Psychology & Psychiatry

Human behaviour follows probabilistic inference patterns

How do human beings perceive their environment and make their decisions? To successfully interact with the immediate environment, for human beings it is not enough to have basic evidence of the world around them. This information ...

Ophthalmology

Flying hospital helps blind patients see

Most people who board this blue-and-white MD-10 cargo plane will never leave the ground—instead, they'll take a different type of journey.

Diseases, Conditions, Syndromes

Deplaning in Va. delayed while Ebola scare checked

Passengers disembarking from a commercial flight in Richmond, Virginia, on Friday were delayed by about an hour while authorities ruled out Ebola as a cause of a fellow passenger's symptoms.

Health

Unusual pattern of spine injuries from jet crash

Many survivors of Saturday's jet crash in San Francisco have a surprising pattern of spine injuries that a doctor says shows how violently they were shaken despite wearing seat belts.

Diseases, Conditions, Syndromes

Measles contagious on planes, study reports

Measles can be spread on planes in rows far beyond infected passengers, a Australian study showed Wednesday, raising questions over control guidelines for the disease.

Psychology & Psychiatry

Getting your message across

Far from processing every word we read or hear, our brains often do not even notice key words that can change the whole meaning of a sentence, according to new research from the Economic and Social Research Council (ESRC).

Health

Monday's medical myth: Peanuts stop motion sickness

At the start of The Hitchhikers Guide to the Galaxy, the ever-resourceful Ford Prefect buys four packets of salted peanuts, ostensibly to prevent motion sickness. We sometimes get them on flights too. But do they work or ...

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Planet

A planet (from Greek πλανήτης, from the verb πλανώμαι planōmai I wander), is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.[a]

The term planet is ancient, with ties to history, science, myth, and religion. The planets were originally seen by many early cultures as divine, or as emissaries of the gods. Even today, many people believe in astrology, which holds that the movement of the planets affects people's lives, although such a causation is rejected by the scientific community. As scientific knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects. Even now there is no uncontested definition of what a planet is. In 2006, the IAU officially adopted a resolution defining planets within the Solar System. This definition has been both praised and criticized, and remains disputed by some scientists.

The planets were thought by Ptolemy to orbit the Earth in deferent and epicycle motions. Though the idea that the planets orbited the Sun had been suggested many times, it was not until the 17th century that this view was supported by evidence from the first telescopic astronomical observations, performed by Galileo Galilei. By careful analysis of the observation data, Johannes Kepler found the planets' orbits to be not circular, but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some share such features as ice-caps and seasons. Since the dawn of the Space Age, close observation by probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology. Since 1992, through the discovery of hundreds of extrasolar planets (planets around other stars), scientists are beginning to understand that planets throughout the Milky Way Galaxy share characteristics in common with our own.

Planets are generally divided into two main types: large, low-density gas giants, and smaller, rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System. In order from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four gas giants, Jupiter, Saturn, Uranus, and Neptune. The Solar System also contains at least five dwarf planets: Ceres, Pluto (originally classified as the Solar System's ninth planet), Makemake, Haumea and Eris. With the exception of Mercury, Venus, Ceres and Makemake, all of these are orbited by one or more natural satellites.

As of June 2009, there are 353 known extrasolar planets, ranging from the size of gas giants to that of terrestrial planets.

This text uses material from Wikipedia, licensed under CC BY-SA