A few of us realized recently that it’s hard to picture the JOIDES (a 143 m ship) lowering a drill string over 4 km through the water and then drilling ~1500 m into the seafloor — the scales are just so different between this (relatively) small ship and the huge drill string.  So we decided to come up with some analogies to help visualize the difference in scale between our home on the sea and what it’s doing to get us these lovely cores.  Because seafloor drilling is kind of like being a big mosquito — we put the huge drill string down to pull up a 2.75″ diameter core — I figured that might be a good way to get a sense of scale.

So for a little math:

-The JOIDES is 143 m long

-Let’s assume we’re putting down 5500 m of drill string counting what’s in the water and what’s in the sediment

-Say a mosquito is about 1 cm long (though I’m told they’re about 5 times that size in the Upper Midwest and Ontario)

Then we have a conversion factor between the length of the ship/mosquito and the length of its drill string/proboscis (science word!) of ~1:38.5

So a 1 cm mosquito could bite you from ~39 cm or about 15″ away (click on the illustration above for a roughly to scale version of this terror-bug).  That’s…pretty far away…but not nearly as far as we thought originally.  This kind of exercise really helps put things into perspective that are hard to imagine.

And if a mosquito like that is still hard to picture, we can do the same thing with a person.  Let’s suppose we have a person who is 150 cm tall, or just under five foot.  Instead of commenting on the fact that they’re a bit on the short side, let’s now see how long their arms would have to be to retain the proportions of the JOIDES and its drill string:

150 cm x 38.5 = 5775 cm or 57 meters!  A football field (100 yards) is only about 91 m, so we’re talking a (shortish) person who could give you a shoulder massage from more than half a football field away!  That’s a terrifying image!  But it does help convey the sense of scale that we’re talking about.  We’re currently in a break between cores (which is why I can write about monster mosquitoes and mechanically unstable people), and I’m watching the TV screen that shows how deep the drill assembly is at the moment.  It’s slowing down around 4260 m, about at the sea floor, but without someway of contextualizing just how far down that is, it remains a number on a screen.

I hope this post won’t give anyone nightmares involving giant insects or disproportionate people, but instead conveys at least some sense of the different scales we’re talking about and that scales are definitely not just for fish (they’re for mosquitoes and people too!).

I might make a fly swatter to keep in the lab just in case…

Brian