Business

Boeing deliveries fall again in August

Boeing experienced another big drop in plane deliveries in August, the company reported Tuesday, as the months-long grounding of the 737 MAX continues to hit the aerospace giant.

Business

Russia aims high with new passenger plane

Russia on Wednesday unveiled to clients its new MC-21 passenger plane, billed as a competitor to Boeing and Airbus even though the project has been stymied by sanctions and glitches with its predecessor, the Sukhoi Superjet.

Other

FAA puts out a call for pilots to test changes in Boeing jet

Federal safety officials are recruiting pilots from airlines around the world to test changes that Boeing is making to the flight-control software on the grounded 737 Max jet, according to two people briefed on the situation.

Energy & Green Tech

British startup looking to build 18-seat bioelectric hybrid airplane

British startup Faradair Aerospace has unveiled plans to build and sell an 18-seat bioelectric hybrid airplane for use as both a passenger and cargo air transport. The company is calling its plane the Bio Electric Hybrid ...

Engineering

Engineers fly first-ever plane with no moving parts

Since the first airplane took flight over 100 years ago, virtually every aircraft in the sky has flown with the help of moving parts such as propellers, turbine blades, and fans, which are powered by the combustion of fossil ...

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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