# When I travel next, I want to reach the point on the earth that is exactly opposite my home, how can I discover where that is?

My wife and I are planning to travel to Japan next September (we are from Brazil). Since I was a child I have known that if I made a hole (a big one) straight down, I would reach Japan. Well, as the time passes every time I look at the ground, I imagine that far, far away there it is, Japan. Now that I'm going to Japan, I would like to know for curiosity (and to perhaps reach this place in my travels), the exact point in Japan that represents the place that, if I could dig a very big hole directly down from my house in Brazil, I would find in Japan.

So, is there some tool online that could help me? Is there some way to easily find this place using my home coordinates?

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This question appears to be off-topic because it is about geometry, not travel. It might be better at math.stackexchange.com. – Nate Eldredge May 1 '14 at 13:49
@NateEldredge I disagree. The antipode of my address is on my bucketlist – user141 May 1 '14 at 13:55
You can reach literally anywhere depending on the angle you're digging at. – gerrit May 1 '14 at 14:25
@gerrit sure, but he asked for 'exactly otherside'(sic) - not any old angle. – Mark Mayo May 1 '14 at 14:28
I'm still upset I didn't go to the small town in Spain directly opposite Christchurch, New Zealand :/ – Mark Mayo May 1 '14 at 14:28

It's very easy, and a quick google search for 'antipode' and 'map' will find sites that find it for you.

For example, Antipodes Map either detects your location, or you can enter one, and it'll show you on a zoomable map where your antipodal destination is.

Unfortunately as shown by the map above, only about 15% of land territory is antipodal to other land, and only a tiny fraction of Brazil is antipodal to Japan (in fact, to the islands of Okinawa and Amami). A rather larger amount of Brazil (but still a small fraction of the country as a whole) is antipodal to the Philippines and Indonesia, along with Brunei, parts of Malaysia and the South Korean island of Jeju. Without knowing your exact location I can't be sure where it ends up. I'll leave that last step up to you!

Another "Map Tunneler" site shows it quite nicely side by side. I can click and zoom in on New Zealand and the other window zooms in at the same time to show me northern Spain - the antipode.

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Antipodes Location: Most likely the ocean. Watch out for sharks. Unfortunatelly, I wont be able to reach the point :(... – Diogo May 1 '14 at 14:48
Better not dig the hole, then. You'll flood your home! – starsplusplus May 2 '14 at 13:08
If your antipode is in ocean and you intend to visit it anyway, do so in a boat so as to be safer from the sharks. – hippietrail May 4 '14 at 7:37
Note that Australia is the "Bermuda Triangle" of the Southern hemisphere. – Russell McMahon Sep 15 '14 at 14:59
Here's a slightly bigger tool: ubasics.com/dighole – Adam Davis Apr 21 '15 at 16:00

Yes the lat/lon coordinates are your friend. Lets assume the following coordinates are yours: S 9° 17' 42", W 51° 19' 17". You are 9 degrees south of the equator. Your antipode will be 9 degrees to the North. Just replace the S by the N and you have the latitude of your antipode (N 9° 17' 42'').

You are 51° 19' 17" away from the Greenwich line. Which mean 51 degrees, 19 minutes and 17 seconds. 1 degree contains 60 minutes and 1 minute contains 60 seconds. To get the longitude of your antipode, you'll need to do a bit more math. The antipode will be 51° 19' 17" away from the 180° longitude. To get the longitude which is relative to the Greenwich line, you need to subtract your longitude from the 180 line. It will become E (180-51)° (60-19)' and (60-17)''

``````180    0     0
51   19    17
``````

You don't want to have negative minutes and seconds, so you borrow a degree and subsequently a minute:

``````179   59    60
51   19    17
===============
128   40    43
``````

It appears that the antipode of the center of Brazil is close to the Philippines.

There are a multitude of online calculators to identify your antipode just google search for them, but I prefer the pencil paper calculation due to its simplicity. Also using a calculator without explanation on how the location is derived feels like falling for tourist traps ;)

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Given that you probably have to use the internet to find your own latitude and longitude, using pencil and paper seems way more complicated than just doing the whole thing online. – David Richerby May 1 '14 at 16:30
Yes, doing it by hand is insane and way way more complicated. It is also really cool though! ;-) – Ant May 1 '14 at 16:34
@DavidRicherby Nah a gps unit suffice – user141 May 1 '14 at 18:09
@andra: The answer may look great and you may prefer the pencil paper calculation, but it is obviously not that simple, since your calculations are wrong. The correct longitude is E 128° 40′ 42.168″. – Tor-Einar Jarnbjo May 1 '14 at 21:39
@Tor-EinarJarnbjo Oops I forgot to consider the minutes and seconds. Thanks for noting I edited my answer and provided the full calculation. For you it might not look simple, but now you have the provenance ;) – user141 May 2 '14 at 7:57

Use the Map Tunneling Tool. Unfortunately you won't reach any islands in Japan unless you live close to the Uruguay border.

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Find a globe. Put your arms out front with the forefingers pointing in. You are now a human calliper. Bring the arms together to nip the globe such that the left finger touches home. The right finger is now on the target.

Rotating the globe might help, unless you're a gymnast.

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:) +1 Brilliant answer!!! That is what i call the egg of columbus – user141 May 2 '14 at 9:19
For best results, use a globe whose diameter is the distance between your shoulders, so that your forefingers are parallel. – starsplusplus May 2 '14 at 13:22
NatGeo used to publish (I grew up with one purchased in the early 1970s) a globe that was sitting loose in a stand rather than bolted on at the poles. The stand had a ring that would match up to the equator if the globe was oriented with a pole directly up. That made it easy to visualize great circle paths by simply rolling the globe until the desired end points were both aligned with the ring. Finding Antipodal points was easy with it because the ring was also marked in degrees. – RBerteig May 3 '14 at 0:01
That's going to be so staggeringly inaccurate as to be worthless. I doubt you could estimate the antipodal point to better than a thousand miles using that method. – David Richerby May 3 '14 at 11:56
@DavidRicherby Accuracy suffers, but your odds of actually getting a piece of land increase exponentially and it's kid of fun which is probably the main point. – Sylverdrag Mar 3 '15 at 6:44

Wolfram Alpha could help here as well.

For example, typing in antipode of London, UK shows a map with a point south of New Zealand.

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The Google Earth application makes this really easy, no searching or math required. Just choose tools->ruler. Zoom in on your home and click to begin measuring. Zoom out and rotate the globe until the ruler starts spinning around the globe in circles. Zoom in on that spot and keep moving the ruler until you're as close as you want to get, then note the coordinates.

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