Related topics: nasa · satellite · earth · solar system · spacecraft

K2-25: An eccentric hot Neptune with the mass of seven Earths

Of the roughly 4,300 exoplanets confirmed to date, about ten percent of them are classified as "hot Jupiters." These are planets with masses between about 0.4 and 12 Jupiter-masses and orbital periods less than about 110 ...

The cost of space debris: In-space collisions increasingly likely

With hundreds of satellites launched every year, in-space collisions and the creation of fast-moving fragments of space debris—or 'space junk'—are becoming increasingly likely, threatening our continued human and technological ...

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Orbit

In physics, an orbit is the gravitationally curved path of one object around a point or another body, for example the gravitational orbit of a planet around a star.

Historically, the apparent motion of the planets were first understood in terms of epicycles, which are the sums of numerous circular motions. This predicted the path of the planets quite well, until Johannes Kepler was able to show that the motion of the planets were in fact elliptical motions.[citation needed] Isaac Newton was able to prove that this was equivalent to an inverse square, instantaneously propagating force he called gravitation.[citation needed] Albert Einstein later was able to show that gravity is due to curvature of space-time, and that orbits lie upon geodesics. This is the current understanding.

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