Kelly Prime

Most of those proposed ideas weren't given any real consideration.

For one, they were stupid.

But two, it was believed that if someone could find a solution to the longitude problem, that solution would probably come out of the field of astronomy.

That is, until an unexpected dark horse entered the race.

John Harrison was not an astronomer.

He was a self-taught clockmaker and the son of a carpenter.

This is Emily Ackermans at the Royal Observatory in Greenwich.

Her title is actually The Curator of Time, which sounds like the name of a Doctor Who episode, but is actually her job.

I met Emily in the observatory, surrounded by mysterious brass instruments and all the people coming to look at them.

Harrison, who worked alongside his brother James, took an outsider's approach in his clockmaking.

He invented new features like the gridiron pendulum and grasshopper escapement.

These terms might not mean anything to you unless you study clocks, but trust me, the horology crowd is probably freaking out right now.

That's because a solution to the problem of longitude at sea actually already existed, at least theoretically.

The best way I've found to imagine this is to think about our modern concept of time zones.

How many hours away something is can tell you roughly how far away that place is.

So I'm in New York and Roman's in California.

He's three hours behind me.

But Hawaii is five hours behind me, which means Hawaii is farther away than California.

So time can give a pretty good estimate of distance east and west.

So if you could get your local time using the sun overhead and you knew what time it was back home, you'd know the distance between those two places.