Skip to main content
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 ...
John's user avatar
  • 6,931
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 ...
Gordon Stanger's user avatar
20 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 ...
David Hammen's user avatar
  • 23.7k
18 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 ...
Gordon Stanger's user avatar
16 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 ...
John's user avatar
  • 6,931
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 ...
John's user avatar
  • 6,931
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 ...
Camilo Rada's user avatar
  • 17.7k
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 ...
Fred's user avatar
  • 24.7k
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 ...
Gimelist's user avatar
  • 23.1k
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 ...
njuffa's user avatar
  • 558
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 ...
dlb's user avatar
  • 626
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 ...
Douglas J E Barnes's user avatar
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.
John's user avatar
  • 6,931
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 ...
Camilo Rada's user avatar
  • 17.7k
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 ...
Knob Scratcher's 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 ...
Santiago's user avatar
  • 596
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 ...
Gordon Stanger's user avatar
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 ...
kingledion's user avatar
  • 3,376
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 ...
jeffronicus's user avatar
  • 3,489
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 ...
jeffronicus's user avatar
  • 3,489
5 votes
Accepted

If we could green the Sahara, would it be able to sustain itself?

The biggest detriment to keeping deserts green is of course water. With rainfall in the desert limited, afforestation is a tricky and potentially dangerous thing to do. China tried this for decades ...
LazyReader's user avatar
4 votes

Why are many fossils found in deserts?

Because there is nothing in the way. Looking for stuff in a jungle is difficult because of limitation of vision and difficulty of moving equipment and supplies. Looking for fossils in downtown ...
Chris Moore's user avatar
4 votes

In general, does the presence of vegetation increase/decrease gross water loss (evapotranspiration) compared to barren land (evaporation only)?

I think it is best to introduce some definitions. Often in such studies, two types of evapotranspiration (or evaporation, but I will stick to evapotranspiration during this answer for convenience) are ...
NiRo's user avatar
  • 126
4 votes

In general, does the presence of vegetation increase/decrease gross water loss (evapotranspiration) compared to barren land (evaporation only)?

In addition to what has been (correctly) written in the other answers, I would like to add a couple of figures that could help to understand the dynamics involved: The first figure is borrowed from ...
Nemesi's user avatar
  • 1,268
4 votes

Where did the sand in the Sahara come from?

Only 25% of the Sahara is sand and dunes. 70% of the Sahara is bare rock and stones. Un-watermarked version avaliable on www.alamy.com Silicon makes up 27 percent of rocks on average. The Sahara is ...
bandybabboon's user avatar
  • 1,349
4 votes
Accepted

What is this big Black Mass in Syria, as seen on google maps?

This is the Al-Safa Volcano in Syria. According to Wikipedia it last erupted in 1850 AD.
BillDOe's user avatar
  • 2,187
4 votes

How can the Simpson Desert be the largest sand dune desert in the world?

The linked Wikipedia article has been edited after the OP's question was posted. It now says: The Simpson Desert is a large area of dry, red sandy plain and dunes in Northern Territory, South ...
uhoh's user avatar
  • 7,070
4 votes
Accepted

Why is reverse osmosis desalination the dominant method used and not heat-based methods? Also why is brine being dumped back into the ocean?

Starting with question 2): you can use heat to evaporate the water but you need some sort of energy or thermal exchange to cool and condense it back to liquid. My understanding is that reverse osmosis ...
haresfur's user avatar
  • 4,419
3 votes

Desalination and Weather Impact?

Your first question, regarding salt pollution requires a back-of-an-envelope calculation. At present, about 4% of the global population relies, either wholly or in part, on desalinated water. Because ...
Gordon Stanger's user avatar
3 votes

In general, does the presence of vegetation increase/decrease gross water loss (evapotranspiration) compared to barren land (evaporation only)?

In general, evapotranspiration from vegetated areas is greater than the bare soil evaporation. You are correct that vegetation will increase the boundary layer and thus reduce evaporation at the ...
haresfur's user avatar
  • 4,419

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