Here's a breakdown:

* Solar flares are powerful bursts of energy from the Sun's surface. They release intense radiation, including X-rays and ultraviolet light, into space.

* Brightness increase: The radiation from a solar flare can cause a sudden, temporary increase in the Sun's brightness.

* Other effects: Solar flares can also disrupt radio communications, cause power outages, and even damage satellites.

It's important to note that a solar flare is distinct from a coronal mass ejection (CME), which is a much larger release of plasma and magnetic field from the Sun's corona. While both events can cause significant space weather effects, CMEs are usually slower and more sustained than solar flares.