Science Facts

  A physics hypothesis called the Big Bang event explains how the cosmos grew from a highly dense and hot starting condition.  The evolution of the observable universe from the earliest known times to its succeeding large-scale shape is explained by several cosmological theories of the Big Bang.  A wide range of observable phenomena, such as the quantity of light elements, the cosmic microwave background (CMB) radiation, and large-scale structure, are all thoroughly explained by these theories. Cosmic inflation, or the abrupt and extremely fast expansion of space during the Universe's early moments, provides an explanation for the uniformity of the Universe as a whole, sometimes known as the "flatness issue."  Yet there isn't yet a generally recognised quantum gravity theory in physics that can accurately simulate the Big Bang's early circumstances. Precise studies of the universe's expansion rate establish the Big Bang singularity at an estimated 13.7870.020 ...

  Gravity, which derives from the Latin word gravitas, which means "weight", is a basic interaction in physics that causes all objects with mass or energy to attract one another.  The electromagnetic force, the weak interaction, and the strong interaction are all significantly stronger than gravity, which is by far the weakest of the four fundamental interactions.  As a result, it has no appreciable impact on subatomic particle level phenomena. Yet, at the macroscopic level, gravity is the most important interaction between things and governs the motion of planets, stars, galaxies, and even light. The Moon's gravity causes sublunar tides in the oceans, just as gravity on Earth imparts weight to physical objects (the corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another).  In addition, gravity plays a significant role in many biological processes, including gravitropism, which directs plant growth, and the movement of fluids ...

  Time dilation is defined in physics and relativity as the difference in elapsed time as measured by two clocks. It is caused by either a difference in relative velocity (special relativistic "kinetic" time dilation) or a difference in gravitational potential between their locations (general relativistic gravitational time dilation). When left undefined, "time dilation" usually refers to the effect of velocity. Because of time dilation, two working clocks will report different times after different accelerations. Time moves slower on the ISS, for example, lagging approximately 0.01 seconds for every 12 Earth months. GPS satellites must compensate for similar bending of spacetime in order to properly coordinate with systems on Earth.