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

LightSail 2 is sending home new pictures of Earth

LightSail 2, the brainchild of the Planetary Society, has released two new gorgeous images of Earth. The small spacecraft is currently in orbit at about 720 km, and the LightSail 2 mission team is putting it through its paces ...

New hard X-ray eclipsing polar identified

Using ESA's XMM-Newton and NASA's Swift spacecraft, astronomers have found that a hard X-ray source known as 2PBCJ0658.0-1746 is an eclipsing magnetic cataclysmic variable of the polar type. The finding, presented in a paper ...

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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