Our cities have now been named as the saving places of a planet in crisis. And yet we cannot decide on the principles that make for a good city. Everybody has a view, but some views are more sustainable than others.
When you step outside your house, light from the sun means that the colour of everything changes. You probably haven’t even noticed it, because your brain helps you see colours the same way under most conditions.
The Tropics are defined as the area of Earth where the Sun is directly overhead at least once a year — the zone between the Tropics of Cancer and Capricorn.However, tropical climates occur within a larger area about 30 degrees either side of the Equator. Earth’s dry subtropical zones lie adjacent to this broad region. It is here that we find the great warm deserts of the world.
Earth is estimated to be around 4.5 billion years old, with life first appearing around 3 billion years ago.To unravel this incredible history, scientists use a range of different techniques to determine when and where continents moved, how life evolved, how climate changed over time, when our oceans rose and fell, and how land was shaped. Tectonic plates – the huge, constantly moving slabs of rock that make up the outermost layer of the Earth, the crust – are central to all these studies.
Humans may have had pet cats for as long as 9,500 years. In 2004, archaeologists in Cyprus found a complete cat skeleton buried in a Stone Age village. Given that Cyprus has no native wildcats, the animal (or perhaps its ancestors) must have been brought to the island by humans all those millennia ago.
Flexible foxes can be found in almost any sort of terrain. Indeed, one species, the red fox or Vulpes vulpes, is the most widely distributed land carnivore of all, ranging from the Arctic to North Africa. And where its rivals stick to the countryside, these foxes have made themselves at home in modern towns and cities. Why is this?
Most people say that if there is a healthy choice on a menu they will take it. But observations and research show this is generally not the case. Instead, people tend to make choices based on how food tastes. Typically, the more sugar, salt and fat in the food, the more we will like it. Genetics, experience and environment also influence our perception of food and the consumption choices we make.
Our ancient ancestors seem to have survived some pretty harsh arid spells in East Africa’s Rift Valley over five million years. Quite how they kept going has long been a mystery, given the lack of water to drink. Now, new research shows that they may have been able to survive on a small networks of springs.
Charles Darwin believed that humans evolved in Africa, because that’s where our closest ape relatives the chimpanzees and gorillas live. And during the twentieth century he was vindicated through a combination of fossil and genetic discoveries.
The U.S. Department of Energy spends US$3-$4 billion per year on applied energy research. These programs seek to provide clean and reliable energy and improve our energy security by driving innovation and helping companies bring new clean energy sources to market.
May and June are typically peak months for tornadoes in North America. We asked Penn State meteorology professors Paul Markowski and Yvette Richardson to explain why tornadoes form, how to stay safe if you’re near one and whether climate change is affecting tornado patterns.
The asteroid that struck Earth about 66 million years ago and led to the mass extinction of dinosaurs may have hit one of the worst places possible as far as life on Earth was concerned. When it struck, the resulting cataclysm choked the atmosphere with sulphur, which blocked out the Sun. Without the Sun, the food chain collapsed, and it was bye-bye dinosaurs, and bye-bye most of the other life on Earth, too.
NASA’s annual survey of changes in Arctic ice cover greatly expanded its reach this year in a series of flights that wrapped up on May 12. It was the most ambitious spring campaign in the region for NASA’s Operation IceBridge, an airborne mission to monitor ice changes at Earth’s poles, which also included a rapid-response flight over a new crack in Petermann Glacier, one of the largest and fastest-changing glaciers in Greenland.
If you could travel back in time 41,000 years to the last ice age, your compass would point south instead of north. That’s because for a period of a few hundred years, the Earth’s magnetic field was reversed. These reversals have happpened repeatedly over the planet’s history, sometimes lasting hundreds of thousands of years. We know this from the way it affects the formation of magnetic minerals, that we can now study on the Earth’s surface.
The amount of leopards in South Africa is declining rapidly, explicitly in the north of the country. In the past 10 years the leopard population has dropped as much as 66% near the border with Zimbabwe. According to Royal Society Open Science there are barely 4500 wild leopards left in the whole of South Africa.
It might seem unlikely, but tiny grains of minerals can help tell the story of early Earth. And researchers studying those grains say that 4.4 billion years ago, Earth was a barren, mountainless place, and almost everything was under water. Only a handful of islands poked above the surface.