Take me to Null Island

There's a scene in Seinfeld that I've loved since I was a kid, and now I finally get to use it as an astronomy teaching tool.

Kramer's lost. He calls Jerry on a payphone. Jerry asks where he is:

Kramer: “I’m on 1st and 1st. How can the same street intersect with itself? I must be at the Nexus of the Universe!”

Roll the clip...

Kramer may have found it weird to be at the corner of 1st and 1st, but what if you found yourself at the corner of 0 and 0?

No Location = A Location

My friend Jonah posted a story on Instagram a few days ago. From what I gather, he was on a plane to Los Angeles and looked at the location on his phone.

What did the map show? Something like this:

Did the pilot take a wrong turn? Were they actually at the South Atlantic Ocean, below Ghana?

No. But why did it show his location here in the middle of the ocean?

My web design past roars back

I'm super familiar with this exact spot as I've seen it over and over in my web design career.

Many times, I've had to build sites with locations on a map. If you have no location coordinates – NULL coordinates – this is often where the default pin is set. 

But why here?

This spot on Earth is where the latitude is 0° and the longitude is 0°.  "How can the same map lines intersect with itself? I must be at the Nexus of the Planet!"

You can find the position of any place on Earth with these two numbers.

Latitude

Latitude measures how far north-south you are.

If you're at the Equator, we say you're at 0° latitude. If you go north 1°, we say your location is 1° N, and if you go south, you're at 1° S.

So, this place is at the Equator (notice the dashed line in the map above indicating that).

Longitude

Longitude measures how far east-west you are. 0° is at a location called the Prime Meridian.

It's not in the map above, so I've added here in the red dashed line:

If you're on this line, we say you're at 0° longitude. If you go east 1°, we say your location is 1° E, and if you go west, you're at 1° W.

Putting these two ideas together, we can pin down Montreal's location to 45°.5 N and 73.5° W.

Longitude is Arbitrary

There's no controversy in saying where the Equator is: it's at the halfway point between the North Pole and the South Pole. There's no debate to be had about where the halfway point is with latitude.

Longitude is a different story. That vertical red line in the map above is a completely arbitrary line. For lack of a better term, it's not "naturally occurring".  

We call this line the Prime Meridian.

The Prime Meridian runs through the Greenwich Observatory, located in London, England. This location was decided in October 1884 at the International Meridian Conference (yes, this sounds like a 99% Invisible or Radiolab episode just waiting to happen).

It surprises me how recent this is! I seriously thought it would have been a date in the 1500s or something, but nope. Very recent.

You can read the Wikipedia page for the full details, but other countries also suggested the line run through their cities, but lost the vote to England. 

So the coordinates 0° latitude and 0° longitude are only in the middle of the South Atlantic Ocean because of a human decision.

Alternate Prime Meridian

Just imagine that instead of London being chosen as the Prime Meridian, it was Rome. Here is where the point 0° and 0° would be:

In one alternate timeline, the default spot for GPS coordinates could have been in the country of Gabon, nestled somewhere in Ivindo National Park:

But nope: history went one way and the intersection of 0° and 0° is in the middle of the water. But that didn't stop us from giving this spot a name: Null Island.

Null Island

The nearest land to this spot is about 600 kilometres away.

0° and 0° is pretty remote, however a weather buoy named "Soul" is permanently stationed there. It's part of a network of buoys used to track changing climate.

Fun fact: each buoy is named after a musical genres and dances. Other names include "Reggae", "Samba", and "Waltz".

In conclusion: if you see your GPS coordinates somewhere off the coast Ghana and you didn't have plans to be there, fear not. Your map just has no location and has put NULL values in place there.