In the Atlantic Ocean, about a thousand miles
west of Africa, is Null Island. It's a busy place: Thousands of people live
there, millions of photos have been taken there, and occasionally, people teleport in
for just a moment or two before disappearing to somewhere else. Or at least, that's what it looks like to
a computer. Because if you actually set sail for Null
Island, you’d find nothing but deep blue ocean and a lonely weather buoy. Or boo-ey, if you’re American. There is one special thing you might notice:
it’s at exactly zero degrees longitude and zero degrees latitude -- and that’s the
key to why computers think this particular patch of ocean is a busy place. Any big database, whether it's storing information
about people, photos, or cats, needs to know the difference between “nothing”, like
zero, and nothing, as in, there’s no data, it’s a mystery. That idea of “no data” is called “NULL”. So here we know that Ser Pounce has black
fur, and Mr Sniffywinkles has brown fur, but we don’t know about Schrödinger. NULL doesn’t mean “no colour” or “no
fur at all”. It literally means "there is no data here,
we don’t know what color her fur is". This isn’t just a cat-related problem. If your phone doesn’t know where you are,
it might tag a photo you take with latitude NULL and longitude NULL, or it might tell
an app that your location is NULL, NULL. No problem so far. But badly written apps can read that as co-ordinates
“zero, zero”: they’ve mistaken nothing for “nothing”. So they’ll think that you are on Null Island
-- at least until your phone works out where you really are. More seriously, in a 2012 US election, many
voters in Wisconsin lived in places that the Census Bureau didn’t have co-ordinates for. So a new, automatic system said they lived
on Null Island… which is definitely not in any Wisconsin election district. If the mistake hadn’t been caught in time,
they might have had problems voting. You can also get problems when you try to
put the actual word "null" into a database, like you might try to do if you’re one of
the 300,000+ people with “Null” as your last name. It only takes a small programming error -- mistaking
“Null” for NULL -- and suddenly, the computer thinks you don’t exist, or at least you
can't register an account with your favorite kitty-litter-cleanup-service. All this is a reminder that our world is complicated,
and it’s not always as easy as you might think to map our messy reality into a computer
system. So the next time you see a photo tagged way
out in the Atlantic Ocean, you’ll know what’s happened. Unless it really is a photo of that one, lonely
weather buoy. Boo-ey. Whichever. Hey, this is Henry. First, I’d like to say thanks to Tom Scott
of the amazing youtube channel, Tom Scott, for helping write and narrate this video. And also thanks to Audible for supporting
MinuteEarth – Audible is a leading provider of audiobooks including fiction, non-fiction
and periodicals, and they’re offering free 30-day trials for our viewers at Audible.com/minuteearth. I’d like to recommend the book Predictably
Irrational by Dan Ariely, exploring various ways that humans reliably make irrational
decisions (like, how we’re often willing to put way more effort to get something that’s
free than the free thing is actually worth). Predictably Irrational is available on Audible,
and by using the free promo at Audible.com/minuteearth you help support MinuteEarth. And don’t forget to check out Tom Scott’s
brilliant other videos on his channel, Tom Scott.
