You are looking at all articles with the topic "Physics". We found 185 matches.

Hint: To view all topics, click here. Too see the most popular topics, click here instead.

🔗 Spaceflight 🔗 Physics 🔗 Science Fiction

A black hole starship is a theoretical idea for enabling interstellar travel by propelling a starship by using a black hole as the energy source. The concept was first discussed in science fiction, notably in the book Imperial Earth by Arthur C. Clarke, and in the work of Charles Sheffield, in which energy extracted from a Kerr-Newman black hole is described as powering the rocket engines in the story "Killing Vector" (1978).

In a more detailed analysis, a proposal to create an artificial black hole and using a parabolic reflector to reflect its Hawking radiation was discussed in 2009 by Louis Crane and Shawn Westmoreland. Their conclusion was that it was on the edge of possibility, but that quantum gravity effects that are presently unknown will either make it easier, or make it impossible. Similar concepts were also sketched out by Bolonkin.

🔗 Physics 🔗 Electronics 🔗 Professional sound production

Pink noise or ​¹⁄_f noise is a signal or process with a frequency spectrum such that the power spectral density (energy or power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave (halving or doubling in frequency) carries an equal amount of noise energy.

Pink noise is one of the most common signals in biological systems.

The name arises from the pink appearance of visible light with this power spectrum. This is in contrast with white noise which has equal intensity per frequency interval.

🔗 Physics 🔗 Meteorology 🔗 Skepticism

A sun dog (or sundog) or mock sun, formally called a parhelion (plural parhelia) in meteorology, is an atmospheric optical phenomenon that consists of a bright spot to one or both sides of the Sun. Two sun dogs often flank the Sun within a 22° halo.

The sun dog is a member of the family of halos, caused by the refraction of sunlight by ice crystals in the atmosphere. Sun dogs typically appear as a pair of subtly colored patches of light, around 22° to the left and right of the Sun, and at the same altitude above the horizon as the Sun. They can be seen anywhere in the world during any season, but are not always obvious or bright. Sun dogs are best seen and most conspicuous when the Sun is near the horizon.

🔗 Biography 🔗 Mathematics 🔗 Religion 🔗 Physics 🔗 London 🔗 Philosophy 🔗 England 🔗 Biography/science and academia 🔗 Astronomy 🔗 Philosophy/Philosophy of science 🔗 History of Science 🔗 Philosophy/Philosophers 🔗 Biography/politics and government 🔗 Philosophy/Metaphysics 🔗 Physics/Biographies 🔗 Christianity 🔗 Christianity/theology 🔗 Lincolnshire 🔗 Anglicanism

Isaac Newton (4 January 1643 – 31 March 1727) was considered an insightful and erudite theologian by his Protestant contemporaries. He wrote many works that would now be classified as occult studies, and he wrote religious tracts that dealt with the literal interpretation of the Bible. He kept his heretical beliefs private.

Newton's conception of the physical world provided a model of the natural world that would reinforce stability and harmony in the civic world. Newton saw a monotheistic God as the masterful creator whose existence could not be denied in the face of the grandeur of all creation. Although born into an Anglican family, and a devout but unorthodox Christian, by his thirties Newton held a Christian faith that, had it been made public, would not have been considered orthodox by mainstream Christians. Scholars now consider him a Nontrinitarian Arian.

He may have been influenced by Socinian christology.

🔗 Physics 🔗 History of Science

The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century to early 20th century classical physics that an ideal black body at thermal equilibrium would emit an unbounded quantity of energy as wavelength decreased into the ultraviolet range.^: 6–7 The term "ultraviolet catastrophe" was first used in 1911 by Paul Ehrenfest, but the concept originated with the 1900 statistical derivation of the Rayleigh–Jeans law.

The phrase refers to the fact that the empirically derived Rayleigh–Jeans law, which accurately predicted experimental results at large wavelengths, failed to do so for short wavelengths. (See the image for further elaboration.) As the theory diverged from empirical observations when these frequencies reached the ultraviolet region of the electromagnetic spectrum, there was a problem. This problem was later found to be due to a property of quanta as proposed by Max Planck: There could be no fraction of a discrete energy package already carrying minimal energy.

Since the first use of this term, it has also been used for other predictions of a similar nature, as in quantum electrodynamics and such cases as ultraviolet divergence.

🔗 Physics

Barometric light is a name for the light that is emitted by a mercury-filled barometer tube when the tube is shaken. The discovery of this phenomenon in 1675 revealed the possibility of electric lighting.

🔗 Physics 🔗 Spectroscopy

Silicon drift detectors (SDDs) are X-ray radiation detectors used in x-ray spectrometry (XRF and EDS) and electron microscopy. Their chief characteristics compared with other X-ray detectors are:

• high count rates
• comparatively high energy resolution (e.g. 125 eV for Mn Kα wavelength)
• Peltier cooling

🔗 Mathematics 🔗 Physics 🔗 Lists 🔗 Anthroponymy

Carl Friedrich Gauss (1777–1855) is the eponym of all of the topics listed below. There are over 100 topics all named after this German mathematician and scientist, all in the fields of mathematics, physics, and astronomy. The English eponymous adjective Gaussian is pronounced GOWSS-ee-ən.

🔗 Physics 🔗 Physics/Glass

A glass knife is a knife with a blade made of glass, with a fracture line forming an extremely sharp cutting edge.

Glass knives were used in antiquity due to their natural sharpness and the ease with which they could be manufactured. In modern electron microscopy glass knives are used to make the ultrathin sections needed for imaging.

🔗 Physics 🔗 Astronomy 🔗 Physics/relativity 🔗 Astronomy/Astronomical objects

In general relativity, a white hole is a hypothetical region of spacetime and singularity that cannot be entered from the outside, although energy-matter, light and information can escape from it. In this sense, it is the reverse of a black hole, which can be entered only from the outside and from which energy-matter, light and information cannot escape. White holes appear in the theory of eternal black holes. In addition to a black hole region in the future, such a solution of the Einstein field equations has a white hole region in its past. This region does not exist for black holes that have formed through gravitational collapse, however, nor are there any observed physical processes through which a white hole could be formed.

Supermassive black holes (SBHs) are theoretically predicted to be at the center of every galaxy and that possibly, a galaxy cannot form without one. Stephen Hawking and others have proposed that these SBHs spawn a supermassive white hole/Big Bang.