Sunspots

Sunspots are dark areas on the surface of the Sun, formed where the magnetic field is particularly strong, blocking heat from rising to the surface. While the temperature of the Sun may be 6,000° Celsius (about 11,000° F), sunspots are about 1,500° Celsius cooler. Sunspot activity may appear in 11-year cycles, and in some cases may be visible without the aid of telescopes.

Pictured: Images of a sunspot group captured by the Mt. Wilson Observatory on August 3, 5, 7 and 9, 1915.

Faculae

Although sunspots cause a decrease in irradiance (electromagnetic radiation), they're accompanied by bright white blotches called faculae that cause an overall increase in solar irradiance.

2002

This image taken on July 15, 2002 by the Swedish 1-m Solar Telescope (SST) on the Canary Island of La Palma shows dramatic details of the dark cores of a sunspot.

1947

On April 8, 1947 astronomers at Mt. Wilson Observatory witnessed the largest array of sunspots ever recorded. The group of sunspots in the southern latitudes of the Sun was large enough to be observed without a telescope.

2004

An August 19 2004 image of a solar flare erupting from a giant sunspot.

2005

A sunspot captured on Jan. 17, 2005, by ESA/NASA's Solar Heliospheric Observatory.

2008

This image provided by NASA's Solar and Heliospheric Observatory (SOHO) shows a new sunspot (upper right) which, after many weeks of a blank sun with no sunspots and very few sunspots this entire year, emerged on Sept. 23, 2008. 

2012

This still from a NASA video shows a Fourth of July solar flare from sunspot AR1515, as captured by NASA's Solar Dynamics Observatory on July 4, 2012.

2013

This image of sunspots from February 19-20, 2013 combines images from two instruments on NASA's Solar Dynamics Observatory (SDO): the Helioseismic and Magnetic Imager (HMI), which takes pictures in visible light that show sunspots; and the Advanced Imaging Assembly (AIA), which took an image in the 304 angstrom wavelength showing the lower atmosphere of the sun, which is colorized in red. 

2013

Sunspot AR1748 erupted with a medium-class M3.2 flare on May 17, 2013.

2014

A gigantic sunspot - nearly 80,000 miles across - can be seen on the sun in this image taken by NASA's Solar Dynamic Observatory on October 23, 2014. Ten Earths could be laid across its diameter.

2017

The August 21, 2017 total solar eclipse offered a unique perspective of the International Space Station - its silhouette barely visible along with a smattering of sunspots on the Sun's surface.