The graph shows that 36 km/s is the escape velocity of the solar system at the Earth. But if we do some calculations, we will get 42.1 km/s as the right answer. I have been checking all other escape velocities of the solar system at the different planets from the graph, and they match with the real values. But the Earth escapes velocities do not match. Am I missing something or is it wrong?


enter image description here

sqrt((6.674E-11*1.989E30 *2)/(149.6E9)) = 42126.918623693244 km/s

Plot of Voyager 2's heliocentric velocity against its distance from the Sun

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    $\begingroup$ Please show the calculations. "But if we do some calculations, we will get 42.1 km/s as the right answer." is not sufficient for a good stackexchange question. I'm not saying it's right or wrong, just that you can't just pull numbers out of the air. Show a link to a reliable source, or do the math here. $\endgroup$
    – uhoh
    Aug 2 '17 at 10:58
  • $\begingroup$ Are you ignoring the fact that the gravity assists added velocity/energy above what it initially had when leaving Earth? $\endgroup$ Aug 2 '17 at 11:10
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    $\begingroup$ The 42 km/s figure is corroborated by e.g. Wikipedia, en.wikipedia.org/wiki/Escape_velocity $\endgroup$
    – Hobbes
    Aug 2 '17 at 11:36
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    $\begingroup$ According to this related question the plot is incorrect at 1AU. $\endgroup$
    – Hobbes
    Aug 2 '17 at 11:38
  • $\begingroup$ Actually, your first sentence is wrong. The graph does not reach zero distance, it starts at some non-zero distance from earth (1 AU). $\endgroup$
    – Polygnome
    Aug 2 '17 at 12:01