I Am Not a Robot

An annoyance, an important security feature, an uncomfortable request: however you feel about being asked to prove you are not a robot, it has become a daily occurrence for most of us, but perhaps not one we would miss if it were to suddenly go away.

A new feature in the latest versions of iOS and macOS, Apple’s operating systems for smartphones and computers, promises to give the boot to “captchas” once and for all. 【小题1】

“Sometimes a captcha is just a button to press,” said Apple engineer Tommy Pauly. “But other times it can be a challenge to fill out.”

The term captcha is in fact an acronym (首字母缩略词) for   “completely automated public Turing test (图灵测试) to tell computers and humans apart.” To help stop fraud (欺诈), these little tests often pop up when you’re signing up for or onto a website.

【小题2】 If you get it wrong, it may ask you to start again, leading you to wonder if you really know what a traffic light looks like—or if you might really be a robot after all.

But captchas are now fast becoming unusable, making the Internet a wasteland of difficult puzzles. Users must struggle to do the most basic things. “We’ve literally all found ourselves at one time or another complaining: ‘Those were all the pictures with traffic lights,” said Effie Le Moignan, a researcher in social computing at Newcastle University.

Internet users struggle to tell the difference between a wear of paint on a sidewalk and a formalized crosswalk that’s often requested in a traditional captcha, and worry that one wrong answer may lock them out of an account. 【小题3】

“You likely don’t enjoy being interrupted by these,” said Apple’s Tommy Pauly. “I certainly don’t. The reason these experiences exist is to prevent dishonest activity. If you run a server, you don’t want it to be defeated by fraud. 【小题4】”

The company worked with Fastly and Cloudflare to build the new feature. It works by allowing your device to send a statement confirming it is being used by a human to the requesting website.

Searching Venus’ sky

From the moon to Mars, scientists have been hunting for alien life in the solar system for decades.

However, Venus was not regarded as an ideal place because of its hot temperature and dry atmosphere.

But a recent discovery of traces of a gas in the clouds of Venus has excited astronomers, as it may serve as a potential sign of life.

On Sept 14, the Royal Astronomical Society of Canada announced that scientists have detected phosphine(磷化氢) in the clouds of Venus. Phosphine is a colorless, toxic(有毒的)gas that has an odor of garlic. Though toxic, it is viewed as a possible sign of life because on Earth the gas is made by microorganisms that live in oxygen-free environments.

“I was very surprised - stunned, in fact,” astronomer Jane Greaves of Cardiff University in Wales and lead author of the research, told MSN. “There is a chance that we have detected some kind of living organism in the clouds of Venus.”

This layer of clouds is about 48 kilometers above the Venus surface, with its temperature ranging from 30 to 200 degrees Fahrenheit (about -1 to 93℃). Scientists have speculated that if life exists on Venus, this cloud deck(云盖)is likely the only place where it would survive.

Scientists went through every possibility that could have led to the formation of phosphine gas in Venus’ clouds, including volcanoes, lightning strikes, small meteorites(陨石)falling into the atmosphere. But they ruled all of them out. It was concluded that there is no explanation for the existence of this gas in Venus’ clouds, other than the presence of life, USA Today reported.

Although the detection of phosphine is not robust(强有力的)evidence for life, this finding is great enough to change scientists’ view on Venus, which is thought to be a completely inhospitable planet.

What signs of life we looking for?

1. Liquid water: It can dissolve a huge range of molecules needed for life and facilitate their chemical reactions.

2. Mild temperatures: Temperatures higher than 122 C will destroy most complex organic molecules, and make it almost impossible for carbon-based life to form.

Learning a second language is tricky at any age (and it only gets tougher the longer you wait to open that dusty French book). Now, in a new study, scientists have pinpointed the exact age at which your chances of reading fluency in a second language seems to plummet: 10.

The study, published in the journal Cognition, found that it’s “nearly impossible” for language learners to reach native - level fluency if they start learning a second tongue after 10. But that doesn’t seem to be because language skills go downhill. “It turns out you’re still learning fast. It’s just that you run out of time, because your ability to learn starts dropping at around 17 or 18 years old,” says study co-author Joshua Hartshorne, an assistant professor of psychology at Boston College.

Kids may be better than adults at learning new languages for many reasons. Children’s brains are more plastic than those of adults, meaning they’re better able to adapt and respond to new information. “All learning involves the brain changing,” Hartshorne says, “and children’s brains seem to be a lot more skilled at changing.”

Kids may also be more willing to try new things (and to potentially look foolish in the process) than adults are. Their comparatively new grasp on their native tongue may also be advantageous. Unlike adults, who tend to default（默认）to the rules and patterns of their first language, kids may be able to approach a new one with a blank slate（石板）.

These findings may seems discouraging, but it was heartening for scientists to learn that the critical period for fluent language acquisition might be longer than they previously thought. Some scientists believed that the brief window closes shortly after birth, while others stretched it only to early adolescence. Compared to those estimates, 17 or 18 -- when language learning ability starts to drop off -- seems relatively old. “People fared better when they learned by immersion（沉浸）, rather than simply in a classroom. And moving to a place where our desired language is spoken is the best way to learn as an adult. If that’s not an option, you can mimic   an   immersive   environment   by   finding   ways   to   have   conversations   with   native   speakers   in   their own communities,” Hartshorne says. By doing so, it’s possible to become conversationally proficient -- even without the advantage of a child’s brain.