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

Earth's magnetic poles could start to flip. What happens then?

As Earth's magnetic shield fails, so do its satellites. First, our communications satellites in the highest orbits go down. Next, astronauts in low-Earth orbit can no longer phone home. And finally, cosmic rays start to bombard ...

First evidence of planet-wide groundwater system on Mars

Mars Express has revealed the first geological evidence of a system of ancient interconnected lakes that once lay deep beneath the Red Planet's surface, five of which may contain minerals crucial to life.

Researchers track Chinese space station as it falls

A defunct Chinese space station, Tiangong-1, is expected to fall to Earth any day now—on March 31, give or take a few days. When it does, it will be the largest manmade object to re-enter Earth's atmosphere in a decade.

New evidence for existence of Planet Nine

A large international team of researchers has found what they are describing as more evidence of the existence of Planet Nine. In their paper posted on the arXiv preprint server, the group describes the behavior of a newly ...

Mars terraforming not possible using present-day technology

Science fiction writers have long featured terraforming, the process of creating an Earth-like or habitable environment on another planet, in their stories. Scientists themselves have proposed terraforming to enable the long-term ...

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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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