Telecom

Scientists improve smart phone battery life by up to 60 percent

Computer scientists from Aston University have developed a way to drastically improve the battery-life of mobile devices, such as smart phones and tablets, by minimising the power consumption of mobile apps by as much as ...

Security

Shortened URLs may open a window on your life

It may be convenient to shrink a long, convoluted web address into just a few characters that will fit into a tweet, but the trend of using shortened URLs offers a new opportunity for hackers to invade your privacy, Cornell ...

Security

Study finds 'lurking malice' in cloud hosting services

A study of 20 major cloud hosting services has found that as many as 10 percent of the repositories hosted by them had been compromised - with several hundred of the "buckets" actively providing malware. Such bad content ...

Robotics

Algorithm quickly finds hidden objects in dense point clouds

A new MIT-developed technique enables robots to quickly identify objects hidden in a three-dimensional cloud of data, reminiscent of how some people can make sense of a densely patterned "Magic Eye" image if they observe ...

Engineering

Mapping the indoors with lidar for public safety use cases

Scenario: you're driving to your new job at a university campus and using your Global Positioning System (GPS)-enabled smartphone to tell you—and your car—how to get there. Once you arrive, you begin using building signs ...

page 1 from 19

Cloud

A cloud is a visible mass of droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. A cloud is also a visible mass attracted by gravity, such as masses of material in space called interstellar clouds and nebulae. Clouds are studied in the nephology or cloud physics branch of meteorology.

On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths. They thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the gases, hence the gray or even sometimes dark appearance at the base. Thin clouds may appear to have acquired the color of their environment or background and clouds illuminated by non-white light, such as during sunrise or sunset, may appear colored accordingly. In the near-infrared range, clouds look darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths.

This text uses material from Wikipedia, licensed under CC BY-SA