The destructive power of the gorgeous solar flare in the image on the left is unfathomable. A single solar flare releases millions of megaton hydrogen bombs worth of energy.
These phenomena are so powerful that they can even affect us here on Earth. They can't harm us directly, thanks to our protective atmosphere, but they can cause events known as radio blackouts.
This most recent solar flare occurred on June 25. By definition, solar flares are intense variations in the sun's brightness that occur quickly and suddenly. They happen when magnetic energy builds up in the sun's atmosphere and then gets released all at once. This causes an enormous explosion of radiation of nearly all varieties, from radio waves to gamma rays.
Within that range are X-rays and extreme ultraviolet rays. When these kinds of radiation hit the Earth's atmosphere, they trigger a chemical reaction that changes its reflective properties on the sun-facing side of the planet. This is important because we depend on certain parts of the atmosphere to reflect the radio waves we use for long-distance communication, including those used for GPS, when there is no clear "line-of-sight" between the transmitter and receiver of a signal.
If a solar flare is strong enough, it can change the properties of some of the molecules in the atmosphere such that they absorb the radio waves instead of reflecting them. So, any radio waves that get caught in this crossfire from the sun aren't just delayed — they disappear entirely.
The latest major solar flare was mid-size, or M-class, according to NASA's Solar Dynamics Observatory. The scale goes A, B, C, M and then, finally, X, for the most intense solar flares. These categories also indicate the frequency of radio waves that the flare can disrupt.
A disclaimer: you should never look directly at the sun without proper eye protection anyway, but you definitely shouldn't stare at the sun in the hopes of catching a solar flare. As big and bright and powerful as they are, they're not visible with the naked eye. However, there are a whole bunch of incredible images of solar flares from NASA's Solar Dynamics Observatory.