Dark Matter and Dark Energy

Dark matter is a type of matter hypothesized in astronomy and cosmology to account for a large part of the mass that appears to be missing from the universe. Dark matter cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation at any significant level. Instead, the existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe. According to the Planck mission team, and based on the standard model of cosmology, the total mass--energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe and 26.8% of the total content of the universe. (from

The Universe: Dark Matter and Dark Energy
This looks at the theory of dark matter which accounts for 21% of the total mass-energy of the universe, and dark energy which accounts for 75% of the total mass-energy of the universe.

Stephen Hawking's Universe: On the Dark Side
What is the destiny of the universe? This episode features the scientists who are searching for dark matter consisting of more than 99% of the mass of the universe.

Dark Matter: Most of Our Universe Is Missing
According to the best estimates, we only know what about 4% of the universe is made of. The rest is made of mysterious entities about which very little is understood, with equally mysterious names: dark matter and dark energy.

Is Everything We Know About the Universe Wrong?
This documentary explores the theories in the field of cosmology related to our current understanding of the birth and evolution of the universe, from the Big Bang theory to dark energy theory and 'Dark Flow' found by Sasha Kashlinsky.

The Mystery of Dark Energy
The effects of dark energy were discovered in 1998 but physicists still don't know what it is. Worse, its very existence calls into question Albert Einstein's general theory of relativity - the cornerstone of modern physics.

Dark Energy: Dark Matter: Dark Gravity
Dark energy and dark matter pervade the Universe. Professor Alan Heavens looks at how we find their properties and tests whether Einstein's gravity theory works.

Dark Energy, or Worse: Was Einstein Wrong?
This talk explores the history of dark energy and dark matter by following Einstein's path to uncovering the theory that sparked a change in the world of astrophysics and the controversies behind that theory.

Related Links
Dark Matter - wikipedia
Dark matter is a type of matter hypothesized in astronomy and cosmology to account for a large part of the mass that appears to be missing from the universe.
Dark Matter, Dark Energy: The Dark Side of the Universe
This introduces modern cosmology through a focus on dark matter and dark energy, exploring scientific theories and observations such as Einstein's theory of general relativity and Edwin Hubble's discovery.
The Search for Dark Matter
The search for a better understanding of dark matter is carried out both out in space and deep underground, and where astrophysics meets particle physics.
Dark Matter Universe on the Threshold of Discovery
Ninety-five percent of the universe is missing! Astronomical observations suggest that most of the mass of the universe is in a mysterious form known as dark matter ...
Dark Energy Rules the Universe
The revolutionary discovery that the expansion of the universe is speeding up, not slowing down from gravity, means that 75 percent of our universe consists of mysterious dark energy.
Dark Energy and the Runaway Universe
Observations of very distant exploding stars show that the expansion of the Universe is now speeding up, rather than slowing down due to gravity as expected.
The Invisible Universe
We believe that 96% of the mass and energy content of our Universe is invisible. Some is in the form of Dark Matter whose presence we can only detect by its gravitational influence. The majority, called Dark Energy, appears to be ripping our Universe apart.