Sciene & technology
What is fracking? Fracking or hydraulic fracturing is a method utilized by oil and gas companies to increase production of oil or gas from a well that would otherwise exhibit a low flow rate usually due to the geologic rock formation being too dense to allow for the economic recovery of hydrocarbons. These low permeability formations generally include tight sands, shales and coal bed methane deposits. Fracking consists of pumping millions of gallons of water, sand and various toxic chemicals (known as fracking fluids) thousands of feet down a well and out into the oil or gas bearing geologic rock formation at high enough pressure sufficient to cause that formation to fracture or crack. These fractures can extend hundreds of feet from the wellbore. After the desired fracking has occurred, the pumping of fracking fluids ceases and the internal pressure of the rock formation (the formation pressure) causes the injected fracking fluids to return to the surface (this is known as flowback). Frequently asked questions
learning & teaching
The World of Seven Billion The map shows population density; the brightest points are the highest densities. Each country is colored according to its average annual gross national income per capita, using categories established by the World Bank (see key below). Some nations— like economic powerhouses China and India—have an especially wide range of incomes. But as the two most populous countries, both are lower middle class when income is averaged per capita.
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Professor Ian Morison 1) Evidence of Dark Matter in Galaxy Clusters The first evidence of a large amount of unseen matter came from observations made by Fritz Zwicky in the 1930's. He studied the Coma cluster of galaxies, 321 million light years distant, and observed that the outer members of the cluster were moving at far higher speeds than were expected. The Invisible Universe
Humans are good at a lot of things, but putting time in perspective is not one of them. It’s not our fault—the spans of time in human history, and even more so in natural history, are so vast compared to the span of our life and recent history that it’s almost impossible to get a handle on it. If the Earth formed at midnight and the present moment is the next midnight, 24 hours later, modern humans have been around since 11:59:59pm—1 second. And if human history itself spans 24 hours from one midnight to the next, 14 minutes represents the time since Christ.