What On Earth Is Wrong With Gravity?
The Power of Gravity Helps Shape the Universe

What On Earth Is Wrong With Gravity?
The Power of Gravity Helps Shape the Universe

Particle physicist Dr Brian Cox wants to know why the Universe is built the way it is. He believes the answers lie in the force of gravity.

But Newton thought gravity was powered by God, and even Einstein failed to completely solve it.

Heading out with his film crew on a road trip across the USA, Brian fires lasers at the moon in Texas, goes mad in the desert in Arizona, encounters the bending of space and time at a maximum security military base, tries to detect ripples in our reality in the swamps of Louisiana and searches for hidden dimensions just outside Chicago.

Brian Cox is a British particle physicist, a Royal Society University Research Fellow and a professor at the University of Manchester. Particle physicist Dr Brian Cox wants to know why the Universe is built the way it is. He believes the answers lie in the force of gravity.

Gravity, is one of the four fundamental interactions of nature (along with the strong force, electromagnetism and the weak force), in which objects with mass attract one another.

In everyday life, gravitation is most familiar as the agent that gives weight  to objects with mass and causes them to fall to the ground when dropped. Gravitation causes dispersed matter to coalesce, thus accounting for the existence of the Earth, the Sun, and most of the macroscopic objects in the universe.


Einstein and the World's Most Famous Equation

The history behind how this equation could be invented..and who all played their role in inventing this wonderful and powerful equation which can destroy the world or also make the whole world glow.

Gravitation is responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth; for the formation of tides; for natural convection, by which fluid flow occurs under the influence of a density gradient and gravity; for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena observed on Earth.

Modern physics describes gravitation using the general theory of relativity, in which gravitation is a consequence of the curvature of spacetime which governs the motion of inertial objects. The simpler Newton's law of universal gravitation provides an accurate approximation for most calculations.

In general relativity, the effects of gravitation are ascribed to spacetime curvature instead of a force. The starting point for general relativity is the equivalence principle, which equates free fall with inertial motion, and describes free-falling inertial objects as being accelerated relative to non-inertial observers on the ground.

In Newtonian physics, however, no such acceleration can occur unless at least one of the objects is being operated on by a force.

Einstein proposed that spacetime is curved by matter, and that free-falling objects are moving along locally straight paths in curved spacetime. These straight paths are called geodesics.

Like Newton's first law of motion, Einstein's theory states that if a force is applied on an object, it would deviate from a geodesic. For instance, we are no longer following geodesics while standing because the mechanical resistance of the Earth exerts an upward force on us, and we are non-inertial on the ground as a result.

This explains why moving along the geodesics in spacetime is considered inertial. Einstein discovered the field equations of general relativity, which relate the presence of matter and the curvature of spacetime and are named after him. The Einstein field equations are a set of 10 simultaneous, non-linear, differential equations.

The solutions of the field equations are the components of the metric tensor of spacetime. A metric tensor describes a geometry of spacetime. The geodesic paths for a spacetime are calculated from the metric tensor.

Einstein's Messengers

Ripples in the fabric of space-time from monumental collisions between black holes, and how scientists are trying to measure them with lasers and mirrors.

The discovery and application of Newton's law of gravity accounts for the detailed information we have about the planets in our solar system, the mass of the Sun, the distance to stars, quasars and even the theory of dark matter.

Although we have not traveled to all the planets nor to the Sun, we know their masses.

These masses are obtained by applying the laws of gravity to the measured characteristics of the orbit.

In space an object maintains its orbit because of the force of gravity acting upon it. Planets orbit stars, stars orbit Galactic Centers, galaxies orbit a center of mass in clusters, and clusters orbit in superclusters. The force of gravity is proportional to the mass of an object and inversely proportional to the square of the distance between the objects.