Fjords may emit as much methane as all the deep oceans globally

During heavy storms, the normally stratified layers of water in ocean fjords get mixed, which leads to oxygenation of the fjord floor. But these storm events also result in a spike in methane emissions from fjords to the ...

Hubble looks at a face-on grand spiral

This image from NASA's Hubble Space Telescope features the Grand Design Spiral, NGC 3631, located some 53 million light-years away in the direction of the constellation Ursa Major. The "arms" of grand design spirals appear ...

Digging into soil biology recovery after petroleum contamination

Spills and leaks of petroleum products wreak havoc on the environment. They can contaminate soils and pose significant threats to humans, animals, plants, and soil microbes. Cleaning up petroleum contamination can be energy ...

Ghostly 'mirror world' might be cause of cosmic controversy

New research suggests an unseen "mirror world" of particles that interacts with our world only via gravity that might be the key to solving a major puzzle in cosmology today—the Hubble constant problem.

Developing a better diagnostic nano-probe

Biomarkers are components that may be present in biological samples and are related to specific diseases. Therefore, doctors can analyze biological samples from a patient to check their health condition or to monitor the ...

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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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