Science | Definition, Disciplines, & Facts | Britannica
2025年1月9日 · Science, any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation. In general, a science involves a pursuit of knowledge covering general truths or the operations of fundamental laws.
Science Portal | Britannica
2025年1月10日 · What’s the matter? Matter is the material substance that constitutes our whole observable universe, and it is the subject of study of physics. Physics, the basic physical science, studies objects ranging from the very small (using quantum mechanics) to the entire universe (using general relativity).
Star | Definition, Light, Names, & Facts | Britannica
2025年1月11日 · Of the tens of billions of trillions of stars in the observable universe, only a very small percentage are visible to the naked eye. Why do stars twinkle? As the light emitted from a star passes through the different layers of Earth’s atmosphere, turbulence causes the …
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
2025年1月7日 · galaxy, any of the systems of stars and interstellar matter that make up the universe. Many such assemblages are so enormous that they contain hundreds of billions of stars.
Dark energy | Definition, Discoverers, & Facts | Britannica
2025年1月9日 · dark energy, repulsive force that is the dominant component (69.4 percent) of the universe. The remaining portion of the universe consists of ordinary matter and dark matter. Dark energy, in contrast to both forms of matter, is relatively uniform in time and space and is gravitationally repulsive, not attractive, within the volume it occupies.
Earth | Definition, Size, Composition, Temperature, Mass, & Facts ...
2025年1月10日 · Earth, third planet from the Sun and the fifth largest planet in the solar system in terms of size and mass. Its single most outstanding feature is that its near-surface environments are the only places in the universe known to harbor life. Learn more about development and composition of Earth in this article.
Matter | Definition, Characteristics, States, Examples, & Facts ...
2025年1月8日 · Matter, material substance that constitutes the observable universe and, together with energy, forms the basis of all objective phenomena. At the most fundamental level, matter is composed of elementary particles known as quarks and leptons (the class of elementary particles that includes electrons).
Life - Origin, Evolution, Abiogenesis | Britannica
2025年1月10日 · The origin of life is a result of a supernatural event—that is, one irretrievably beyond the descriptive powers of physics, chemistry, and other science. Life, particularly simple forms, spontaneously and readily arises from nonliving matter in …
Biography, Philosophy, Logos, Fire, & Facts - Britannica
2025年1月7日 · Heraclitus, Greek philosopher remembered for his cosmology, in which fire forms the basic material principle of an orderly universe. Little is known about his life, and the one book he apparently wrote is lost.
Anthropic principle | Cosmology, Physics & Philosophy | Britannica
2025年1月9日 · The anthropic principle implies that life could not exist in a universe that was significantly smaller than the observed universe. relative size of the universe How the relative size of the universe changes with time in four different models.