Solar flares erupted from the surface of the Sun last June 10, heading in the direction of Earth. These flares will be harmless to life on Earth as they graze the planet, but the display of this pair of outbursts from our stellar companion was a rare treat for astronomers.
Astronomers classify flares by how much energy is released in their display. The most extreme of these events are noted as type X. After that, a number represents fractions of a grade. For instance, an X2 event is twice as powerful as an X1, and X3 is three times as powerful.
The first flare, an X2.2-class eruption, was seen at 7:42 EDT. The second event happened less than an hour later, at 8:36 EDT, and was classified as a X1.5 flare.
The dynamic pairing of solar events were witnessed by NASA's Solar Dynamics Observatory, launched in 2010. This observatory monitors the entire surface of the sun it can see 24 hours a day.
"Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground. However, when intense enough, they can disturb the atmosphere in the layer where GPS and communications signals travel," Karen Fox of the Goddard Space Flight Center said.
If either of the flares were to hit Earth directly, they could disrupt sate little and ground communications for up to an hour, NASA experts estimate. A warning of possible disruptions has been issued.
"Short lived impacts to [high frequency] communications should be expected. The flare was short lived in duration and initial analysis does not favor an additional associated coronal mass ejection (CME)," the Space Weather prediction center, wrote in a statement.
A coronal mass ejection is a massive eruption of material from the surface of our sun, often preceded by flares. Such severe outbursts could pose a significant hazard for space travelers, especially on long-endurance flights, like a future trip to Mars.
Each of the flares came from the same area of the sun, known as region 2087. Our stellar companion is currently in the most active time in its 11-year sunspot cycle. Astronomers denote the current round as Cycle 24.
This close encounter with solar flares could induce vivid northern and southern lights. These may be seen without the aid of a telescope or binoculars, from any area with a clear sky, and a good view toward the pole. The effect of the solar eruptions on the atmosphere and electronics is difficult to predict.
