All aboard the Gravity Express! Mystery Cache
All aboard the Gravity Express!
-
Difficulty:
-
-
Terrain:
-
Size: 
(micro)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
The published co-ordinates are for Cranbury House, the place where Sir Isaac Newton lived in later life until he died in 1727. To find the cache (which is just outside of the Cranbury Park estate), you will need to take an imaginary ‘gravity train’, an idea which goes back to the 17th century when the British scientist Robert Hooke FRS wrote to Sir Issac Newton about the concept.
Basically, a gravity train relies on a straight line tunnel being bored through a planet (not necessarily through the centre) connecting two places on the surface. At the start, the train would 'fall' into the tunnel and accelerate solely due to gravity, reach maximum velocity at the halfway point (which would be 17,671 mph if going through the centre of Earth) and then slow down as it continues on the other side, eventually coming to rest at the destination without the need for braking (due to gravity progressively slowing the train as it moves away from the mid-point of the tunnel back towards the surface). Thus providing energy free long distance travel! This of course depends on overcoming certain physical properties to do with friction, density, heat, pressure and (if the planet has an atmosphere) there being an absolute vacuum in the tunnel, but apart from that… you get the idea.
Curiously, all journeys on a gravity train take 2,532 seconds (42 minutes 12 seconds) irrespective of the distance travelled (London to New York, or Chandler's Ford to Southampton, for example – would take exactly the same time), which is handy for timetabling. For anyone wanting a more in-depth explanation of a gravity train, there is an interesting article here: [clicky]
To find the cache, you need to go to the northern terminus of the antipodal Gravity Express train which departs from S 51° 00.043 E 178° 38.719 (just off the Campbell Escarpment in the South Pacific Ocean, SE of New Zealand).
You are looking for a 35mm film pot so you'll need to bring your own pen. Waypoint averaging has been used to set the co-ordinates, but tree cover could be problematic, especially at certain times of the year.
You can check if you’re heading for the correct destination on the Gravity Express Geochecker:
Congratulations to SeekingSalters for the FTF 
Additional Hints
(Decrypt)
Chmmyr: k° A/F l° R/J ↦ k° F/A (180 − l)° J/R
Pnpur: Fvyire Ovepu, 4sg (vfu) hc