A bicycle is a human-powered, two-wheeled vehicle that can be used for transportation, recreation, or sport. More than 2 billion bicycles are currently in use worldwide, outselling automobiles by a factor of three to one. Bicycles are the most efficient means of human-powered travel, converting about 99% of the energy applied to the pedals into forward motion.

The bicycle is also an excellent fitness machine, providing a low-impact and full-body workout. A 30 minute bike ride burns over 100 calories and builds leg strength, while increasing cardiovascular endurance and aerobic capacity. Unlike some other sports, cycling can be easily adapted to any age or physical condition and can be performed at as low or as high intensity as desired.

Bicycles are generally made of steel or aluminum alloy for strength and light weight, with carbon fiber being used in higher-end models. Frames are often painted or powder coated to protect the finish. There are many accessories available for bicycles, including racks, fenders, lights, mirrors, reflectors, bottle cages, baskets, and bags. In some places, laws require bicycles to be equipped with certain safety devices.

A wide range of tires are available for bicycles, enabling them to be used on many different types of roads and terrain. Some bicycles have disk brakes, which provide more stopping power than rim brakes. Some bicycles have front and rear derailleurs, which allow the rider to shift gears without removing their hands from the handlebars. In addition to standard tires, there are specialized tires for off-road and racing use.

Many cities have bike lanes or paths that separate cyclists from motor vehicles. Increasingly, people are using bicycles for transport to work or school. In urban areas, bikes outnumber cars by more than two to one. Bicycles are also widely used for recreation, as they can be enjoyed in many types of weather and at any time of the day or night.

The invention of the bicycle revolutionized human mobility. It changed the way that people live, work and play, especially in developing countries. Today, the bicycle is the primary mode of transport for millions of people around the world. Its efficiency and convenience make it a popular form of transportation. The bicycle also has a significant environmental impact, reducing air pollution and traffic congestion in cities.

Cycling is a fun and healthy activity for people of all ages and abilities. In the United States, more than 60 million people ride a bicycle regularly. Most are primarily recreational riders, although there are also significant numbers of commuters and athletes.

When riding a bike on the road, be aware of your surroundings and follow all the rules of the road. Yield to other vehicles and pedestrians, and always check behind you before turning. Always wear a helmet, brightly colored clothing or reflective gear, and a reflector on your bicycle at night or in poor visibility. Also, make sure your bicycle fits you and is in good working order before riding it.

The GOES (Geostationary Operational Environmental Satellite) system of geosynchronous equatorial weather satellites has been a basic element of U.S. weather monitoring and forecasting since 1974. It is jointly funded and operated by NASA and NOAA. The GOES satellites are used by the National Weather Service to monitor atmospheric conditions throughout the United States and to provide severe storm tracking and meteorology research data.

A NOAA press release explains that the next generation GOES satellites, called the GOES-R series, will have sensors that will increase imagery resolution and allow for the detection of more detail in the atmosphere. In addition, it will have a new solar-pointing instrument and the first Geostationary Lightning Mapper to detect and monitor total lightning activity with a spatial resolution of 8 km across most of the Western Hemisphere.

This satellite will also include the first GOES Sounder to monitor vertical atmospheric temperature and moisture profiles and ozone distribution. All of the GOES-R series satellites will be the first to broadcast all of their data via direct broadcast, and it is expected that this will lead to more accurate and timely weather forecasts and more detailed information about long-term climate changes.

GOES-R will use the Advanced Baseline Imager (ABI) to provide improved Earth-viewing images. The ABI uses silicon (Si) for the visible and near-infrared spectral bands and mercury cadmium telluride for the infrared spectral band. The ABI images will have a spatial resolution of 1 km for the visible and 4 km for the infrared. The ABI coverage rate will be enhanced by a factor of five from the current GOES satellites, allowing a doubling of imaging capabilities.

In a recent paper, University of Washington researchers led by Professor Michael Hashimoto, analyzed GOES-R ABI imagery from a year-long study of Amazon seasonality to learn more about how the rainforest cycles water and carbon. He and his colleagues found that the GOES-R ABI observations show how seasonality varies throughout the Amazon basin due to a variety of factors, including weather. Previously, studies of Amazon seasonality have relied on polar-orbiting satellites that fly over the region just once or twice per day. GOES-R, with its persistent observations from geostationary orbit, will help improve global models that include Amazon seasonality.

The GOES-R series of satellites is a collaboration between NOAA and NASA. NOAA will fund the development and launch of the satellites, and NASA will design and build the sensor suite. The GOES-R series is scheduled to be launched through 2036, with one operational satellite in each of the eastern and western polar observing positions and an on-orbit spare. Prior to launch, each satellite is designated by a letter that will be changed to a number upon reaching its geostationary orbit. For example, GOES-U was renamed GOES-16 after launch. The process of testing a GOES satellite can take nearly a year. One test involves thermal vacuum testing, which involves placing the satellite in a chamber that has temperatures that range from 188 degrees Fahrenheit to minus 67 Fahrenheit to simulate the extremes encountered during launch and in the space environment.