String Theory and Loop Quantum Gravity
Loop quantum gravity is string theory’s biggest competitor. It gets less press than string theory, in part because it has a fundamentally more limited goal: a quantum theory of gravity. Loop quantum gravity [more…]
String Theory's Competition: What is Looping?
String theory's biggest competitor, loop quantum gravity's key insight is that you can describe space as a field;instead of a bunch of points, space is a bunch of lines. The [more…]
String Theory versus Loop Quantum Gravity
Loop quantum gravity makes some definite predictions, which may mean that it could be tested well before string theory can be. As string theory’s popularity is being brought into question, the amount of [more…]
Benefits and Flaws of Loop Quantum Gravity
As with string theory, loop quantum gravity is passionately embraced by some physicists and dismissed by others. The physicists who study it believe that the predictions [more…]
String Theory: Phantom Energy and Rogue Universes
In string theory, the assumption is that the separate, parallel universes don’t normally interact with each other, but some approaches over the years have called this into question. One of the most recent [more…]
String Theory: Parallel Universes and the Multiverse
In string theory, the multiverse is a theory in which our universe is not the only one; many universes exist parallel to each other. These distinct universes within the multiverse theory are called [more…]
String Theory: Level 1 Parallel Universes
In string theory, the idea of Level 1 parallel universes basically says that space is so big that the rules of probability imply that surely, somewhere else out there, are other planets exactly like Earth [more…]
String Theory: Plurality of Worlds in Early Astronomy
Before string theory was a theory, early astronomy provided some support for the existence of a plurality of worlds, a view that was so controversial that it contributed to at least one man’s death. These [more…]
String Theory: Level 2 Parallel Universes
In the string theory of a Level 2 parallel universe, regions of space are continuing to undergo an inflation phase. Because of the continuing inflationary phase in these universes, space between us and [more…]
String Theory: Chaotic Inflation and Eternal Inflation
The theories of eternal inflation and chaotic inflation in string theory can be quite confusing. Most people, even physicists, use them fairly interchangeably. This is an excellent example of how concepts [more…]
String Theory: Level 3 Parallel Universes
Of the four types of universes, Level 3 parallel universes have the least to do with string theory directly. A Level 3 parallel universe is a consequence of the many worlds interpretation [more…]
String Theory: Alternate History in Many Worlds Interpretation
Level 3 universes have the least to do with string theory, but of all the types of parallel universes, Level 3 universes have most captured the imagination of popular culture, spawning their own genre [more…]
String Theory: Level 4 Parallel Universes
In string theory, a Level 4 parallel universe is the strangest place (and most controversial prediction) of all, because it would follow fundamentally different mathematical laws of nature than our universe [more…]
String Theory: Accessing Other Universes
Is there any way to reach the four types of parallel universes in string theory? Realistically, the answer is probably “No,” but that’s not the most interesting option. Theoretically, there are ways that [more…]
String Theory: Travel between Parallel Universes with Wormholes
Even before string theory, the idea existed that the geometry of the universe would allow for shorter paths between points. In fiction, this can be seen in stories such as Lewis Carroll’s [more…]
String Theory: Access Parallel Universes with Quantum Tunneling
In string theory, one process of getting from one universe to another would be to use the property of quantum tunneling,which is where a particle is allowed to “jump” from one location to another across [more…]
How to Calculate Power Based on Work and Time
Sometimes, it isn’t just the amount of work you do but the rate at which you do work that’s important. In physics, the concept of power gives you an idea of how much work you can expect in a certain amount [more…]
Relating Impulse and Momentum through the Impulse-Momentum Theorem
In physics, you can connect the impulse you give to an object — like striking a pool ball with a cue — with the object’s change in momentum; all you need is a little algebra and a process called the [more…]
How to Calculate Force from Impulse and Momentum
In physics, you can use the impulse-momentum theorem to calculate force based on impulse and momentum. For example, you can relate the impulse with which you hit an object to its consequent change in momentum [more…]
How the Principle of Conservation of Momentum Works
In physics, the principle of conservation of momentumstates that when you have an isolated system with no external forces, the initial total momentum of objects before a collision equals the final total [more…]
How to Find the Velocity of Two Objects after Collision
You can use the principle of conservation of momentum to measure characteristics of motion such as velocity. Say, for example, that you’re out on a physics expedition and you happen to pass by a frozen [more…]
How to Determine Whether a Collision Is Elastic or Inelastic
In physics, collisions can be defined as either elastic or inelastic. When bodies collide in the real world, they sometimes squash and deform to some degree. The energy to perform the deformation comes [more…]
How to Calculate Velocities of Two Objects with Different Masses after an Elastic Collision
When a collision between two objects is elastic, kinetic energy is conserved. In physics, the most basic way to look at elastic collisions is to examine how the collisions work along a straight line. If [more…]
How to Change Equations from Linear Motion to Rotational Motion
In physics, when you go from linear motion to rotational motion, you need to change the equations that you use to calculate your results. Here are the angular equivalents [more…]
Calculating Tangential Velocity on a Curve
When an object moves in a circle, if you know the magnitude of the angular velocity, then you can use physics to calculate the tangential velocity of the object on the curve. [more…]
