For the last month, a married couple has been interacting with a robot — called an Avatar — （hat’s con trolled by their daughter hundreds of miles away. Made by ANA Holdings Inc, it looks like a vacuum cleaner with an iPad attached. But the screen displays the daughter’s face as they chat, and its wheels let her walk slowly about the house as though she’s really there.

“Virtual travel” is nothing new, of course. Storytellers, travel writers and artists have been stimulating the senses of armchair tourists for centuries. It’s only in recent decades that frequent, safe travel has become available to the non-wealthy.

Yet even as the world’s middle classes climb out of the armchair and into economy-class seats, there are signs of a post-travel society appearing. Concerns about the environment make people lose interest in carbon-intensive (碳排放量很高的) airlines. And the aging of societies is both slowing down the growth of physical travel and creating demand for alternative ways to experience the world. For the travel industry, virtual reality offers a tantalizing (诱人的) response to these trends.

Of course, far-out (前卫的) technologies encourage profits. ANA doesn’t plan to start selling Avatars until next year. By one estimate, the global market for this kind of technology will be worth only about S300 million by 2023. By contrast, ANA’s traditional travel business brought in more than $19 billion last year.

But although the business case for virtual vacations is still weak, the market for technologies that bridge physical distances between families and coworkers seems likely to only expand. ANA’s robots may not replace its airplanes any time soon, but they’ll almost certainly be a part of travel’s high-tech future.

Later this month, Tate Britain will host its first Van Gogh exhibition since 1947. Here we’ve collected 4 of his best paintings before the show.

Potato Eaters

Potato Eaters was Van Gogh’s first major work and, despite a distinct lack of colour, it was one that he was most proud of. His aim was to represent the difficulties of country life, so the farmers are painted in earthy tones with rough faces and bony hands. He was more concerned with conveying his message than achieving technical perfection in this painting.

Irises

Van Gogh finished almost 142 pieces during his stay in the Saint Remy de Provence asylum (精神病院), where he was a voluntary patient from 1889 to 1890. This piece was started shortly after he arrived there. The hospital garden provided much inspiration for the artist during his stay there. Originally, the flowers in this work were painted purple but the red pigment (色素) faded over time and has now turned blue.

Cafe Terrace at Night

Despite being painted more than 130 years ago, this cafe still exists in France and has since been renamed the Cafe Van Gogh. This artwork marks the first time Van Gogh’s famous post-impressionistic star-filled sky was seen in a piece, and it was painted on the ground, in person, rather than from memory. While the artwork doesn’t bear his signature (签名), it’s widely known to be Van Gogh’s, as he mentioned Cafe Terrace at Night in a number of his letters.

Wheat Field With Cypresses

This piece was inspired by the view from Van Gogh’s asylum window and was finished on the spot. The work was the title of three paintings that offer an insight into his stay at the hospital. Van Gogh was so pleased with the summer landscape that he made three copies there, one of the same size — which hangs in the National Gallery and two smaller copies which he planned to gift to his mother and sister.

India and China are leading the global greening effort, a latest NASA study said on Monday, observing that the world is a greener place than it was 20 years ago.

Data from NASA Earth satellites show that human activities in China and India play an important part in this greening of the planet, thanks to tree planting and agriculture. The effect comes mostly from tree-planting programs in China and agriculture in both countries. “China and India account for one-third of the greening,’’ said lead author Chi Chen of Boston University.

China alone accounts for 25 percent of the global increase in leaf area with only 6.6 percent of global green area. The greening in China is from forests and croplands (农田), but in India, it is mostly from croplands with minor contribution from forests. China’s huge contribution to the global greening trend comes in large part from its programs to protect and expand forests.

“When the greening of the earth was first observed, we thought it was due to a warmer, wetter climate from the added carbon dioxide (CO₂) in the atmosphere. Now with the data, we see that humans are also contributing,” said Rama Nemani, research scientist at NASA. “Once people realize there is a problem, they tend to fix it. In the 1970s and 80s in India and China, the situation around vegetation (植被) loss was not good. In the 1990s, people realized it, and today things have improved. That’s what we see in the satellite data,” added Nemani.

Land area used to grow crops is comparable in China and India, and has not changed much since the early 2000s. Yet these places have greatly increased both their green leaf area and their food production by enhancing the way of cropping. This was achieved through multiple cropping practices, where a field is replanted to produce another harvest several times a year. Production of grains, vegetables, fruits and more has increased by about 35%〜40% since 2000 to feed their large populations.