Dark Matter.

[JMS_Legacy]

Definition: Dark energy is a hypothetical form of energy that permeates space and exerts a negative pressure, which would have gravitational effects to account for the differences between the theoretical and observational results of gravitational effects on visible matter. Dark energy is not directly observed, but rather inferred from observations of gravitational interactions between astronomical objects, along with dark matter.
The term "dark energy" was coined by the theoretical cosmologist Michael S. Turner.

Dark Energy's Predecessor

Before physicists knew about dark energy, a cosmological constant, was a feature of Einstein's original general relativity equations that caused the universe to be static. When it was realized the universe was expanding, the assumption was that the cosmological constant had a value of zero ... an assumption that remained dominant among physicists and cosmologists for many years.
Discovery of Dark Energy

In 1998, two different teams - the Supernova Cosmology Project and the High-z Supernova Search Team - both failed at their goal of measuring the deceleration of the universe's expansion. In fact, they measured not only a deceleration, but a totally unexpected acceleration. (Well, almost totally unexpected: Stephen Weinberg had made such a prediction once)
Further evidence since 1998 has continued to support this finding, that distant regions of the universe are actually speeding up with respect to each other. Instead of a steady expansion, or a slowing expansion, the expansion rate is getting faster, which means that Einstein's original cosmological constant prediction manifests in today's theories in the form of dark energy.

The latest findings indicate that over 70% of the universe is composed of dark energy. In fact, only about 4% is believed to be made up of ordinary, visible matter. Figuring out more details about the physical nature of dark energy is one of the major theoretical and observational goals of modern cosmologists.

Dark Energy - definition of dark energy

Here's an interesting question to ponder:
How long will Dark Energy be rapidly expanding the universe before it hits the point where it will re-condense all the galaxies back into one sphere?

Granted if that ever did happen, it would not be in our life time nor would we survive to know. Which can only make one wonder even more about it.

 

[Einstein]

Definition: Dark energy is a hypothetical form of energy that permeates space and exerts a negative pressure, which would have gravitational effects to account for the differences between the theoretical and observational results of gravitational effects on visible matter. Dark energy is not directly observed, but rather inferred from observations of gravitational interactions between astronomical objects, along with dark matter.
The term "dark energy" was coined by the theoretical cosmologist Michael S. Turner.

Dark Energy's Predecessor

Before physicists knew about dark energy, a cosmological constant, was a feature of Einstein's original general relativity equations that caused the universe to be static. When it was realized the universe was expanding, the assumption was that the cosmological constant had a value of zero ... an assumption that remained dominant among physicists and cosmologists for many years.
Discovery of Dark Energy

In 1998, two different teams - the Supernova Cosmology Project and the High-z Supernova Search Team - both failed at their goal of measuring the deceleration of the universe's expansion. In fact, they measured not only a deceleration, but a totally unexpected acceleration. (Well, almost totally unexpected: Stephen Weinberg had made such a prediction once)
Further evidence since 1998 has continued to support this finding, that distant regions of the universe are actually speeding up with respect to each other. Instead of a steady expansion, or a slowing expansion, the expansion rate is getting faster, which means that Einstein's original cosmological constant prediction manifests in today's theories in the form of dark energy.

The latest findings indicate that over 70% of the universe is composed of dark energy. In fact, only about 4% is believed to be made up of ordinary, visible matter. Figuring out more details about the physical nature of dark energy is one of the major theoretical and observational goals of modern cosmologists.

Dark Energy - definition of dark energy

Here's an interesting question to ponder:
How long will Dark Energy be rapidly expanding the universe before it hits the point where it will re-condense all the galaxies back into one sphere?

Granted if that ever did happen, it would not be in our life time nor would we survive to know. Which can only make one wonder even more about it.

I kind of look at the Dark Energy scenario as a complete cop out on the scientific communities part. The is no proof at all that Dark Energy exists. What does exist is a bunch of scientists willing to make something up instead of finding out about the real world that we live in.

 

[JMS_Legacy]

Hahah, Very true there are a lot of scientists that fit that description.
Evidence does support that the universe is expanding though, even if it isn't by Dark Energy.

 

[TnWatchdog]

I am not an expert on any of this but I find it to be an interesting topic, "Dark Energy"...Plays in with discussions on Black Holes and the Galactic Alignment, which will happen on 12-21-12. This aligment has happened back in the early Mayan days and scientists aren't sure what could or would happen as they weren't around on the first go around. Someone recently on C2C said the sun could act as a lens for whatever is in the center of the Galaxy...Dark Matter or whatever and magnify this towards us. Interesting topics, which I am just starting to study. I watched a series done by Stephen Hawkin that showed how the planets revolving around the sun were moving with the sun to kingdom come...and keep on expanding...out towards outer space.

 

[TnWatchdog]