Sun is Loosing its Shine | UPSC

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Sun is Loosing its Shine | UPSC

Sun is Loosing its Shine | UPSC

      HEADLINES:

Cold comfort: The sun is cooling.

      WHY IN NEWS:

Does it mean there’ll be no global warming ?

SYLLABUS COVERED: GS 3 : Science and Technology

      LEARNING: 

For PRELIMS go through important definitions of Grand solar minimum , solar irradiance etc.

For MAINS can you describe Sun’s atmosphere with a neat diagram . This article will help you with it . Let us dive in !

      ISSUE: 

Scientists believe the Sun was at its weakest in 2019 in the last 100 years or so. #solar minimum.

STUDIES BY

United States National Oceanic and Atmospheric Administration’s (NOAA) Space Environment Centre.

MODERN GRAND SOLAR MINIMUM

The sun is going through a period of decreased activity known as the modern grand solar minimum.

  • The last time such an event occurred led to the Little Ice Age
  • A new 11-year-cycle of the Sun has begun.
  • This year 2020 marks the beginning of the 25th cycle.

SOLAR ACTIVITIES

  • The odd thing is that solar activity, measured by the number of Sun spots at any given time, is pretty low even in 2020.

SUN SPOT

Sun spots are areas of strong magnetic forces on the surface of the Sun  

  • Sometimes they are large as planets — that appear as darker spots because they are cooler.
  • The Sun had no Sun spots for around 71 per cent in 2020 through September 21, 2020, compared to 77 per cent in 2019.
  • In May this year, it was as high as 78 per cent, sparking fears of a Little Ice Age.
  • Scientists say the Sun may be going through a long period of decreased activity –Modern Grand Solar Minimum from 2020 to 2053.

WHAT IS LITTLE ICE AGE

  • The last time such an event occurred was during the Maunder Minimum — from 1645 AD to 1710 AD.
  • It was part of what is now known as the Little Ice Age .

The Earth went through a series of elongated cold periods during the medieval centuries. 

  • The surface temperatures on Earth will go down noticeably during the Modern Grand Solar Minimum due to a 70 per cent reduction in solar magnetic activity.

SOLAR IRRADIANCE

  • The complex magnetic activity in the interior of the Sun and how this impacts its total energy output measured as solar irradiance.

Variations in solar irradiance lead to heating of the upper layer of the Earth’s atmosphere

  • They also influence the transport of solar energy towards the planet’s surface.
  • The magnetic activity through the solar background magnetic field which occurs in the form of two magnetic waves inside the Sun.

Sun is Loosing its Shine | UPSC

SOURCES : NOAA

MAUNDER MINIMUM

  • During the Maunder Minimum in the middle ages, the solar irradiance went down by 0.22 per cent or 3 watt per square metre (W/sqm) in 1710 AD when the period ended.

This brought down the temperatures in the Northern Hemisphere, especially in Europe, by 1-1.5 degree Celsius. 

  • This also led to frozen rivers, long cold winters and cold summers.
  • This happened because of the complex impacts of decreased solar activity on the abundance of ozone in the Earth’s atmosphere and North Atlantic Oscillation (NAO).
  • The NAO is the balance between a permanent low-pressure system near Greenland and a permanent high-pressure system to its south, was in a negative phase during the Maunder Minimum.
  • This plunged Europe into colder-than usual temperatures.

There is another reason for the cooling is sun’s magnetic field, which shields the Earth from harmful cosmic and galactic rays

  • In the absence of the shielding more rays reaching the Earth and forming high clouds in the atmosphere, it is leading to the cooling.
  • The planet’s temperature might plummet by 1°C during the current grand solar minimum.

WORK IN PROGRESS

  • The sun’s activity is not completely understood.
  • Scientists takes six months to a year to just decide upon what exactly is happening in the Sun from observations.
  • On May 29, a NASA spacecraft observed a family of sunspots that were associated with the biggest solar flare.

A solar flare is a burst of activity on the sun’s surface accompanied by an ejection of particles known as the coronal mass ejection.

  • When the flares are big enough or called as solar maximum — they can disrupt satellite communications.

      IASbhai WINDUP: 

  • Some scientists also predict that the solar minimum cooling might cause a Little Ice Age and offset the rising temperatures due to global warming.

The National Aeronautics and Space Administration (NASA) is not very sure about such a conclusion.

  • It said even during a Grand Solar Minimum, the decrease in climate forcing would only be worth as much as three years of carbon dioxide growth in the atmosphere.
  • NASA also said the impact of global warming would be six times greater than the cooling caused by the Grand Solar Minimum.
     SOURCES:DownToEarth | Sun is Loosing its Shine | UPSC

DISCOVER MORE : SCIENCE AND TECHNOLOGY

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