Sunday, February 18, 2018

astronomy - How is it the Voyagers are a few seconds closer to Earth than earlier?



The Voyager 2 tweet of March 01, 2013 put it's distance at 14 hrs 04 mins 23 secs of light-travel time from Earth. A more recent (earlier today) tweet says it is 14 hrs 04 mins 22 secs of light-travel time from Earth. An older tweet put it still further out at 14 hrs 04 mins 25 secs of light-travel time.


The Voyager 2 tweets on Voyager 1's proximity to Earth too has reduced similarly to 17 hrs 07 mins 07 secs of light-travel time earlier today from 17 hrs 07 mins 11 secs of light-travel time reported on Feb 28 2013


It could quite simply be a typo ... If not a typo then my curiosity is piqued; I was under the impression the Voyagers are outbound from the Solar System now without any major in-system activities now.


How is it the Voyagers are closer to Earth than before?



Answer



"Note: Because Earth moves around the sun faster than Voyager 1 is traveling from Earth, the distance between Earth and the spacecraft actually decreases at certain times of the year. " - quoted from http://voyager.jpl.nasa.gov/where/index.html


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