Diseases, Conditions, Syndromes

Particulate matter from aircraft engines affects airways

In a unique, innovative experiment, researchers under the leadership of the University of Bern have investigated the effect of exhaust particles from aircraft turbine engines on human lung cells. The cells reacted most strongly ...

Neuroscience

Autism gene linked to brain and behavior deficits in mice

Mice lacking the gene Shank3 display structural and functional deficits in the prefrontal cortex, finds a study published in JNeurosci. The research advances our understanding of one of the most common genetic risk factors ...

Radiology & Imaging

Obesity linked with differences in form and structure of the brain

Researchers using sophisticated MRI technology have found that higher levels of body fat are associated with differences in the brain's form and structure, including smaller volumes of gray matter, according to a study published ...

Radiology & Imaging

High-strength MRI tracks multiple sclerosis progression

The development of scars, or lesions, in the brain's cortical gray matter is a powerful predictor of neurological disability for people with multiple sclerosis (MS), according to study appearing in the journal Radiology. ...

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Matter

Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume. However, different fields use the term in different and sometimes incompatible ways; there is no single agreed scientific meaning of the word "matter".

For much of the history of the natural sciences people have contemplated the exact nature of matter. The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, was first put forward by the Greek philosophers Leucippus (~490 BC) and Democritus (~470–380 BC). Over time an increasingly fine structure for matter was discovered: objects are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons.

Matter is commonly said to exist in four states (or phases): solid, liquid, gas and plasma. However, advances in experimental techniques have realized other phases, previously only theoretical constructs, such as Bose–Einstein condensates and fermionic condensates. A focus on an elementary-particle view of matter also leads to new phases of matter, such as the quark–gluon plasma.

In physics and chemistry, matter exhibits both wave-like and particle-like properties, the so-called wave–particle duality.

In the realm of cosmology, extensions of the term matter are invoked to include dark matter and dark energy, concepts introduced to explain some odd phenomena of the observable universe, such as the galactic rotation curve. These exotic forms of "matter" do not refer to matter as "building blocks", but rather to currently poorly understood forms of mass and energy.

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