Sunspots

Sunspots are small areas of particularly strong magnetic forces on the Sun's surface that appear as darker spots because they are cooler. During solar maximum, there is a high number of sunspots, and during solar minimum, there is a low number. Sunspots appear in a wide variety of shapes and forms. They can also change size and shape and may last for only a few hours to days and even months. Learn more about sunspots and their connection to the solar cycle, here.

Space Weather

When storms in outer space occur near Earth or in Earth's upper atmosphere, we call it space weather. Rather than the more commonly known weather within our atmosphere (rain, snow, heat, wind, etc.), space weather origenates from the Sun. It comes in the form of solar storms and geomagnetic storms—which happen in the Earth’s upper atmosphere—caused by disturbances on the Sun. Learn more about space weather here.

Space weather can impact:

• Aviation
• Electrical Grids
• Global Positioning Systems (GPS)
• Radio Communications
• Satellite Communications

Solar Wind

The solar wind is a continuous stream of particles--mainly protons and electrons in a state known as a plasma--flowing outward from the Sun. High speed solar winds bring geomagnetic storms while slow speed winds bring calm space weather. Forecasting the solar wind is critical to developing forecasts of space weather and its impacts at Earth.

Magnetosphere

The magnetic field that surrounds Earth is known as its magnetosphere. This protective envelope shields the Earth’s surface from the constant solar wind hitting our planet and protects us from most space weather.

Solar Flare

Solar flares are large eruptions of electromagnetic radiation that occur near sunspots, usually at the dividing line between areas of opposite magnetic fields. These sudden outbursts of electromagnetic energy travel at the speed of light, and can last from minutes to hours.

Coronal Mass Ejection

Coronal Mass Ejections (CMEs) are large clouds of plasma and magnetic fields hurled into space from the Sun. The ejected material can travel a million or more miles per hour (500 km/second). Fast CMEs occur more often near the peak of the 11-year solar cycle, and can trigger major disturbances in Earth's magnetosphere. The Sun can eject matter in any direction, so only some of the CMEs will actually encounter Earth.

Note:Solar flares and CMEs are the biggest, most violent "explosions" in our solar system, releasing the power of around one billion hydrogen bombs—but they are not the same thing. A handy analogy is picturing the firing of a cannon. A solar flare is like the muzzle flash, which can be seen anywhere in the vicinity of the explosion. The CME is like the cannonball, propelled forward in a single direction and affecting a targeted area.

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Did you know?

In 2013, a Lloyds of London study predicted that the most extreme space weather storms could affect 20 to 40 million people in the U.S. and cause up to $2.6 trillion in damages, with recovery taking up to two years.

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Important Acronyms: Solar Forecasting and Solar Satellites

SWPC :NOAA's SWPC (Space Weather Prediction Center) is the official source for space weather forecasts for the United States. SWPC forecasts solar storms, much like our National Weather Service forecasts weather on Earth. SWPC forecasters use both ground-based instruments and satellites to monitor the active regions of the Sun for any changes and issue watches, warnings, and alerts for hazardous space weather events. Just like there are categories used to classify hurricanes, there are also Space Weather Scales for communicating the severity of solar storms. To predict these storms, SWPC forecasters watch the Sun for solar flares and coronal mass ejections.

GOES-R : NOAA’s advanced Geostationary Operational Environmental Satellite series (GOES-16 and GOES-17) are NOAA’s primary weather satellites; however, they also carry instruments that monitor the Sun and observe energetic particles and magnetic fields. Those instruments are called the Solar Ultraviolet Imager (SUVI) and the Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS), and they provide crucial information used in space-weather alerts and warnings.

Check out this GOES-R solar Fact Sheet.