A powerful geomagnetic storm that apparently originated from a rather unusual source hit our planet last weekend.
According to spaceweather.com, this surprise G1-class storm fell upon Earth around midnight (UT) on 25 to 26 June, opening a “crack in our planet’s magnetosphere”, with the solar winds that got into the crack producing a spectacular “display of auroras”.
"Wow, talk about surprises!" Harlan Thomas, a photographer from Calgary, Alberta, said as quoted by the website. "I went out before sunrise to shoot Comet C/2017 K2 (PanSTARRS) and the Moon-Venus conjunction when the auroras appeared. The display lasted all of five minutes, and what a five-minute show it was as the aurora became a naked eye with beautiful pillars."
Rather than being a product of a coronal mass ejection, this geomagnetic storm was apparently caused by a co-rotating interaction region, a transition zone between “slow- and fast-moving streams of solar wind”.
Live Science also points out that the storm coincided with the peak of a rare planetary alignment where Mercury, Venus, Mars, Jupiter and Saturn “lined up in the sky in order of their proximity to the Sun”, the first such alignment since 1864.