An international team led by researchers at Nagoya University, along with US and Swiss colleagues, has identified a new type of solar event and dated it to the year 5480 BC; they did this by measuring carbon-14 levels in tree rings, which reflect the effects of cosmic radiation on the atmosphere at the time. They have also proposed causes of this event, thereby extending knowledge of how the sun behaves.

When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth's atmosphere. Because carbon in the air is absorbed by trees, carbon-14 levels in tree rings actually reflect solar activity and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.

Read more ...

When Penn State decided to convert its two power plants from their historic use of coal as a source of energy to natural gas, there was concern about radon emissions. Although radon is known to exist in natural gas, now Penn State research indicates that it does not escape from these two power plants in harmful amounts.

By converting the West Campus Steam Plant on the University Park Campus, Penn State reduced its greenhouse gas emissions at the plant by nearly 40 percent, but the University wanted to make sure that the conversion was not causing a significant increase of radon levels in the atmosphere. Penn State also operates a second power plant on the East end of campus near its football stadium.

Read more ...

With new methods of reconstruction, climate researchers in Bern have been able to demonstrate that some 9,000 to 5,000 years ago, the Mediterranean climate was considerably warmer than previous studies had suggested. Among other things, previous concerns regarding the reliability of climate models could thus be dispelled.

Climate reconstructions are necessary because reliable measurement data are only available for the last 150 years. For this reason, research on past climate change uses so-called ‘proxies’. These are indicators with which it is possible to reconstruct temperatures in the past. A widespread reconstruction method examines pollen which is embedded in lake sediments. From the composition of this pollen, it is possible to determine the plant species which occurred at a particular location in the past – and since the temperatures that the individual species require are also known, it is possible to reconstruct the temperature conditions for the period in question.

Read more ...

The development of agriculture is universally believed to underpin some of the most significant advances made by humans worldwide. In New Guinea, where one of the earliest human experiments with tropical forest agriculture occurred, researchers have cast doubt on two views about the origins of agriculture.

Read more ...

More Articles ...

Subcategories