The ancient game of go is played with black and white stones on a square wooden board checkered with 19 vertical lines and 19 horizontal ones to form 361 points of intersection. In turn, each player tries to conquer territory by completely enclosing vacant points with boundaries made of their own stones. The first player to do so gains control of the entire board. In the past, mastery of this absorbing and complex game was considered one of the marks of a cultivated scholar or gentleman; today it is considered a valuable intellectual activity for its own sake. However, the rise of AlphaGo may spell the end of human dominance in this noble art.

GOES stands for Geostationary Operational Environmental Satellites, a joint NOAA and NASA program that provides continuous imagery and data on atmospheric conditions and solar activity (space weather) for 40 years. GOES provides critical information to NOAA National Weather Service forecast offices and centers, volcanic ash advisory centers, and other government agencies and the public.

Operational GOES satellites reside in geostationary orbit 35,790 kilometres (22,240 miles) above Earth. Each satellite is equipped with two primary sensors: the Imager and Sounder. The Imager senses infrared radiation and visible light reflected from clouds and the surface of the Earth, while the Sounder detects vertical atmospheric temperature and water vapour structures. Using flexible scan controls, the Imager and Sounder can rapidly zoom in to monitor individual regions of interest and also continuously image the Earth at a high temporal cadence of 10 minutes for global scenes (Earth’s full disk).

Each GOES satellite is controlled from the NOAA Satellite Operations Center in Suitland, Maryland. During severe weather events, the regular schedule of scans can be altered to provide additional observations and more frequent data to meteorologists on the ground.

Both the GOES-East and GOES-West satellites have a wide area of coverage that includes North America, most of the Atlantic Ocean and the Pacific Ocean. Each satellite has three-axis body stabilisation, allowing the instruments to “stare” at the Earth, providing real-time observations of the evolution of meteorological phenomena such as severe local storms and tropical cyclones.

There are several types of GOES sensor stations that collect weather data from the atmosphere:

1) Self-timed DCPs. – These have a pre-programmed transmitter and timer that enables the sensor to report at regular intervals to GOES. They are the most common type of GOES sensor station.

2) Random reporting DCPs. – These have the same functionality as 1) but can report at random over a secondary channel when environmental conditions reach a trigger point.

3) Interrogated DCPs. – These send a message through the DCP identification system at the satellite to the satellite control center requesting data from the station. 4) Other sensors. – These sensors gather data for other purposes such as seismic monitoring and ocean tide gauges.

The Geostationary Operational Environmental Satellites are part of the NOAA Polar Orbiting Environmental Satellites (POES) fleet, which consists of 14 satellites with a combined life span of more than 50 years. The next GOES satellite is scheduled to launch in 2024.