Excellent question. Generally (heh), it’s best to try to look up an answer, especially if the answer is a short one-liner. I refer to those as “Jeopardy” questions. If the answer is short enough that it would fit on the Jeopardy board and someone could divine the question, you probably should look it up.
GQ is best for things that require a longer answer or more explanation.
So for this OP, I’d say “What is the deepest point in the ocean” is a Jeopardy question, whereas “Is the water warmer” is more GQ.
That said, there is no rule against Jeopardy questions.
Actually, the sea is highest in the middle of the oceans. Heights and depths are generally measured from a given datum called “sea level” (I think it’s the average level of the entire sea surface). But in the N Atlantic for instance, the ocean has a clockwise current running up the East Coast of the US (Gulf Stream) across the northern part of the ocean, down the Western side of Europe and back across to the Caribbean, north of the equator. This swirling (I believe because it is combined with the coriolis force which causes things to appear to move to the right in the northern hemishphere) causes water to pile up in the middle of the ocean, increasing the “height” of the local water by several feet.
You’re of course right that if you measured the height of the water column itself, it’d be the most over the trench, but in general, elevations and depths are measured from “sea level”.
Maybe I’m misinterpreting Permission to Engage, Sir’s post, but I think he is talking about height above “sea level”. Since rock is denser than water, its gravitational attraction is greater for a given volume. Thus water above the Marianas Trench would experience slightly less gravitational attraction than any other place on the ocean’s surface since it has more water and less rock underneath it than anywhere else.
The dive to the bottom of the trench was in 1960 aboard the bathyscaph Trieste. The crew was Jacques Piccard and Navy Lt. Donald Walsh. Walsh is still active in ocean science and writes a sea science article for the naval magazine Proceedings from time to time.
There was, at a place I worked, a gorgeous girl named Mariana.
The boss of our department once asked how deep the Marianas Trench was.
Myself and my co-worker both went into a trance. My boss, immediately realizing what we were thinking of, rolled his eyes and said “God, you guys!”
You may now go back to your regularly scheduled thread.
Believe it or not, there’s been a satellite (TOPEX/Poseiden) that measured, among other things, the average height of the ocean all over the world. Here’s a map with the results.
From the looks of it the highest area is in the northern Atlantic around Iceland and Greenland while the lowest is in the Indian Ocean near India.
**So, is sealevel higher on the Gulf side of the Panama Canal? **
Would the water natually flow down to the Pacific if it were somehow dug down to sealevel?
I beleive so, and this was apparently used as an argument against a 1950s plan to build a sea-level canal through the isthmus. Lifeforms from the Atlantic shore would mix with those from the Pacific shore.
Not that this objection would have actually stopped the plan–this was the fifties after all. The fact that they wanted to excavate the sea-level canal with nukes was the thing that actually killed the plan off…
As it is now, the canal is filled by fresh water from the mountains, which flows downhill towards both oceans. Apparently they’re having a bit of trouble getting enogh wwater these days because with deforestation the rainfall is decreasing.
i still think it’s odd that there’s no official record of anyone going back to the marianas trench since 1960. just the chance to be a part of history alone should have sent some submariner back there, not to mention additional scientific research. the first expedition had to return to the surface before the sediment could settle so they didn’t get a chance to see anything.
Read “The Hunt For Red October” By Tom Clancy. This was a major corridor for Soviet Era submarine traffic. The SOSUS worldwide network of hydrophones was designed to monitor areas like this. Careful acoustic signature analysis allowed us to not only precisely identify individual Soviet submarines but track migrating whales as well. You can be pretty sure that the Kursk episode was monitored by this listening array.
I would assume that the seas of northern Japan near Vladivostok are also heavily monitored.
Ah, but Joe Internet CAN find that out, to a resolution of a kilometer or two, if memory serves. The Man, however, would like to reserve the right to knowing whether to turn left or right at the black smoker on the valley floor.
In all seriousness, the details of the seafloor down to a few meters resolution has great value for submarine operators, both in terms of defending one’s own bit of the continental shelf/slope and sneaking onto someone else’s. The US Navy likely has very detailed maps of the Norwegian Sea, Arctic Ocean and Sea of Ohkhotsk (for example), but letting Joe Internet see them would also spill the beans to Ivan… kind of ruins any advantage the Navy might otherwise have.
Ok, one more question (as I said, this is really neat… undersea maneuvers requiring resolution in meters, holy cow). What’s to stop Ivan from getting his own maps, particularly if it’s his continental shelf? I mean, I could imagine that at some point, we wouldn’t want to do Ivan’s work for him, but eventually, even The Man has to admit that Ivan is going to map his own land. Ahh, just thought of another question (sorry)–are the continental shelf maps near the U.S. kept secret, or are they out there in blazing resolution, too? I know I should check the links myself, but you have no idea how slooooow my link at work is.
