Login With Google
Sunspots
Why is it in News?
- A massive Sunspot group, AR2770, was observed recently.
Details:
- Observation was done by ‘com’ using images of the Sun’s surface from NASA’s Solar Dynamics Observatory (SDO).
- Sunspots:
(1) A Sunspot is an area on the Sun that appears dark on the surface and is relatively cooler than surrounding parts.
(2) These spots are the visible markers of the Sun’s magnetic field.
(3) Size of Sunspots can be as large as 50,000 km in diameter.
(4) Photosphere is the outer surface of the Sun which radiates heat and light.
(5) On the Photosphere, Sunspots are the areas where the star’s magnetic field is the strongest.
(6) Most Sunspots appear in groups that have their own magnetic field, whose polarity reverses during every solar cycle, which takes around 11 years.
(7) In every such cycle, the number of Sunspots increases and decreases.
(8) The current solar cycle, which began in 2008, is in its ‘solar minimum’ phase, when the number of Sunspots and solar flares is at a routine low.
- Why Sunspots appear dark?
(1) Because Sunspots have high magnetic pressures, the atmospheric pressure in the surrounding photosphere reduces.
(2) It results in inhibiting the flow of hot gases from inside the Sun to the surface.
(3) Because they stop the convective flow of heat and light, Sunspots appear dark.
(4) Photosphere has a temperature of 5,800 degrees Kelvin. Sunspots temperatures are around 3,800 degrees Kelvin.
(5) Sunspots typically consist of a dark region called the ‘umbra’, which is surrounded by a lighter region called the ‘penumbra’.
.
- Solar Flares and Coronal Mass Ejections:
(1) When a Sunspot reaches up to 50,000 km in diameter, it may release a huge amount of energy that can lead to solar flares.
(2) The flares are caused by explosions that are triggered due to the twisting, crossing or reorganising of magnetic field lines near Sunspots.
(3) Sunspots also triggers Coronal Mass Ejections (CME).
(4) Coronal Mass Ejections (CME) are large bubbles of radiation and particles emitted by the Sun that explode into space at high speed.
(5) CMEs can trigger intense light in the sky on Earth, called auroras.
- Effects of solar flares:
(1) Solar flares can have a major effect on radio communications, Global Positioning Systems (GPS) connectivity, power grids, and satellites.