Dark Energy

In the early 1990's, scientists had pretty much agreed that the rate that the universe was expanding had to be slowing down. It was assumed that, over time, gravity would begin to slow the expansion of the Universe. However, in 1998 information provided by the Hubble Space Telescope contradicted the theory based on logic. The Hubble's Photos proved that the universe had not been slowing down. On the contrary, it has been speeding up! Science proved again to be unpredictable. Theorists still have no accepted theory to explain how the universe is expanding, the only thing they do know is that they are calling this solution dark energy.

The only thing we know for sure is how much dark energy is in the known universe. We know how much there is because we understand the way dark energy affects the universe's expansion. Astonishingly, dark energy makes up 70% of the universe; there is more dark energy than there is anything else in the universe. In a distant second, dark matter accounts for 25% of the universe.

Other than that, it is a complete mystery. But it is an important mystery. It turns out that roughly 70% of the Universe is dark energy. Dark matter is a distant second, making up about 25% of the Universe. Now if you have been paying attention you might have realized that matter, as we know it, (rocks, buildings, planets, stars, galaxies, everything that we can see,) adds up to less than 5% of the universe. All of this being considered, would not dark matter be the standard in the universe because there is only a fraction the amount of matter.

So far the best answer for todays question has come from, who else? Albert Einstein. In one version of Einstein's gravity theory he includes a “cosmic constant.” Einstein described this constant as a counter balance for gravity. (After all, everything in the universe is supposed to balance out, hypothetically). Einstein's “cosmic constant” and today's “dark energy” are the same thing. In this version of Einstein's gravitational theory, dark energy pushes against matter's gravity causing all matter to move further apart from one another at an increasing rate because of the “cosmic constant.”

Multiverse Theory

As we have discusses in previous posts, there are stars with enough mass to collapse on themselves, forming black holes. It is thought that within these black holes there is a point called "singularity" at which all physical laws may stop to exist. Space-Time becomes infinitely large. Once all physical laws ceases to exist and would be given a chance to start anew or if even that much at all. Whatever it was would have an infinite number of possibilities. Physics has been thrown out and the slate wiped clean. Multiverse Theory supports the idea that every time a black hole is formed a new universe is born with it. If this was in-fact true it would mean that our universe could create as many new universes as it contained galaxies, for at the heart of every galaxy is a black hole. If every universe could produce an infinite number of universes who's to say that everything that could possibly happen, wouldn't happen? With an infinite number of tries you've already got better odds than you are going to find in vegas.

With each of these black holes there is a new point of singularity and a new possible universe. As Rees describes it, "Our universe may be just one element - one atom, as it were - in an infinite ensemble: a cosmic archipelago. Each universe starts with its own big bang, acquires a distinctive imprint (and its individual physical laws) as it cools, and traces out its own cosmic cycle. The big bang that triggered our entire universe is, in this grander perspective, an infinitesimal part of an elaborate structure that extends far beyond the range of any telescopes." (Rees 3) This makes our mark, as human beings, in the Multiverse even smaller. One galaxy in a universe turned into one galaxy in an infinite number of universes are two different things. After taking this into consideration perhaps life is a much scarcer occurrence than we already give it credit for. If this hypothesis were true how often would a universe that developed life be? It would be a shift in thinking that may help explain our big bang theory and possibly give light to the idea of parallel universes.

Sources

Rees, Martin. Before the Beginning. Reading, MA: Helix Books, 1997.

Can Anything Travel Faster Than Light

Einstein hypothesized, in 1906, that it was impossible for anything to move faster than the speed of light. In the last year, however, this postulation has been put to the test. Last year, Antonio Ereditato, coordinator of the OPERA experiment at The Nation Institute Of Nuclear Physics (INFN), challenged this theorization.

Einstein hypothesized that the speed of light (in a vacuum) was approximately 186,280 miles per second or 700 million miles per hour. He theorized that this was the max speed anything could reach and implemented it in his theory of relativity.

Physicists running routine neutrino experiments between CERN’s Geneva HQ in Switzerland and the Gran Sasso laboratory in Italy 455 miles away have found that their neutrinos seem to be traveling faster than the speed of light. That’s right: faster than the fastest known speed in the universe.

If these findings are factual this would be a historical discovery of immense proportions. The CERN physicists were firing neutrinos (which do not interact with normal matter and can pass directly through the earth) at the INFN.

Time, however, is a function of relative motion. The faster you move relative to another object, the slower your time moves relative to the time at that object. As you approach the speed of light, this effect intensifies, making it harder and harder to go faster and faster. Remember: to move you must push on something. Your car pushes off the road to move forward (or to move the road back), a rocket thrusts exhaust back to move forward. The energy needed to accelerate increases as your speed approaches the speed of light. And, as my dad used to say, "There's always one more [factor] than you counted on." As you approach the speed of light, your mass increases. The more mass you are trying to move, the more energy you need to move it. At the speed of light, your mass theoretically becomes infinite, requiring infinite energy to move it any faster.

Unfortunately for the physicists, their results were wrong. They were due to an inaccurate distance between the two labs. Nothing travels faster than the speed of light. In physics-as-we-understand-them, it is the absolute and ultimate speed limit in our universe. We’ve tested and retested the speed of light, measured it in as many ways as we can think of, and much of modern physics is built upon the idea that nothing can exceed it.

How Fast Is Light

186,282 miles per second, Light moves at 671 million miles per hour, 16.1 billion miles per day and 5.89 trillion miles per year; That is exactly how fast light is. Light is the fastest thing in the universe and because of that we use it's max speed over one year as a benchmark for very long distances. Everyones perspective of “light speed” is basically the same, as fast as possible, but how fast is “light speed”, really? Some examples may surprise you:

• Light from the Sun takes 8 minutes and 17 seconds to reach us, but inside the sun the energy takes millions of years to go from the center to the surface.

• It takes about 1.3 seconds for light or radio waves to reach us from the Moon, which really isn't all that far away (it's only 20 times farther away than Australia is to the United States). During the Apollo mission NASA had to wait about three seconds to hear the answer to every question they asked the astronauts. When the ship was on the opposite side of the moon that time would nearly double because the satellites available to send messages off of were at their greatest distances. The message had to be sent roughly twice the distance back to NASA.

• When Mars is closest to the Earth, it takes light three minutes to travel between the two planets. If you asked a question to an astronaut on Mars, you'd have to wait at least six minutes for an answer, and Mars is usually a lot farther away than that. At its greatest distance, you'd have to wait 42 minutes.

• Light takes four and a half years to travel to the nearest star (excluding the sun).It also takes light 100,000 years to travel across the width of our Milky Way Galaxy and 100 billion years to travel across the observable Universe, as it stands today.
  
  
  
  

When you think about the speed of light compared to the size of the known universe it becomes extremely less impressive. What stands out is how large the known universe is. Trying to comprehend how large that is almost gives you a headache. If the speed of light is the maximum speed that anything can travel at it would be impossible to explore the entire universe because it is always expanding.

What Is Light

Light, simply put, is energy. It is how energy moves through space. Not so simply put, light is electromagnetic radiation. Visible light, that we are used to referring to, is only a sliver of the electromagnetic spectrum. The portion of the spectrum that we can see is approximately at the center. Below visible light in the spectrum lies infrared, micro and radio waves which have shorter frequencies. Above visible light is ultraviolet light, “x” rays and gamma rays which have higher frequencies.  Light bends the rules of physics by having properties of both a particle and a wave. 

Light can be described as a particle because it can be represented by a photon, or quantized amount of light energy. How much energy it contains determines where in the electromagnetic spectrum it resides. However, Light has other properties that allow it to be categorized as a wave also.

It is more difficult to think about light in this way but comparing it to sound waves helps.

When two different notes are played on a piano at the same time, the only difference between the sounds are the frequencies that the vibrating strings are producing. The higher the note, the higher the frequency and the shorter the wave lengths. When observed in this context light works virtually the same way. The higher the energy (frequency) inside the photon the highers that photon belongs on the light spectrum. Different levels of energy, inside a photon, produce different colors. If this description isn't helpful for you perhaps this example will: if you turn the light on in the hallway and a bedroom door is slightly ajar how does the light enter the room? The light spreads out. Even though the door is only open an inch or two you can see much more than you would think. If light did not act like a wave then you would only be able to see an area of equal proportions to the ajar door. This is known as diffraction. This phenomenon is what makes light an “X” factor in the universe.

Black Holes

One of the greatest mysteries of space is blackholes.  A black hole is a place in space that has a huge gravitational pull.  The pull is so great that not even light can get away.  A dying star can produce a black hole depending on the mass of the star.

Because light can not escape a black hole they are invisible.  The only way they can be detected is special instraments that observe stars abnormal tendencies.

Black holes can range in size.  Scientists hypothesis that the smallest black hole can be as large as an atom.  A black hole this small, however, would have the same mass as a mountain.  Mass is a measurement of how much matter an object contains.

The next category is a "stellar" black hole.  The mass of a stellar black hole can range up the mass of 20 of our own sun.  These move around the universe and pull in anything that gets too close to them.  

The largest black holes are called "supermassive" black holes.  These have the mass exceeding 1 million of our suns together.  Astronomers have confirmed that there is a supermassive black hole at the center of every galaxy.  These black holes keep the galaxys from flying off in all directions.  In the center of our galaxy, the black hole's mass is equal to approximately 5 million suns. 

The Big Bang

If the Big Bang theory is correct, at the instant that it occurred it was and is still the largest explosion in the history of the universe.  By using the speed that objects are moving and how quickly they are moving away from each other, scientist have hypothesized that the universe is 15 billion years old. In the first few seconds after it occurred, there was so much going on, in such a small amount of time that scientists from broke it down into "plank seconds."  Theoretically, this is the smallest time measurement that will ever be possible.  In every second, there are 10 ^43 plank seconds.  There are more plank seconds in one second than there have been seconds, since the Big Bang.  After about one to three minutes had passed since the creation of the universe, protons and neutrons began to react with each other to form deuterium, an isotope of hydrogen.  Deuterium, or heavy hydrogen collected together to form tritium.  These were the first two elements that were formed.  In the next three minutes helium was formed and over the next fifteen billioin years, here we are today.  

Looking deep into the universe is essentially the same thing as looking into the past.  A huge question that percists is weather the universe is finite.  Is there a definate end to it?  This will be the next blog topic.