mass, vibrates and moves along this curved space because gravity warps space itself. The space through which light moves is spacetime.




All energy responds identically to gravity. Within a gravitational field, spacetime curvature alters the energy state of matter. When an object is placed within this curved spacetime, it affects the total amount and distribution of the object's energy, causing its potential energy to change due to differences in positional energy. This change in energy signifies a mass-energy change, which affects the gravitational decay path or speed. This occurs because mass and energy are equivalent (E=mc^2), and the curvature of spacetime within a gravitational field alters the energy state of matter. As an object falls toward a mass, the potential energy of the system within the gravitational field decreases reducing its energy. When energy decreases, the total mass of the system also decreases according to the equivalence principle. That is, when an object moves under the influence of gravity, it is a process of mass-energy stabilizing into a lower energy state. All physical processes—atomic reactions, biological metabolism, light vibrations—change at the same rate due to gravity.




The energy of light is maintained without loss over distance in a vacuum. Since light does not interact with matter in a vacuum, it can travel forever without losing energy. Although light does not lose energy in a vacuum, it spreads out as distance increases, so the energy of light reaching a given area (Intensity) decreases inversely proportional to the square of the distance. This is due to 'spatial diffusion' rather than an inherent energy loss of light itself. In a vacuum, light does not lose energy, but its intensity weakens due to diffusion. When light travels extremely long distances in outer space, not a typical vacuum, the phenomenon of 'redshift' occurs where the wavelength lengthens due to the expansion of the universe. In this case, the energy of the light decreases.  





The decay rate of a radioactive element remains constant (half-life) regardless of whether it is in a vacuum. The radioactive decay of nuclides like uranium is an internal property of nucleons that is unaffected by the external environment (pressure, temperature, presence of matter). Placing it in a vacuum does not stop or accelerate decay; it decays identically according to the half-life. Uranium decay arises from the instability of the atomic nucleus; a vacuum merely means there are no interfering particles nearby and does not alter the mechanism. Since radioactive decay is a phenomenon governed by the nuclear force within the nucleus, gravity could theoretically alter the apparent rate of radioactive decay (and thus the energy release rate) through spacetime curvature. However, gravity acts on a macroscopic level that is far larger than the typical quantum scales (Planck Scale) to influence radioactive decay. If the difference in curvature between one side of a nucleus and the other is extreme enough (approaching the Planck Scale), it creates a physical stretch and disrupts the very physical processes that allow an atomic clock—which relies on the precise vibrations of atoms—to function.




If all physical changes within a gravitational field (such as uranium decay, light vibrations, or cellular aging) occur at the same rate, it is equivalent to physical time itself changing. However, gravity does not directly affect the nuclear processes of fission or fusion (the nuclear force). Time is difficult to define operationally, and a clock is not time itself. Gravitational changes (time dilation) measured at different locations are merely measurements at those specific points; their relative differences cannot be known without direct comparison. Relative changes due to gravity cannot be compared unless they meet; when they do meet, only the clock readings (physical quantities) differ.

---

Time, Einstein, and the Coolest Stuff in the Universe, Text Transcript
https://www.nist.gov/pao/time-einstein-and-coolest-stuff-universe-text-transcript

Time, Einstein, and the Coolest Stuff in the Universe, Text Transcript

This talk features Nobel Laureate in Physics and NIST Fellow Bill Phillips. At the beginning of the 20th century Einstein changed the way we think about Time.  
https://www.nist.gov/video/nist-frontiers-time-einstein-and-coolest-stuff-universe-bill-phillips

NIST Frontiers: Time, Einstein, and the Coolest Stuff in the Universe, by Bill Phillips

The Science and Society conference brought together world leading researchers and scholars in science and world affairs—individuals who have dedicated their careers to addressing the most complex and challenging problems of our time.
https://youtu.be/Z3jcd39rK1M?si=Ynil9Bcvmxey1lwf

Time, Einstein, and the Coolest Stuff in the Universe - W. Phillips - 2/26/2016

The universe does not simply exist in time. Time is something the universe continuously writes into itself.
https://theconversation.com/is-time-a-fundamental-part-of-reality-a-quiet-revolution-in-physics-suggests-not-273841

Is time a fundamental part of reality? A quiet revolution in physics suggests not