The bicycle is a popular mode of transportation in many parts of the world. It is lightweight, economical and environmentally friendly. It can be used by people of all ages and abilities. It is a safe form of transportation, as long as the rider follows basic rules and uses proper safety gear.

Bicycles may have coaster brakes or hand brakes. When a person pedals backward on a bicycle with coaster brakes, pads squeeze against the wheels and the bike stops. Hand brakes are controlled by levers on the handlebars. When the rider squeezes the levers, pads are forced against the wheels and the bike stops. Bicycles also have gears, which are sets of freewheel sprockets that allow the rider to select different pedaling speeds. For example, higher gears make pedaling easier and let the bicycle travel faster, while lower ones require more effort to ride but allow the bike to go slower.

Historians have many claims about the origin of the bicycle. Some believe Leonardo da Vinci drew a diagram of the bicycle in his Codex Atlanticus in 1492. But there is no proof that this sketch was a genuine invention of the bicycle. The earliest verifiable claim of bicycle invention belongs to Karl von Drais. His Laufmaschine of 1817, or draisine, was the first practical human-powered two-wheeled vehicle that could be steered and powered by humans. The draisine was known by other names, including hobby horse, dandy horse and the 19th-century term penny farthing.

After the draisine came the pneumatic tire and the chain drive, which revolutionized bicycles in the later 1800s. James Starley in Coventry added the tangent spokes and the mounting step, and other manufacturers produced bicycles with hollow-section steel frames that were lighter and stronger than those made of cast iron or wood. The new bicycles were safer as well, because the rider sat almost directly over the front wheel and was less likely to be pitched forward by road hazards or severe braking.

Today, bicycles can be made from a wide variety of materials, including carbon fiber, titanium and aluminum. Some are designed to be extremely lightweight, while others are built for rugged use in off-road terrain. Despite the many changes in design, basic bicycles remain almost the same, and most still have a frame with two wheels, pedals, handlebars and a seat.

The most recent bicycle technology has involved improvements in suspension, frame design and components. These innovations have allowed for the development of bikes that are more comfortable and efficient to ride. Many of these new models have become popular among racing cyclists.

Regardless of the type of bicycle you choose, it is important to wear a helmet and to use proper safety equipment. A helmet is especially critical for children riding bikes. It is also a good idea to wear bright clothing, so other road users can see you. Remember that all states require bicycles to follow the same traffic laws as motorists, so obey all traffic signals and signs. It is also wise to ride only one bike at a time and to keep both hands on the handlebars, unless signaling a turn.

The GOES satellites continuously observe the Earth’s surface and atmosphere by detecting electromagnetic radiation. These data are transmitted to Earth and used to create images that reveal conditions in the atmosphere.

The images that GOES generates show many types of phenomena, from thunderstorms forming over East Texas to a fireball streaking through the skies over New Mexico to the spread of wildfires across the southwest. They also reveal the effects of a changing climate.

GOES satellites circle the Earth in geosynchronous orbit, which means that they are positioned over the same spot on the planet at all times, like an airplane flying in the sky above you. This allows the sensors to stare at a specific area of the Earth all day and night, allowing meteorologists to constantly monitor the Earth’s surface and atmosphere.

A GOES satellite’s sensors collect two kinds of electromagnetic radiation. One type, called thermal infrared (IR), is emitted from the ground and the lower parts of clouds. The satellites’ instruments measure the amount of this IR radiation being emitted, enabling scientists to determine temperature and water vapor content at those levels. The longer wavelengths of thermal infrared radiation are absorbed by oxygen, carbon dioxide, ozone, and water vapor in the Earth’s atmosphere; only the shorter wavelengths pass through.

The other kind of radiation detected by GOES is radio waves, which are emitted from the Sun and its flares. Those waves are measured by GOES’s Solar and Heliospheric Imager (SXI), which alerts NOAA/SEC to any potentially hazardous solar activity that may affect spaceborne or ground-based assets, including power lines.

In addition to the SXI, all GOES satellites are equipped with the Advanced Baseline Imager (ABI) and the Solar Wind Energy Sensor (SWES). ABI is a state-of-the-art 16-band radiometer that provides excellent spatial, temporal, and radiometric resolution for visible, near-infrared, and infrared imagery of the Earth at both surface and cloud levels. The ABI instrument has significantly improved spectral, spatial, and radiometric performance as compared to the older GOES series.

The CLASS system hosts NOAA GOES satellite and derived products, including images displayed in the GOES Image Viewer, on the Internet for anyone to access. However, the data and images hosted on CLASS webservers and in the GOES Image Viewer are NOT official NOAA operational products; they are examples of ongoing experimental product development.