Researchers finally cracked the mystery of "theta aurora," a stunning natural light show that takes place in the night sky and occurs at high latitudes.

This type of aurora, otherwise known as the Northern or Southern lights, is so-called because the aurora looks like the Greek letter Θ (theta), or an oval with a line through the center, when seen from above.

Like Us on Facebook

University of Southampton researchers said theta auroras are caused by solar winds hitting the Earth's atmosphere. These electrically charged atomic particles interact with the Earth's magnetic field, causing the shimmering displays.

To solve the mystery, researchers had a look at the particles in two "lobe" regions of the magnetosphere. While in normal circumstances the lobe is cold, recent observations and a look at past records suggest unusually hot lobe plasma was somehow linked to theta auroras.

The team checked the data and images from the IMAGE satellite and ESA's Cluster Satellite. Data revealed uncharacteristically energetic plasma in the lobe.

"Previously it was unclear whether this hot plasma was a result of direct solar wind entry through the lobes of the magnetosphere, or if the plasma is somehow related to the plasma sheet on the night side of Earth. One idea is that the process of magnetic reconnection on the night side of Earth causes a build-up of 'trapped' hot plasma in the higher latitude lobes," said lead author Robert Fear from the University of Southampton.

They have found out that energetic plasma signatures appear on high-latitude magnetic field lines that have been 'closed' by the process of magnetic reconnection and makes the plasma relatively hot, according to Fear.

The new findings appeared in a recent edition of the journal, Science.

TagsTheta Aurora, Northern Lights, Southern lights, high latitudes Earth, night time, plasma, solar winds