Mudumal Megalithic Menhirs

Context: Mudumal menhirs in Telangana’s Narayanpet district are set to become the state’s second UNESCO World Heritage Site after being added to the tentative list in 2025.

What are Menhirs?

• Menhirs are large, upright, man-made stones, often tapered at the top.
• Origin of Term: Derived from Brittonic words “maen” (stone) and “hîr” (long),
• These stones are typically unworked or slightly shaped and vary in size, with some reaching several meters in height.
• Menhirs are found across Europe, Asia, and parts of Africa.
• The Mudumal Megalithic Menhirs
  • The Mudumal Megalithic Menhirs are an extraordinary archaeological site located in the Narayanpet district of Telangana, India. 
  • These standing stones date back approximately 3,500 to 4,000 years, the oldest known in India.
  • Purpose:
    • Found alone or in megalithic complexes.
    • Used for ceremonial, astronomical, or burial purposes.
    • Mudumal menhirs are believed to be an “astronomical observatory”, aligned with solstices.
    • One menhir is worshipped as Goddess Yellamma.
• Why UNESCO Recognition?
  • Ingenuity: These heavy stones reflect early humans’ knowledge of physics and astronomy.
  • Cultural Insight: Their construction reveals the values and worldview of ancient societies with no written records.

Birefringence: Double Refraction

About Birefringence

• Birefringence is the phenomenon exhibited by certain materials in which an incident ray of light is split into two rays, called an ordinary ray and an extraordinary ray, 
  • These rays are plane-(linear) polarized in mutually orthogonal planes, or circular-polarized in opposite directions (left and right).
• Reason: This phenomenon arises because the material has multiple refractive indices, causing light to bend differently in different directions.
• Anisotropic Nature: Birefringent materials are anisotropic, meaning they exhibit different optical properties along different axes.

How Refractive Index Affects Light?

• Refractive Index  is defined as the ratio of the speed of light in a vacuum to its speed in a given material.
• Refractive Index for different medium: Vacuum = 1, Air = 1.0003, Glass ≈ 1.5, Diamond ≈ 2.4.
• Birefringence Effect: Some materials alter light speed differently along various directions, resulting in double refraction.

Examples of Birefringent Materials

• Natural Materials:  Mica, Quartz, and Calcite exhibit natural birefringence.
• Synthetic Materials: Barium Borate and Lithium Niobate also display birefringent properties.
• Modified Birefringence: Can be induced by applying mechanical stress, electric fields, or magnetic fields.

Types of Birefringence

• Intrinsic Birefringence: Occurs in materials with non-cubic crystal structures, such as calcite and quartz.
• Stress-Induced Birefringence : Appears in isotropic materials like glass and plastics when subjected to mechanical stress.
• Electric Field-Induced Birefringence: Observed when an external electric field alters a material’s optical properties.

Applications of Birefringence

• Optics and Photonics: Utilized in polarizing filters, wave plates, and optical fibers.
• Material Science: Helps analyze stress distribution in transparent materials.
• Biology: Used in polarized light microscopy to study biological structures.
• Other Uses : Essential for LCD screens, optical switches, waveplates, frequency converters, and high-power lasers.

Impact of Air Pollution on Solar Power Generation

Context: A study by IIT Delhi, published in Environmental Research Letters, reveals that air pollution and climate change will significantly reduce solar panel efficiency in India.

• As the world’s fifth-largest solar power producer, India aims to generate 50% of its electricity from non-fossil sources by 2030. However, declining solar radiation due to pollution threatens this goal.

Key Findings of the Study

• Air pollution and climate change will impair solar panel performance.
• Solar efficiency is projected to decline by at least 2.3% by mid-century (2041-2050).
• This reduction translates to an annual electricity loss of 840 gigawatt-hours.

Impact of Air Pollution and Climate Change

• Airborne pollutants (particulate matter, aerosols, and clouds) obstruct sunlight, reducing the energy received by solar panels.
• Global dimming and brightening phenomena impact long-term solar radiation trends.
• Rising temperatures lower photovoltaic (PV) cell efficiency by heating them beyond optimal operating conditions.

Factors Affecting Solar Power Generation

• Solar radiation availability: The most critical determinant of solar panel efficiency.
• Temperature rise: Higher ambient temperatures further reduce PV performance.
• Wind speed : A secondary factor, impacting cooling efficiency.

Regional Variations in Solar Power Potential

• Northeast India and Kerala are expected to see increased solar power potential due to reduced cloud cover.
• Other regions may face a decline in solar efficiency due to persistent air pollution.

National Youth Parliament Scheme (NYPS) 2.0

Context: An upgraded version of the National Youth Parliament Scheme (NYPS) web portal, known as NYPS 2.0 has been unveiled by The Ministry of Parliamentary Affairs recently.

About National Youth Parliament Scheme (NYPS)

• Launched By: The Ministry of Parliamentary Affairs
• The web portal of the National Youth Parliament Scheme (NYPS) was launched on 26th November, 2019
• Aim: To expand the outreach of the Youth Parliament Programme of the Ministry to all the recognized educational institutions of the country.

About National Youth Parliament Scheme (NYPS) 2.0

• Eligibility: NYPS 2.0 is open to all citizens across the country regardless of economic status, gender, caste, creed, religion, race, region and place.
• The Unit of Participation: The unit of participation on NYPS portal is a registration not an institution
• Participation can be facilitated through the following ways:
  • Institution Participation: All educational institutions can participate in this category by organizing the Youth Parliament sittings.
    • Kishore Sabha: The students from classes VI to XII may be selected
    • Tarun Sabha: Under Graduate and Post Graduate level students may be selected.
  • Group Participation: A group of citizens can participate in this category by organizing the Youth Parliament sittings as per the guidelines available on the portal.
  • Individual Participation: An individual citizen can participate in this category by attempting a quiz on the theme of ‘Bharatiya Democracy in Action’.

Raisina Dialogue

Context: India is hosting the 10th edition of the annual Raisina Dialogue from March 17-19, 2025, with the theme “Kalachakra” (wheel of time).

About Raisina Dialogue

• Origin of Name: “Raisina Dialogue” is derived from Raisina Hill, a New Delhi seat of the Government of India and the Presidential Palace, Rashtrapati Bhavan. 
• It is India’s flagship conference on Geopolitics and Geoeconomics, 
• Hosted by: the Observer Research Foundation (ORF) and the Ministry of External Affairs, GoI.
• It is held annually, First Session Held in 2016.
• Objective: To share unique perspectives, concerns, and experiences that are essential for charting important pathways, building consensus, and strengthening communities for our common future.
• Organized on the lines of : 
  • Shangri La Dialogue (takes place annually in Singapore)  
  • Munich Security Conference (the 60th edition of which took place recently in February 2024)
• Conference Structure: 
  • It is a multi-stakeholder, cross-sectoral discussion, involving global policymakers like heads of states, cabinet ministers, and local government officials. 
  • It also includes major private sector executives, media members, and academia.

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