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Scientists find evidence of hydrocarbons in Earth’s upper mantle

admin — Sat, 01 Aug 2009 13:31:29 +0000

In a new research, scientists have found for the first time that ethane and heavier hydrocarbons can be synthesised under the pressure-temperature conditions of the upper mantle of the Earth.

The research was conducted by scientists at the Carnegie Institution’s Geophysical Laboratory, with colleagues from Russia and Sweden.

Methane (CH4) is the main constituent of natural gas, while ethane (C2H6) is used as a petrochemical feedstock.

Both of these hydrocarbons, and others associated with fuel, are called saturated hydrocarbons because they have simple, single bonds and are saturated with hydrogen.

Using a diamond anvil cell and a laser heat source, the scientists first subjected methane to pressures exceeding 20 thousand times the atmospheric pressure at sea level and temperatures ranging from 1,300 Fahrenheit to over 2,240 Fahrenheit.

These conditions mimic those found 40 to 95 miles deep inside the Earth. The methane reacted and formed ethane, propane, butane, molecular hydrogen, and graphite.

The scientists then subjected ethane to the same conditions and it produced methane. The transformations suggest heavier hydrocarbons could exist deep down.

The reversibility implies that the synthesis of saturated hydrocarbons is thermodynamically controlled and does not require organic matter.

The scientists ruled out the possibility that catalysts used as part of the experimental apparatus were at work, but they acknowledge that catalysts could be involved in the deep Earth with its mix of compounds.

“We were intrigued by previous experiments and theoretical predictions,” said Carnegie’s Alexander Goncharov, a co-author.

“Experiments reported some years ago subjected methane to high pressures and temperatures and found that heavier hydrocarbons formed from methane under very similar pressure and temperature conditions,” he said.

“However, the molecules could not be identified and a distribution was likely. We overcame this problem with our improved laser-heating technique where we could cook larger volumes more uniformly. And we found that methane can be produced from ethane,” he added.

According to Professor Kutcherov, a coauthor, “The notion that hydrocarbons generated in the mantle migrate into the Earth’s crust and contribute to oil-and-gas reservoirs was promoted in Russia and Ukraine many years ago.”

“The synthesis and stability of the compounds studied here as well as heavier hydrocarbons over the full range of conditions within the Earth’s mantle now need to be explored,” he said.

source: ANI

Global Warming

admin — Sat, 25 Jul 2009 14:44:56 +0000

The term Global warming refers to the gradual rise in the earth’s temperature. Global warming has been an environmental issue that has plagued the entire globe for a few years now and researchers have said that the global warming will cause a complete change on the planet, with the same catastrophic effects as the ice age. Small effects can be seen already in the North and South Poles, where the ice bergs are beginning to melt. There is also evidence of the sea levels rising in certain areas.

Global warming has been directly attributed to the hole in the ozone layer which is causing the heating up of the earth’s atmosphere from the sun. This is commonly referred to as the greenhouse effect. It is said that if the hole in the ozone layer continues to grow, global warming could accelerate quite dramatically. This is why many countries have come together and signed agreements to cut down on fuel emissions into the atmosphere and use various other forms of energy that are safe for the ozone layer.

Other causes that are considered to be contributing factors to the increase in the temperatures of the atmosphere are volcano eruptions since the mid 20th century and solar variations. Global warming will have other effects on the world as we know it, and

as one part of the climate changes, so other changes will occur. The average temperature of the earth has increased dramatically in the last decade or so, and as the temperatures get warmer, so the sea level will rise causing a difference in the amounts of precipitation that occur. This could mean that extreme weather conditions will develop like excessive storms with heavier rainfall and others. There is also expected to be slower summer stream flow, a difference in agricultural growth and harvest, as well as certain extinction of animal and plant species.

Most of the major scientific institutions blame the greenhouse effect and the greenhouse gases for the increase in global warming. The main greenhouse gases are methane, carbon dioxide, and water vapor. While water vapor and methane are not present for very long in the earth’s atmosphere, carbon dioxide can remain in the atmosphere for many years and when combined with the water vapor can escalate the rate at which global warming takes place. What happens is that the carbon dioxide increases the potency of the short term water vapor that is evaporated, which in turn causes more warming, and the cycle continues. This is the feedback effect and the only way to stop global warming is to remove the carbon dioxide that is present in the atmosphere already and definitely not add more to it.