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

Shields up to beat global warming

Might an enormous orbiting "shield" be one way to combat the rising temperatures around the world caused by elevated atmospheric carbon dioxide levels? Writing in the International Journal of Global Warming, a team in China ...

Image: Instant space selfies

How many times have you taken a selfie and posted it instantly to your favourite social media channel? The Mercury Transfer Module of the BepiColombo spacecraft, currently en route to Mercury, is equipped with three 'selfie-cams' ...

Asteroid mining not a million miles away

Work by a team of University of Adelaide scientists to perfect metal and mineral extraction processes is bringing the possibility of mining the wealth contained within asteroids closer to reality. But science fiction won't ...


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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