Is momentum conserved in general relativity?
Is momentum conserved in general relativity?
At low velocities, relativistic momentum is equivalent to classical momentum. Relativistic momentum approaches infinity as u approaches c. This implies that an object with mass cannot reach the speed of light. Relativistic momentum is conserved, just as classical momentum is conserved.
Why is energy momentum tensor symmetric?
In general relativity, the symmetric stress–energy tensor acts as the source of spacetime curvature, and is the current density associated with gauge transformations of gravity which are general curvilinear coordinate transformations. (If there is torsion, then the tensor is no longer symmetric.
Is the stress energy tensor always symmetric?
Symmetry of the stress-energy tensor The stress-energy tensor is a symmetric matrix. If we have a nonzero Ttx, it represents a flux of mass-energy (pt) through a three-surface perpendicular to x. This means that mass is moving in the x direction.
Does expanding universe violate conservation of energy?
Energy was conserved. As space expands, it releases stored up gravitational potential energy, which converts into the intrinsic energy that fills the newly created volume. So even the expansion of the universe is controlled by the law of energy conservation.
Does general relativity conserve energy?
The energy of a photon is given by Planck’s constant times its frequency, so as the frequency decreases over time the energy also decreases. Since the number of photons themselves remains constant this means that energy is being lost and hence energy cannot be conserved in general relativity.
What is meant by stress tensor?
The Stress Tensor Stress is defined as force per unit area. If we take a cube of material and subject it to an arbitrary load we can measure the stress on it in various directions (figure 4). These measurements will form a second rank tensor; the stress tensor.
Is the universe losing energy?
The Universe is slowly dying, according to astronomers who have made a study of the fall in energy levels resulting from the fusion of matter taking place in the nuclear furnaces of the stars of more than 200,000 galaxies.
Does the universe need energy to expand?
As more space comes into existence, more of this energy-of-space would appear. As a result, this form of energy would cause the universe to expand faster and faster.
