A once-tiny spot on the sun's surface grew over the weekend to the size of Earth, potentially threatening our planet with radio blackout-causing solar flares and plasma eruptions that could trigger aurora displays.
The sun has been lively in the past few weeks, treating skywatchers at high latitudes and astronauts onboard the International Space Station to beautiful aurora displays. There may be more of those storms to come, as the sunspot AR3085 keeps growing and rotating toward Earth.
The sunspot is one of six active regions currently observable on the disk of the sun, but space weather forecasters are not too worried about it, predicting low activity for the next 24 hours with occasional mild solar flares that could possibly cause short-duration radio blackouts, according to U.K. space weather forecaster Met Office (opens in new tab).
Met Office expects the low solar activity to continue in the next four days, with a small chance of an increase to moderate levels. A small coronal hole, an opening in the magnetic field lines in the sun's upper atmosphere, the corona, may increase the flow of solar wind toward Earth, possibly leading to turbulent geomagnetic conditions, which might make auroras visible farther away from the poles.
Of course, the sunspot AR3085, which has, according to spaceweather.com, increased in size tenfold in the past two days, might fire a coronal mass ejection (CME) — a burst of charged particles — at Earth, triggering a geomagnetic storm later in the week. Currently, however, no such CME is heading our direction.