4 . We Have a Painter to Thank for Yellowstone

Before artist Thomas Moran set foot in the park, it was seen as an unhappy place. After, it was marketed as a wonderland.

Before Thomas Moran arrived, Yellowstone in the popular imagination was a harsh (严酷的), wild place pocked with hellish geysers(间歇泉). After the painter’s work was finished, Yellowstone was established as a national park and marketed as a wonderland.

In 1871 Moran and photographer William Henry Jackson had joined the first U.S. government survey of the region. For two weeks Moran filled a sketchbook (写生簿) with the landscape’s most stunning sights. The survey results, Jackson’s photos, and Moran’s watercolours—the first colour renderings of the area—were presented to Congress that fall. “The photographs were proof that what the artist was showing really existed,” says Eleanor Harvey, senior curator (馆长) at the Smithsonian American Art Museum.

In March 1872 lawmakers officially made Yellowstone a national park, the world’s first. By April, Moran had transformed some of his sketches into a 7-by-12-foot painting. The gold-splattered valley and billowing Lower Falls of “The Grand Canyon of the Yellowstone” attracted the public. “It is too grand and wonderful for words,” declared the Ladies’ Repository that August, “and none can ever judge of its wonders from any engraving or photograph in mere black and white.”

Though Moran later painted Lake Superior, the Grand Canyon, and the Rockies, his reputation was so intertwined with Yellowstone that he took to signing his paintings “TYM,” for Thomas “Yellowstone” Moran.

7 . Until relatively recently, the vast majority of human beings lived and died without ever seeing a city. The first city was probably founded no more than 5,500 years ago.     1    . In fact, nearly everyone lived on farms or in tiny rural villages. It was not until the 20^th century that Great Britain became the first urban society in history – a society in which the majority of people live in cities and do not farm for a living.

Britain was only the beginning.     2    . The process of urbanization----the migration of people from the countryside to the city----was the result of modernization, which has rapidly transformed how people live and where they live.

In 1990, fewer than 40% of Americans lived in urban areas. Today, over 82% of Americans live in cities. Only about 2% live on farms. The rest live in small towns.

Large cities were impossible until agriculture became industrialized. Even in advanced agricultural societies, it took about ninety-five people on farms to feed five people in cities.     3    . Until modern times, those living in cities were mainly the ruling elite and the servant, laborers and professionals who served them. Cities survived by taxing farmers and were limited in size by the amount of surplus food that the rural population produced and by the ability to move this surplus from farm to city.

Over the past two centuries, the Industrial Revolution has broken this balance between the city and the country.     4    . Today, instead of needing ninety-five farmers to feed five city people, one American farmer is able to feed more than a hundred non-farmers.

8 . By the end of the century, if not sooner, the world’s oceans will be bluer and greener thanks to a warming climate, according to a new study.

At the heart of the phenomenon lie tiny marine microorganisms(海洋微生物) called phytoplankton. Because of the way light reflects off the organisms, these phytoplankton create colourful patterns at the ocean surface. Ocean colour varies from green to blue, depending on the type and concentration of phytoplankton. Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance.

Phytoplankton live at the ocean surface, where they pull carbon dioxide(二氧化碳) into the ocean while giving off oxygen. When these organisms die, they bury carbon in the deep ocean, an important process that helps to regulate the global climate. But phytoplankton are vulnerable to the ocean’s warming trend. Warming changes key characteristics of the ocean and can affect phytoplankton growth, since they need not only sunlight and carbon dioxide to grow, but also nutrients.

Stephanie Dutkiewicz, a scientist in MIT’s Center for Global Change Science, built a climate model that projects changes to the oceans throughout the century. In a world that warms up by 3℃, it found that multiple changes to the colour of the oceans would occur. The model projects that currently blue areas with little phytoplankton could become even bluer. But in some waters, such as those of the Arctic, a warming will make conditions riper for phytoplankton, and these areas will turn greener. “Not only are the quantities of phytoplankton in the ocean changing. ” she said, “but the type of phytoplankton is changing.”

And why does that matter? Phytoplankton are the base of the food web. If certain kinds begin to disappear from the ocean, Dutkiewicz said, “it will change the type of fish that will be able to survive.” Those kinds of changes could affect the food chain.

Whatever colour changes the ocean experiences in the coming decades will probably be too gradual and unnoticeable, but they could mean significant changes. “It’ll be a while before we can statistically show that the changes are happening because of climate change,” Dutkiewicz said, “but the change in the colour of the ocean will be one of the early warning signals that we really have changed our planet.”

Wide, sandy beaches stretch nearly 20 miles along the Pacific Ocean. Between December and February, this surfing destination is suitable only for experienced surfers, as its big waves can reach 30 feet. In summer, the ocean can be almost completely flat, making it perfect for swimming.

This busy 8.5-mile-long beach attracts 8 million visitors a year for bodysurfing, boogie boarding （趴板冲浪）, and board surfing at every level, beginner to expert. At night, the beach’s fire pits （深坑） draw families as much as the waves do during the day. The best time for surfers is winter, when the swells can hit 15 feet.

This area of the ocean may contain the most consistent waves on the planet, with some up to 10 feet. The best waves are between late May and late August. The beach sometimes closes because of sharks, but at other times, surfers are lucky enough to surf alongside dolphins.

This beach has waves up to 12 feet high, which are good for long-boarders or short-boarders, beginners or experts, with the best waves from April to July. Bodysurfing is not recommended because of offshore rocks. The laid-back atmosphere and nearly perfect year-round weather make it feel like the California beaches of the 1950s.

10 . In late March of 2018.a tear in the earth about 15 meters wide and 20 meters deep suddenly appeared in Kenya, it cut across roads and even split houses in two. This crack appeared out of nowhere after heavy rains and an increase in seismic activity. Some scientists believe that it is further proof that Africa is slowly splitting apart.

Once a very long time ago, Africa and south America were one landmass before they separated. Similarly, one day in the very distant future, a large part of East Africa will split off from the rest of the continent. This will create a new landmarks and a new ocean. The breakup is the result of plate tectonics, the gradual motion of different parts of the Earth's crust.

When plates of the Earth separate and tear away from each other. It is called rifting. The result is rift valley. Scientists don't understand the exact mechanism behind rifting. But the result is very easy to observe in theEast African Rift System(EARS), That's why studying this part of the world is so important.

The East African Rift system begins in the north in Ethiopia, where three plates are moving away from each other. Two of them are continental plates, the African and Arabian plates. They are tectonic plates that have a large landmass above water. The third is the Somali plate, considered a minor plate, which is steadily moving away from the other two. But don't plan on visiting the new ocean anytime soon. The plates are moving at a rate of about 6 millimeters a year. At the speed millions of years will pass before a new ocean is formed.

EARS is not all bad news for Kenya. A rift valley is composed of an area where there is increased volcanic activity and thinned planetary crust. This makes it easier to take advantage of the power of steam. For Kenya, this might be an answer to the country's electrical problems. The drought conditions that frequently occur there make it difficult to produce energy. But the geothermal(地热的) power plants going online in 2019 will allow them to produce clean energy with very little water.