Solar flare

Solar flares were bursts of energy given off by active stars at periodic or random intervals. Solar flares contained gamma radiation which could be used as a power source and could devastate entire planets.

Historical significance
The greatest solar flare for a thousand years hit the Earth in 1930 and, attracted by dalekanium, struck the Empire State Building in the form of a lightning strike and was used by the Cult of Skaro to create human-Daleks. Martha Jones and Laszlo were also able to channel its energy to kill the pig slaves. (TV: Evolution of the Daleks)

Earth was saved from a massive solar flare capable of wiping out all life on the planet in the early 21st century by a global forest which grew in a day. (TV: In the Forest of the Night)

The Ghosties were forced to leave their home planet when it became threatened by solar flares. They created a fleet of spaceships, one of which landed in Cardiff in the 21st century. (AUDIO: Asylum)

On 21 November 2059, a solar flare caused Bowie Base One on Mars to lose contact with Mission Control on Earth for over ten hours during which time The Flood infected the base. As a result, in the original timeline, Earth remained unaware of what happened to Bowie Base One. (TV: The Waters of Mars)

The Seventh Doctor once tricked Sutekh into thinking he'd destroyed Earth by drawing him into the 29th century, a time where the planet had already been devastated by solar flares. After the ordeal, Isis stayed in this time period to help revitalise Earth into a home for humanity once more. (AUDIO: The Tears of Isis)

The Eleventh Doctor claimed that the threat of solar flares roasting the Earth caused the people of the United Kingdom to depart for a new home on the Starship UK around the 29th or 30th century. (TV: The Beast Below)

According to one account, in 51st century Earth was ravaged by solar flares and the rich left the planet in a fleet of space arks. (COMIC: The Keep)

Cousin Ceol timed her "resurrection" as Sojourner Hooper so that all traces would be destroyed by a solar flare. She only escaped the posthuman colony planet on the last refugee ship. (PROSE: Weapons Grade Snake Oil)

In 6087, human scientists predicted that due to solar flare activity the Earth would be uninhabitable for 5000 years, and froze a group of carefully selected humans in an "Ark" in space to repopulate the Earth after the climate had repaired itself. The rest of the humans were evacuated to Thermic shelters but were apparently not expected to survive through the entire period. (TV: The Ark in Space)

In 200,000, solar flare activity was reported by news channels aboard Satellite Five; solar flare activity had increased across space lanes "556" and so all commercial flights were cautioned. (TV: The Long Game) In 200,100, the Controller of the Game Station exploited a cycle of solar flares, which occurred every eleven years, to warn the Ninth Doctor and his allies about her "masters", the Daleks. During this time, the Daleks could not monitor her. (TV: Bad Wolf)

By 500,002 Earth had again been deserted due to solar flare activity. (AUDIO: The Girl Who Never Was)

Circa 2,000,000 AD, the Time Lords transported the entire solar system using a magnetron, devastating Earth. Less-informed people attributed the devastation to solar flares. (TV: The Mysterious Planet)

Some time prior to 10,000,000 AD, intense solar flares caused the Refusians of Refusis II to lose their physical forms. (TV: The Ark)

The homeworld of the Panjistri was destroyed by solar flares. (PROSE: Timewyrm: Apocalypse)

Alternate timelines
In River Song's World, there were reports of solar flares and sunspot activity causing interference across all radio signals. (TV: The Wedding of River Song) Éruption solaire