There have been claims that warming on Mars(火星) and Pluto(冥王星) is proof that the recent warming on Earth is caused by an increase in solar activity, and not by greenhouse gases. But we can say with certainty that, even if Mars, Pluto or any other planet has warmed in recent years, it is not due to changes in solar activity.

The Sun’s energy output has not increased since direct measurements began in 1978. If increased solar output really was responsible, we should be seeing warming on all the planets and their moons, not just Mars and Pluto.

    Our solar system has eight planets, three dwarf planets and quite a few moons with at least a thin atmosphere, and thus a climate of sorts. Their climates will be affected by local factors such as orbital variations, changes in reflectance and even volcanic eruptions, so it would not be surprising if several planets and moons turn out to be warming at any one time.

    One theory is that winds have recently swept some areas of Mars clean of dust, darkening the surface, warming the Red Planet and leading to further increases in windiness --- a positive feedback effect.

Observations of the thickness of Pluto’s atmosphere in 2002 suggested the dwarf planet was warming even as its orbit took it further from the Sun. The finding confused astronomers at the time, and the cause had yet to be determined.

It has since been suggested that this is due to a greenhouse effect: As it gets closer to the Sun, Pluto may warm enough for some of the methane ice on its surface to turn into a gas. This would cause further warming, which would continue for a while even after Pluto’s orbit starts to take it away from the Sun.

With its incredibly long neck, giraffe looks like no other animal on Earth. But how did this mammal come to get its famously huge neck? Well, scientists have been asking themselves this question for centuries.

The most commonly believed answer is that the massive neck – which measures on average 180 centimeters and weighs about 270 kilograms – evolved to allow the animal to reach the leaves of tall trees. British scientist Charles Darwin was one of the first people to propose this idea in the 1800s.

Yet, there are other theories.

According to a paper published in September in the Journal of Arid Environments, the giraffe’s neck evolved to increase its surface-area-to-volume ratio (表面积—体积比). Because the animal’s neck increases its body’s surface area, it makes it easier for it to keep cool, the paper’s authors wrote.

This phenomenon can be seen everywhere in nature. For example, this is why elephants have such large ears.

Meanwhile, some believe that competition is the answer.

A 1996 study by two South African zoologists argued that the male giraffes with the biggest necks are the ones who “win” access to females to reproduce, as they are better at fighting, meaning that their long necks are passed down through the generations.

So, it seems like there’s still no definite answer to the question.

Shoppers could soon use their mobile phones to check how ripe fruit and vegetables are with an “X－ray vision” camera.

    The HyperCam, based on hyper spectral (高光谱的)imaging, can assess ripeness with 94 percent accuracy and could also be used to check for rotting produce in the fridge at home. Scientists at the University of Washington in Seattle managed to create a portable hyper spectral imaging camera that would cost $ 800 (£520).

     Hyper spectral imaging uses a broader range of the electromagnetic spectrum(电磁波)than an ordinary camera. The researchers are now working on a version of the technology that shoppers could download on to a mobile phone for about $ 50. The technology is already used in satellite imaging, building safety inspection, but is a highly costly process.

    Professor Shwetak Patel, of the University of Washington, said: “It’s not there yet but you can probably imagine putting it in a mobile phone. With this kind of camera you could go to the grocery store and know what produce to pick by looking underneath the skin and seeing if there’s anything wrong inside. It’s like having a food safety app in your pocket.”

    Neel Joshi, a Microsoft researcher, said: “Existing systems are costly and hard to use so we decided to create an inexpensive hyper spectral camera and explore these uses ourselves. After building the camera we just started pointing it at everyday objects, really anything we could find in our homes and offices, and we were amazed at all the hidden information it revealed.”

    Other potential uses for the technology include analyzing blood vessels and identifying individual people by the unique texture (纹理) of their skin.

    When a leafy plant is under attack, it doesn't sit quietly. Back in 1953, two scientists, Jack Schultz and Ian Baldwin, reported that young maple trees getting bitten by insects send out a particular smell that neighboring plants can get. These chemicals come from the injured parts of the plant and seem to be an alarm. What the plants pump through the air is a mixture of chemicals known as volatile organic compounds, VOCs for short.

    Scientists have found that all kinds of plants give out VOCs when being attacked. It's a plant's way of crying out. But is anyone listening? Apparently. Because we can watch the neighbours react.

    Some plants pump out smelly chemicals to keep insects away. But others do double duty. They pump out perfumes designed to attract different insects who are natural enemies to the attackers. Once they arrive, the tables are turned. The attacker who was lunching now becomes lunch.

    In study after study, it appears that these chemical conversations help the neighbors. The damage is usually more serious on the first plant, but the neighbors, relatively speaking, stay safer because they heard the alarm and knew what to do.

    Does this mean that plants talk to each other? Scientists don't know. Maybe the first plant just made a cry of pain or was sending a message to its own branches, and so, in effect, was talking to itself. Perhaps the neighbors just happened to "overhear" the cry. So information was exchanged, but it wasn't a true, intentional back and forth.

    Charles Darwin, over 150 years ago, imagined a world far busier, noisier and more intimate(亲密的) than the world we can see and hear. Our senses are weak. There's a whole lot going on.

Do you know electricity can change the way we taste food? Proving this fact is a revolutionary electric fork designed by Japanese researchers that can make any dish taste salty.

According to Hiromi Nakamura, a Post Doc Research Fellow at Tokyo’s Meiji University, the technology can be very useful for people on special diets. Patients with high blood pressure, for instance, can easily go on a low-salt diet and still enjoy delicious food. And with the fork, there’s absolutely no risk of over-salting their food. Luckily, the voltage(电压) is so small that there is no risk of danger either.

The idea of adding electricity to food was first exposed as an experiment at the Computer Human Interaction Conference in Austin, Texas, in 2012. Nakamura and her team connected a wire to a 9-volt battery and passed it through a straw placed in a cup of sweet lemonade. Volunteers reported that the charged lemonade tasted ‘blander’, because the electricity created the taste of salt.

Nakamura has improved the technology to be able to transfer an electric charge to food through forks and chopsticks. “The metallic part of the fork is one electrode（电极）, and the handle is the other,” Nakamura explained. “When you take a piece of food with the fork and put it in your mouth, you connect the circuit. When you remove the fork from your mouth, you disconnect the circuit. So it actually works as a switch.”

Simon Klose, host of food program Munchies, who recently visited Nakamura to try out the fork himself, called this form of ‘food hacking’ one of the greatest eating experiences he’d ever had.

“When I first heard of electric food, it sounded scary,” he said. He later continued to use a charged fork to eat pieces of fried chicken, and found that the saltiness considerably increased as the electricity was connected.

Nakamura has been eating ‘electric’ food for the past three to four years in an attempt to understand it better. “For me, ‘food hacking’ is about strengthening or weakening real food,” she said. “It may seem like we’re cooking but we’re actually working on the human senses.”