File Name: what is dark matter and dark energy .zip
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- The Invisible Universe: Dark Matter and Dark Energy
- Dark Matter and Dark Energy in General Relativity and Modified Theories of Gravity
It seems that you're in Germany. We have a dedicated site for Germany. Editors: Matarrese , S. This book brings together reviews from leading international authorities on the developments in the study of dark matter and dark energy, as seen from both their cosmological and particle physics side. Studying the physical and astrophysical properties of the dark components of our Universe is a crucial step towards the ultimate goal of unveiling their nature. The work developed from a doctoral school sponsored by the Italian Society of General Relativity and Gravitation. The book starts with a concise introduction to the standard cosmological model, as well as with a presentation of the theory of linear perturbations around a homogeneous and isotropic background.
The Invisible Universe: Dark Matter and Dark Energy
Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. What is the universe made of? The answer to this very simple question is not so simple. Baryons, the familiar neutrons and protons of which we, Earth, and the stars are made of, do not account for most of the mass in the universe.
Expressed a fraction of the critical density it goes like this: neutrinos, between % and 15%; stars, %; baryons. (total), 5%; matter (total), 40%; smooth, dark.
Dark Matter and Dark Energy in General Relativity and Modified Theories of Gravity
Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. For this reason, most experts think that dark matter is abundant in the universe and that it has had a strong influence on its structure and evolution. Dark matter is called dark because it does not appear to interact with the electromagnetic field , which means it does not absorb, reflect or emit electromagnetic radiation , and is therefore difficult to detect.
Unlocking the Mystery
The visible universe — including Earth, the sun, other stars , and galaxies — is made of protons, neutrons, and electrons bundled together into atoms. Perhaps one of the most surprising discoveries of the 20th century was that this ordinary, or baryonic, matter makes up less than 5 percent of the mass of the universe. The rest of the universe appears to be made of a mysterious, invisible substance called dark matter 25 percent and a force that repels gravity known as dark energy 70 percent. Scientists have not yet observed dark matter directly. It doesn't interact with baryonic matter and it's completely invisible to light and other forms of electromagnetic radiation, making dark matter impossible to detect with current instruments.
In physical cosmology and astronomy , dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovae, which showed that the universe does not expand at a constant rate; rather, the expansion of the universe is accelerating. Prior to these observations, the only forms of matter-energy known to exist were ordinary matter , antimatter , dark matter , and radiation. Measurements of the cosmic microwave background suggest the universe began in a hot Big Bang , from which general relativity explains its evolution and the subsequent large-scale motion. Without introducing a new form of energy, there was no way to explain how an accelerating universe could be measured.
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