Frequently Asked Questions about Modern Physics

What are Black Holes?

A black hole, which is actually a black sphere, is a term used to describe an area in the space-time continuum that has a gravitational field so strong that even light itself can not escape. Black holes are formed after stars of a certain mass, say 20 times the mass of our sun, have exhausted their nuclear fuel. Stars are a balance of the nuclear force , a force that tends to blow things apart, and the gravitational force, a force that tends to pull on objects. Once a star has exhausted its nuclear fuel, a delicate balance is broken and the gravitational force becomes dominant. The dominant force of gravity continues to work on the nuclearly exhausted star. Gravity forces the star to decrease in radius, but this decrease in radius does not effect the mass. The star keeps its mass, but it is squeezed into a much smaller portion of space-time by the force of gravity. As this decrease in radius continues, the star becomes a black hole.

Because of the fact that most light or electromagnetic radiation can not escape to be detected by our instruments, the black hole is perceived by us, humans, as "black". Since the scientific community has found that theoretically nothing can travel faster then the speed of light, no object can escape the gravitational field once it has passed the "Event Horizon".

The event horizon is simply one of the mathematical tools used by theoretical physicists to show the distance in which an object can come without being pulled into the black hole. Once an object has crossed the event horizon, it is inevitable that the history of the object will cease to exist in real time. The object will then be pulled closer and closer until reaches the singularity of the black hole. This is a point supposedly located at the center of the black hole. At this point in the black hole, the curvature of space time approaches and/or reaches that of infinity. To put it another way, the forces at the center of a black hole, caused by the singularity, are infinite. Theoretically, almost all laws of physics break down in a singularity. After one has crossed over into the complex world of singularities, quantum mechanics must be used.

If an object, say an astronaut, crosses the event horizon, it is inevitable that the astronaut encounter the singularity hiding at the center of the black hole. If there is an observer on the outside of the black hole watching the astronaut fall in, that observer will have experiences. The astronaut that falls into the black hole will experience a finite time interval between his crossing the event horizon and encountering the singularity, but the observer on the out side of the black hole will experience an infinite amount of time between seeing the astronaut cross the event horizon and fade away into depths of the black hole. Billions upon billions of years may have passed for the observer on the outside of the black hole, because to the observer on the outside of the black hole, it seems as though the astronaut with the poor luck of being captured by the black hole is simply trapped a one point in space and in time.

What are Worm Holes?

Worm holes are possible gateways that connect different points in space-time. To be more accurate, worm holes can connect two different points in space, time, or space time. When a worm hole connects two different points in space, an object can move from one point in space to another point in space. When a worm hole connects two different points in time, an object can move from one point in time to another. In a sense, this worm hole is actually a time machine. When a worm hole connects two different points in space time, it can transport an object from one point in space-time to another. By using a worm hole, one can take advantage of multiply connected space-times and travel longer distances in shorter periods of time or make use of the time aspect of the worm hole.

Some theoretical physicists believe that if we find a way to move an object(probe, spaceship, ete) faster then the speed of light, we can shoot an object into a black hole. Because the object is moving faster then light, it will be able to penetrate the singularity, a place of infinite curvature in space time, and move into a parallel universe. This worm hole moves would move an object from one possible universe to another.

This aspect of space-time could be one of great importance in the future. The required energy to rip a hole in the space-time continuum and connect it with another rip is much greater than any energy the human race can harness. If this energy is ever gained, wormholes could be a very important factor in long distance space travel. Along with finding energy, we would have to find what is now called "exotic matter". This exotic matter would help stabilize the gravitational forces acting on the worm hole. Because gravitational forces tend pull objects, the purpose of the exotic matter would be to " push or blow". The slightest disturbance, in an unstable worm hole would cause it to close possibly forever.

What is Anti-Matter?

Anti-matter is a type of matter that has a different electrical charge compared to its matter counterparts. When anti-matter comes in contact with matter, the two annihilate each other and unleash numerous subatomic particles radiation that travel out at the speed of light. By combining Anti-matter and matter, one will produce pure energy. This could be the most efficient way of obtaining energy required for the society of the future.

What is Dark Matter?

Dark matter is matter that can not be detected by our instruments. The configuration of the particles and subatomic particles stops all electromagnetic radiation. This means that the matter does absorb or emit any type of electromagnetic radiation. Its atomic configuration shields it from radiation.

Some theoretical physicists believe that dark matter may be made up ofmaterials completely different form that of "normal" matter. That means that the dark matter may be made up of something completely different from protons, neutrons, and electrons.

Scientists have calculated that 90 to 99 percent of the observable universe is composed of dark matter and have found that dark matter does exist by studying the motion of hydrogen gas clouds, of stars, and of the large and small Magellanic Clouds around the galactic center, and using Newton's laws relating the velocity of orbiting objects to the mass pulling them.

Will a person at the top of a building age at a different rate due to gravitational field?

Yes, a person at the top of a building will age at a faster rate, because they are located in a weaker gravitational field. One can understand this idea by thinking of concepts related to Einstein's General Theory of Relativity. According to Einstein, the slowing of time varies directly with the strength gravatational field.

What are Nanobots?

Nanobots are robots with dimensions measured in the billionth,10^9. One might ask, "What difference could small robots make in our society?" To put it in mild terms, when and if the technology, commonly referred to as nanotechnology, is perfected, the presence of nanobots in our society would revolutionize the way we live. Researchers have been working fast and furious on developing and perfecting the technology needed to bring about this "miniature" revolution.

A robot arm is being designed by Ralph Merkle and Eric Drexler. This arm contains approximately four million atoms. When one first hears this, words such as magnificent, amazing, and incredible do not come to mind because this sounds like a tremendous amount, but in actuality, this robot arm is the size of a dust mote! If you placed these robot arms on a baking tray, you could fit more than 62 billion per square inch on the baking tray.

The idea that makes this concept so powerful is that instead of making molds, stamping out components, smelting steel, and fitting parts together on an assembly line, we could construct materials molecule by molecule. This could be a time consuming process. This problem could be averted by interfacing with the internal computer system, a computer system that would allow for an incredible variety of different commands, of the robot arm. The most logical thing to do with this single robot arm would be to create another robot arm. This process could occur until the number of robot arm or nanobots was at the required amount. Obviously, as the number of nanobots increases, the amount of work done in a certain period of time increases. To put it in simpler terms, the nanobots are more powerful.

The uses of these nanobots are limitless. Nanobots could create whole new cities, disassemble old cities, disassemble pollution of all types, create new and remarkable drugs, make televisions, homes, repair roads and highways, or destroy cancer cells. These are just a few examples of possibilities that could occur using nanotechnology.

Why doesn't fusion occur naturally on earth?

Outside of stars, fusion does not occur naturally on earth due to the nature of its reaction. In order for nuclei to be fused, they have to be close together. Also nuclei are positively charged and will electrically repel one another. To fuse, they must collide with enough energy to overcome the repulsion due to their electric force.

What is Hawking radiation?

In 1975, Hawking published a paper that said that black holes aren't black, but glow slightly with what he dubbed Hawking radiation, which consists of photons, neutrinos, and even massive quarks. He predicted that it should glow like a blackbody (which is the ideal absorbtion medium). However, this glow would only be significant for small black holes.

What does Length Contraction have to do with the Special Theory of Relativity?

When dealing with the Special Theory of Relativity, the concept of length contraction is very important. As objects move through the space relativistic speeds, the dimension of this particular object that is in the direction of motion will began to contract. The extent of this dimensional contraction depends entirely upon the relativistic speeds of the object. The dimension that is perpendicular to the direction of motion is not affected by the relativistic speeds of the object, and because of this, this dimension does not contract. FitzGerald and Hendrick A. Lorentz developed the idea and the mathematical expression of length contraction. The expression

L=Lo(((1-((v/c)^(2)))^(1/2))

shows all the different factors that go into account when looking at the length of an object moving at relativistic speeds.In this expression, (L) is the length of the object in motion, (Lo) is the length of the object while at rest, (v) is the speed of the object, and (c) is the speed of light in a vacuum.

What does Mass Increase have to do with the Special Theory of Relativity?

Mass increase is fundamental concept in the Special Theory of Relativity. When objects travel at relativistic speeds, they increase in mass. When a force interacts with an object, the object under goes acceleration, which is a change in velocity. By looking at Newton's second law of physics, one can see that (a = F/m). In this equation, (F) is average force, (m) is the mass of the object, and (a) is the acceleration. From the formula (a = F/m), it can be seen that acceleration varies directly with the applied force. This also means that the acceleration varies inversely with the mass of the object. As the force imparted on an object increase, the acceleration increases, but as the mass of the object increases, the acceleration decreases. As the acceleration of the object increases, its velocity. As long as the acceleration increases, the velocity will increase to a point. Due to present technology and because of the lack of energy/matter, this point is the speed of light. In theory, nothing can travel faster than the speed of light, 3.0 * 10^8 m/s. As an object travels faster and faster, it gains mass but, where does this mass come from? This mass comes from the energy of the object. As the object travels faster and faster, it acquires more and more energy. This energy shows up in the form of an increased mass. The fact that energy and matter are the same thing allows for this concept to be true. The relationship between relativistic mass and rest mass is shown in the equation

m = (mo/((1-((v/c)^2))^(1/2))).

In this equation, (m) is the relativistic mass, (mo) is the rest mass, (v) is the relativistic velocity, and ( c) is the speed of light. This formula allows one to find the relativistic mass of an object traveling at relativistic speeds.

What is Time Dilation when talking about the Special Theory of Relativity ?

When objects move at non-relativistic speeds, space and time are more constant and the speed of the object is relative, but when this object moves at relativistic speeds, space and time are relative ,where as; its speed is constant. This shows that time is not an absolute value for the universe because it depends on your position and type of motion in the universe. This speed reaches a limit at 3.0*10^8 m/s, which is the speed of light. Objects that move at relativistic speeds under go time dilation. This is one of the most important characteristics of objects that move at relativistic speeds. The faster an object moves, the slower its time is relative to an outside observer. This fact becomes very powerful when an object moves at relativistic speeds. The formula

t = (to)/((1-((v^2)/(c^2)))^(1/2))

allows one to find the relativistic time. In this formula, (t) is the relativistic time,(to) is the non-relativistic time, (v) is the speed of the object, and (c) is the speed of light.