146

This is an interesting question, but it lacks a key factor that is crucial to the answer: TIME. The point on Earth closest to the Sun varies through time, so the question can be asked about any moment in time, or over periods of time. Let's analyze the factors involved. At any given moment in time, the point on Earth's surface that is closest to the Sun is ...


80

The water in any river draining the sea is infinitely recycle-able (from rain replenishment), whereas the salt from any terrestrial source is not. So salty rivers, if any, won't exist permanently. Saltwater lakes gain their salinity precisely because they have no outlet, so salt just gets concentrated by evaporation. I don't think there are any truly saline ...


31

The already accepted answer is already covering the "real" answer as far as I'm concerned, and while you won't find many (any?) saline rivers in the traditional sense, we do have underwater "rivers" that kiiiiind of but not quite fit the bill. They're not saline rivers as I expect you envision, but I figure they could be an interesting "by the way though" ...


31

Probably a bit over 4 km, in this South African mine: https://en.wikipedia.org/wiki/Mponeng_Gold_Mine But as the link mentions, the mine operators go to considerable lengths to reduce the mine temperature to endurable levels from the 66°C/151°F of the surrounding rock. Note: This answer is for the original question, where the OP asked for the deepest ...


28

The main resistance that winds have to their movements comes from the topography and surface obstacles. Therefore, as a general rule the closer to the surface the less wind you will find. But I guess you are interested in the winds in areas clear of surface obstacles, otherwise the answer would a be a cave or a dense forest somewhere. To figure out what is ...


25

The Pecos River in Texas, USA may arguably fit the description of a "saltwater river". A point of argument is what is considered to be "saltwater". For comparison, here are some bodies of water and their salinity. 35,000 ppm Pacific and Atlantic Ocean 13,000-23,000 ppm Black Sea 12,500 ppm Caspian Sea 10,000 ppm Baltic Sea Note though, that salinity ...


22

Water from the Caspian sea, with a salinity of 1.2%, is constantly flowing into Garabogazköl, where the water eventually evaporates and leaves the salt behind. Of course, the situation is not indefinitely stable, as the depression is eventually going to be filled with salt. But at the time writing, water is still flowing like a river through the very narrow ...


21

There is an entire field of Geophysics called gravimetry dedicated to measuring the magnitude of the gravitational field. First, we should distinguish between weight (a force) and gravity (an acceleration). Gravity is the acceleration that Earth gives to objects near its surface due to the gravitational force. The acceleration of an object near the ...


19

Since you termed it based on sea level, the gold mines in South Africa are not the deepest, they begin at an elevation of ~1500 m, meaning their 4 km depth is only 2.5 km below sea level. The Kidd mine in Canada is 2.9 km deep and is located at an elevation of only ~250 m above sea level making it's depth 2.65 km below sea level. https://en.wikipedia.org/...


18

21.7%, by my calculations (338 / 1556 holocene-active volcanoes). I calculated perennial snow by combining 6 weeks of MOD10A2 data from winter and summer weeks in 2014 to figure out which pixels had snow both in the summer and the winter. My source code for that is available as a gist (an older version accidentally classified cloud as snow; that's been fixed)...


17

Here in New York City we have a salt "river". It is called the "East River" and it separates part of Long Island (Brooklyn and Queens) from the island of Manhattan and the mainland (The Bronx). Indeed it looks a lot like a salt river: From a hydrology perspective it is not a river tho, it is actually a saltwater estuary.


16

The Cascades (the volcanic range that Mt. St. Helens and Mt. Ranier are a part of) are "arc volcanoes" (a.k.a. "a volcanic arc", etc). Volcanic arcs form at a regular distance (and fairly regular spacing) behind subduction zones. Subduction zones are areas where dense oceanic crust dives beneath more buoyant crust (either younger oceanic crust or ...


16

To answer my own question based on the useful comments here, my favorite methods were: The earth's shadow cast on the moon during an eclipse. It is easy to observe and the flat earth counter argument is so insane that if it is offered you should just walk away. Shadows differ from place to place. The same experiment as Eratosthenes but you can carry this ...


15

Zoom in for the clues. The lines are not radiating out from the village, but from the cattle kraals. These kraals are irregular enclosures built of acacia thorn, agave and other thorny bushes. The cattle are kept in these kraals at night to protect them from hyenas and packs of wild dogs. The cattle themselves are likely African longhorn or various local ...


15

You generated multiple questions, I am going to list some of them. People can disagree with any of my answers, I made the estimations quickly. 1.Record depth in the rocks from the surface a person has reached. Based on your original question, jamesqf's answer of the mine in South Africa may be the deepest. 2.Record depth in the rocks from the surface a ...


14

I don't understand the last sentence about decimal places, but I can tell you about the relationship between lat, long and distance. Over two centuries ago, the meter was defined as one ten-millionth (1/10 000 000) of the length of a quadrant along the Earth's meridian; that is, the distance from the Equator to the North Pole. So, for latitude the number of ...


14

I'm sorry that this answer will be unsatisfactory and, strictly spoken, off topic, but I want to give it anyway. The answer is: You can't. Don't waste your time. Your relative has developed a paranoia. Not only is this not an isolated earth science issue; it is not even an issue with science at all. Instead, she has dismissed our common everyday frame of ...


14

The Atatacma desert comprise a very large area of more than 100,000 square kilometers, that host very different climates. The main factors driving the climatic variability are the distance to the Pacific ocean and elevation. This latter factor is very strong, as the Atacama desert covers a formidable elevation range, from sea level to almost 7,000 m, at the ...


14

Yes, there are many. According to the seafloor topographic data of ETOPO (1 arc second resolution), and the Exclusive Economic Zones (EEZ) database of marineregions.org. There are at least 157 seafloor features higher than -100 m (closer than 100 m to the sea surface). With that data, I made the following figure that shows: ETOPO topographic data All EEZ ...


13

So here is the way I do that personnally with NaturalEarth data and R (but you can do something similar i m assuming with any programming language that can deal with GIS or any GIS software): Fist download and unzip the file: download.file("http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/10m/physical/ne_10m_coastline.zip", "...


13

Factors determining the maximum possible height of mountains include the rate of uplift versus the rate of erosion[a] and rock strength. Rock strength is controlled by the type and internal structure of the rock in question. There is some evidence that once mountains extend above the snow line, glacial and periglacial erosion have a stronger control than ...


13

One example of an ore deposit that runs under a city is the banded iron formation ore in Kiruna. In this case the ore has been mined outside of the city since the turn of the previous century. The ore has been found to run under the city and there are now plans to move the city more detailed information. This has led to a process where the city has to be re-...


13

The Ural mountains are one of the oldest mountain ranges on Earth. They started forming about 300 Ma ago by the subduction of the oceanic crust once attached to the Kazakhstania plate under the ancient Laurussia continent. A subduction process that finished about 240 Ma ago. The tectonic plates are far from fixed, some of them disappear over time other new ...


12

From http://www.physicalgeography.net/fundamentals/8o.html and http://www.eoearth.org/view/article/154984/ The spatial distribution of ocean regions and continents is unevenly arranged across the Earth's surface. In the Northern Hemisphere, the ratio of land to ocean is about 1 to 1.5. The ratio of land to ocean in the Southern Hemisphere is 1 to 4. This ...


12

You might like to check World Cave List which has a pretty extensive list of caves, their depths, and lengths. For example: This list has been automatically produced from our World Caves Database. Total depth and length of all caves currently collected in the database: Number of caves = 2424 Caves deeper than 300m = 1075 Caves longer ...


12

If you don't want to do the calculation yourself, you can use an online calculator like the one provided by NOAA. Alternatively, if you do want to do the calculation yourself you can use the haversine formula. This uses the ‘haversine’ formula to calculate the great-circle distance between two points – that is, the shortest distance over the earth’s ...


12

I live near a river named Salz, flowing both warm and salty on the north slope of the Pyrenees south of Carcassonne. In historical times it was boiled dry for salt. See Les Sources de Salz


12

Checking the Wikipedia page on underwater volcanoes and listing them by height, I think the best candidate is Vema Seamount. Vema Seamount is in international waters and its shallowest point is at 11 meters from the surface. It is so shallow that it represents a navigation hazard.


11

One standard that has be used by the USA is to measure the distant between points on the coast at intervals of 30 latitude minutes, as measured on a 1:1,200,000 scale map. See chapter 5 of Measurements from Maps: Principles and Methods of Cartometry by D. H. Maling for further information and other standards that have been used.


11

(Fig. 2.4 of Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor) 8.3% of the Earth's surface is above 1 kilometer. This corresponds to about 29% of the land area. So 71% of the land area is below 1 km.


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