Savannahs slow climate change, experts say

Tropical rainforests have long been considered Earth's lungs, sequestering large amounts of carbon dioxide from the atmosphere and thereby slowing down the increasing greenhouse effect and associated human made climate change. Scientists in a global research project now show that the vast extensions of semi-arid landscapes occupying the transition zone between rainforest and desert dominate the ongoing increase in carbon sequestration by ecosystems globally, as well as large fluctuations between wet and dry years.

Astronomers create first realistic virtual universe

Move over, Matrix -- astronomers have done you one better. They have created the first realistic virtual universe using a computer simulation called "Illustris." Illustris can recreate 13 billion years of cosmic evolution in a cube 350 million light-years on a side with unprecedented resolution.

Stars like the sun may end up alone but they are born in stellar nurseries, with a thousand — or a hundred thousand — siblings. Over time, the family disbands, victims of gravitational nudges and other tidings after 4.5 billion years of life in the cosmos.

Types of Mountains

Mountains make up a large proportion of the earth's surface. Based on their mode of formation, four main types of mountains can be distinguished.

1.     Fold mountains. These mountains are by far the most widespread and also the most important. They are caused by large-scale earth's movements, when stresses may be due to the increased load of the underlying rocks, flow movements in the mantle, magnetic intrusions into the crust, or the expansion or contraction of some part of the earth. When such stresses are initiated, the rocks are subjected to compressive forces that produce wrinkling or folding along the lines of weakness. Folding effectively shortens the earth's crust, creating from the original level surface a series of waves. The upfolded waves are called anticlines and the troughs or downfolds are synclines.

Earth Movements and the Major Landforms

The face of the earth is constantly being reshaped by the agents of denudation - running water, rain, frost, sun, wind, glaciers and waves, so that our present landforms are very varied and diverse. But these agents only modify the pattern of mountains, plateaux and pains which have been modelled by movements of the earth's crust.

Since the dawn of geological time, no less than nine orogenic or mountain building movements have taken place, folding and fracturing the earth's crust. Some of them occurred in Pre-Cambrian times 600-3500 million years ago. The three more recent orogenics are the Caledonian, Hercynian and