What is

Dark Energy?

 

Dark Energy is apparently an infinitesimally small particle that uniformly spreads over the universe, compromising the vast majority of matter. It can be referred to in terms of the cosmological constant: the name given to a term in Einstein's equations of general relativity. If it is not zero, then it represents a repulsive force or a type of energy (sometimes called dark energy or quintessence) that might cause the expansion of the universe to accelerate with time.

 

quick facts

• Roughly 70% of the universe is dark energy

• Dark energy is pulling galaxies apart

• Dark energy is a property of space

Composition of the Universe:

 

 

According to NASA Science, more is unknown than is known about Dark Energy. Astronomers know how much dark energy there is because they know how it affects the Universe's expansion. Other than that, what Dark Energy really is, is a complete mystery. How can space aquire energy? Eventually theorists came up with 3 explanations.

 

albert

THE FIRST EXPLANATION:

Albert Einstein was the first person to realize that empty space is not nothing, and that is how we know that more dark energy is continuously being created. The first property that Einstein discovered is that it is possible for more space to come into existence. Now, there is a second prediction to this discovery and that is that empty space can have its own energy. Because energy is a property of space and the universe, it wouldn't be diluted as the space expands.

 

A SECOND EXPLANATION:

The second explanation for how space can acquire energy came from the Quantum Theory of Matter. This theory states that empty space is filled with temporary particles that continually form and then disappear. However, when it came time for astronomers to calculate the amount of energy this would give empty space, the answer came out incredibly wrong and by a tremendous amount. The answer came out 1 X 10 to the 120 power TOO BIG! This ruled out this explanation and the mystery continues.

A THIRD EXPLANATION:

A third explanation for dark energy is that it could be a new energy fluid or field that can fill space but has an opposite effect on the expansion of the universe compared to matter and normal energy. According to NASA Science, some theorists have named this "quintessence," after the fifth element of the Greek philosophers. But, if quintessence is the answer, we still don't know what it is like, what it interacts with, or why it exists.

 

 

more on dark energy:
  
  • According to the cosmic microwave background, 30% of the density is left to matter and baryons. This leaves roughly 70% of the universe's composition as dark energy.
  • Dark energy was a term coined by Michael Turner in 1998 as an explanation to an additional unknown component in the universe.
  • According to recent research by the Hubble Space Telescope's Higher-Z Team, dark energy's existence predates the estimated start of cosmic acceleration.
  • Dark energy is thought to have existed for 9 billion years.
  • Dark energy's concept was initially thought of as a sort of balance to gravity
  • Standard Candles is the primary measurement of gauging light over long distances, and as a result it makes for a great method of finding black holes.
  • The luminous matter from a supernova tends to be much less than the total mass ought to be, suggesting the presence of something more... like dark energy.

Cosmic Microwave Background

Michael Turner

 

 

What astronomers need to finalize an explanation on the possibilities of dark energy is simply to acquire more data. The Joint Dark Energy Mission (JDEM) is a NASA mission attempting to obtain this data and is being developed jointly by NASA and the Department of Energy. Its goal will be to provide observations of the Universe that will allow theorists to distinguish between theories, and perhaps, finally lead to the solution of the mystery.

 

SNAP, the SuperNova/Acceleration Probe, is one of three concepts competing for NASA and DOE's Joint Dark Energy Mission (JDEM). (Credit: Image courtesy of Lawrence Berkeley National Laboratory)

Learn More about JDEM: Science Daily

 

 

Watch this video to learn more about dark energy!

 

 

All this information about Dark Energy helps us answer a question that has been heavily discussed by astronomers:

Is the Expansion of the Universe Accelerating?

CLICK ABOVE TO FIND OUT!

 

 

also, some articles that may be of interest to you...

Dark, Perhaps Forever

http://www.nytimes.com/2008/06/03/science/03dark.html

What are dark matter and dark energy, and how are they affecting the Universe?

http://www.sciam.com/article.cfm?id=what-are-dark-matter-and

What is the Mysterious Dark Energy Pulling the Universe Apart?

http://universe.nasa.gov/science/darkenergy.html

Dark Energy--the Mystery that Dominates the Universe

http://purl.access.gpo.gov/GPO/LPS95710