2014年2月27日星期四

The new method Cheap Fut 14 Coins relies

The new method Cheap Fut 14 Coins relies on the clock-like regularity of a class of neutron stars called pulsars, the rapidly spinning remains of massive stars that died in supernova explosions. Pulsars shoot tight beams of radio waves into space that sweep across the sky like a lighthouse, so from Earth they appear to blink or pulse.

Because the Earth is always moving around the sun, the time it takes for these radio blips to reach us is Fifa 14 Coins PS3 always changing. To get rid of this effect, astronomers calculate when the pulse should reach the solar system centre of mass, or barycentre -- the point around which all the mass in the solar system moves. But because the planets arrangement around the sun is constantly changing, the barycentre moves around with respect to the sun, too.

To pin down the centre of mass at a given time, astronomers use a special table of where all the planets are, called an ephemeris, plus values for the masses of the planets taken from previous space missions. If the masses are slightly wrong, then a regular, repeating pattern of timing errors appears in the pulsar data. For instance, if Jupiter mass is a bit off, then an error appears every twelve years, once for every time Jupiter orbits the sun. Correcting the value for Jupiter mass makes the error disappear.

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