Sunspots

Subject: Science and tech

Context:

A massive Sunspot group, AR2770, was observed last week, claimed using images of the Sun’s surface from NASA’s Solar Dynamics Observatory (SDO).

Concept:

• Sunspots are areas that appear dark on the surface of the Sun.
• They appear dark because they are cooler than other parts of the Sun’s surface.
• It’s cool because they form at areas where magnetic fields are particularly strong. These magnetic fields are so strong that they keep some of the heat within the Sun from reaching the surface.
• Most Sunspots appear in groups that have their own magnetic field, whose polarity reverses during every solar cycle, which takes around 11 years. In every such cycle, the number of Sunspots increases and decreases.

• The magnetic field lines near sunspots often tangle, cross, and reorganize. This can cause a sudden explosion of energy called a solar flare.
• Solar flares release a lot of radiation into space. If a solar flare is very intense, the radiation it releases can interfere with our radio communications here on Earth.
• Solar flares are sometimes accompanied by a coronal mass ejection (CME for short).
• CMEs are huge bubbles of radiation and particles from the Sun. They explode into space at very high speed when the Sun’s magnetic field lines suddenly reorganize.
• When charged particles from a CME reach areas near Earth, they can trigger intense lights in the sky, called auroras.
• When particularly strong, a CME can also interfere in power utility grids, which at their worst can cause electricity shortages and power outages. Solar flares and CMEs are the most powerful explosions in our solar system.