Hot answers tagged

31 votes
Accepted

How do oases form in the middle of the desert?

Oasis are places where aquifers are connected to the surface. The source of the water in the aquifer however can be hundreds of miles away in areas that do get significant rainfall. The trick is ...
user avatar
  • 6,558
28 votes

Was Judea as desertified 2000 years ago as it is now?

There has always been a strong north-south rainfall gradient from approximately the Golan Heights (high rainfall), through Judaea and southwards into the arid Sinai desert. We know that this gradient ...
user avatar
19 votes

Why are many fossils found in deserts?

Bones don't last very long in jungles. Or in forests. Or almost anywhere. Fossils are the consequence of one highly unlikely fluke after another. Darwin himself commented on this. It takes just-right ...
user avatar
  • 20.5k
17 votes
Accepted

What are these lake-like blue patches in the desert, visible in satellite image?

The 'bluish' areas are exposed gypsum and gravel across which the sand dunes are moving. The colour is likely an artifact of the 'natural' colour palette used when processing the SPOT image. To ...
user avatar
17 votes
Accepted

What is this weird looking structure in Ethiopian desert?

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 ...
user avatar
15 votes

Why are many fossils found in deserts?

Because you find fossils by looking at exposed bedrock, deserts by their nature often have huge expanses of exposed bedrock. The lack of plants is also a big benefit, plant roots tend to destroy ...
user avatar
  • 6,558
14 votes
Accepted

Where did the sand in the Sahara come from?

The sand IS the original dirt, or at least what's left of it. Sand is one of the major constituents of soil. Soils are roughly half minerals by volume and those minerals are silt, sand, and clay. In ...
user avatar
  • 6,558
14 votes

What would be the effect of bringing seawater pipes to the Sahara desert?

This is an interesting question & I've been waiting to see what answers, if any, would be written. One affect of creating such a lake would be a localized increase in humidity in the vicinity of ...
user avatar
  • 21.8k
14 votes
Accepted

Is Atacama Desert cloudy or cloudless most of the year?

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 ...
user avatar
  • 17.1k
14 votes

How do oases form in the middle of the desert?

There are two types of oases: natural and human made. Natural oases form when springs, created when underground aquifers allow fresh water to pool or flow on the ground surface of deserts, creating a ...
user avatar
  • 21.8k
11 votes

Was Judea as desertified 2000 years ago as it is now?

tldr: It was also dry back then, which is why the people living there were rebels and not the rich elite. I'd like to add a few points to Gordon's answer. First of all, Masada is on the western edge ...
user avatar
  • 22.2k
11 votes
Accepted

Is this a former volcano in the Hamad Plateau, in the Syrian desert?

My Rand-McNally Atlas shows the signature for lava fields in that area. The elevations in Google Maps indicate concentric contour lines with only small differences in elevation, rising from 600m at ...
user avatar
  • 428
10 votes

How will climate change affect the extent of the Sahara Desert?

Based on past events supported by archeological finds climate change will affect it. Here is a short quote from an about.com referencing National Geographic "... recent excavations at the site ...
user avatar
  • 311
10 votes
Accepted

Large scale structures in the Sahara – what are they?

These features are created by the wind.You will note that the upper left portion has a small dark spot. This is known as Waw al-Namus, or the "Oasis of Mosquitoes." It has a path of material in the ...
user avatar
10 votes
Accepted

Why are many fossils found in deserts?

I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ...
user avatar
  • 626
9 votes
Accepted

Identifying a desert landform

Star dunes, caused by the prevailing winds coming from multiple directions. Take a look at these different dune types.
user avatar
  • 6,558
9 votes

What would be the effect of bringing seawater pipes to the Sahara desert?

Nevada is 286,367 km² in area. With a conservative average evaporation of 2500 mm/yr in your desert, a lake of that size would evaporate 22686 m3/s. That is a flow larger than the average river ...
user avatar
  • 1,673
8 votes

How will climate change affect the extent of the Sahara Desert?

Sahara greening is generally driven by the strength of the North African Monsoon, which follows the earth's orbital cycles pretty neatly. (Piquet's answer covers this). http://en.wikipedia.org/wiki/...
user avatar
  • 5,727
8 votes

What would be the effect of bringing seawater pipes to the Sahara desert?

I see three issues to be considered and will address them in what I think is reverse order of importance: 3) Cost: you have considered this with solar power and by trying to use mud to reduce ...
user avatar
  • 4,319
8 votes
Accepted

What percentage of Earth's surface is arid?

It will depend on the exact definition of "arid" and the period of time. But using the widely used and accepted Köppen climate classification, "arid" would correspond to the four climates in climatic ...
user avatar
  • 17.1k
7 votes

Where did the sand in the Sahara come from?

Minimum volumes of mobile sand can be estimated for each region of the Sahara, such as the 26 meter average thickness of the Erg Oriental of Algeria. Sand migration model conclusions regarding such ...
user avatar
7 votes

Is there a buildup of static electricity in a sandstorm?

Sandstorms occur in dry areas, particularly deserts. The sand particles are fairly uniform in size. As the dry sand moves due to the wind it begins a leaping process known as saltation. Quoting the ...
user avatar
  • 21.8k
7 votes

Is there any place on Earth that is permanently a desert?

UserLTK, above, has mentioned the Dry Valleys of Antarctica and the Atacama desert as two notable examples of "permanent" deserts. It's likely that these two locations have been deserts for at lease ...
user avatar
7 votes

Is Atacama Desert cloudy or cloudless most of the year?

Atacama desert is cloudless most part of the year. Except for the litoral, where a fog from the sea goes inland. This phenomena is called camanchaca. Telescopes for astronomy are located in high ...
user avatar
  • 516
6 votes

Was Judea as desertified 2000 years ago as it is now?

Gordon Stanger covers the climate aspects well in his answer, but I thought I'd chime in with an answer to the "was it as much a desert as it is now?" While I'm not aware of any archaeological ...
user avatar
  • 3,314
5 votes
Accepted

Does over-cropping large areas really change the amount of rainfall?

For an example of how bad agricultural practices can cause soil loss and end up with dust and sand, see the conditions that preceded the dust bowl in the USA. Certain crops are bad for soil and if ...
user avatar
  • 13.9k
5 votes
Accepted

When was the first not-icy desert formed?

Deserts have existed since at least the Permian period (299-251 million years ago) when the world's continents had combined into the Pangaea supercontinent. Stretching from pole to pole, this land ...
user avatar
  • 3,128
5 votes

Hypothetically, would digging a big trench from the ocean and flooding desert areas be a bad solution to combatting sea level rise?

Yes, it would be a bad solution. Aside from the construction and maintenance cost, the impact to the populations affected, and the impact on the environment around the destination, the benefits would ...
user avatar
  • 3,128

Only top scored, non community-wiki answers of a minimum length are eligible