Why in the News?

For centuries, astronomers and observers have recorded strange, short-lived visual events on the Moon’s surface, known as Transient Lunar Phenomena (TLPs).

About Transient Lunar Phenomena (TLPs):

• What is it: Short-lived flashes, glows, or hazy patches observed on the Moon’s surface, lasting seconds to several hours before fading.
• Observation History: Reported for over a thousand years, including Apollo 11 astronauts (1969) who noted a luminous lunar glow.
• Appearance Types: Include reddish glows, star-like flashes, and mist-like obscurations.
• Active Regions: Concentrated around Aristarchus and Plato craters, considered the most dynamic lunar zones.
• Scientific Implication: Suggests that the Moon remains geologically active, contradicting earlier assumptions of total dormancy.
• Theories on Origin: Scientists propose several explanations for TLPs:

1. 1. Lunar Outgassing: Trapped gases such as radon or argon may escape through fissures, triggered by gravitational stresses or surface heating, causing dust or gas to glow or reflect sunlight.
   2. Meteoroid Impacts: Frequent meteoroid collisions on the Moon’s airless surface produce brief, intense flashes, accounting for many observed TLPs.
   3. Electrostatic Dust Levitation: Charged lunar dust particles, activated by solar radiation, may levitate and scatter light, producing transient luminous effects.
   4. Atmospheric Distortion on Earth: Some TLPs may be optical artifacts, caused by turbulence or refraction in Earth’s atmosphere altering the Moon’s apparent brightness or colour.

Recent Research and Monitoring:

• Observation Technology: Use of automated telescopes and CCD (charge-coupled device) imaging systems for real-time detection.
• Space Missions: NASA’s Lunar Reconnaissance Orbiter (LRO) and ISRO’s Chandrayaan series monitor gas release and new impact craters.
• Spectroscopic Evidence: Studies of Aristarchus Plateau show episodic radon emissions, supporting the outgassing theory.
• Integrated Monitoring: Global programs combine optical, seismic, and spectrometric data to validate events.
• Scientific Aim: To understand lunar surface dynamics, internal processes, and signs of ongoing geological activity.

Why in the News?

Viewers across Asia, Australia, and parts of Africa witnessed a Blood Moon on 8th September, a spectacular form of total lunar eclipse visible.

About Lunar Eclipse:

• Overview: Happens when Earth comes between Sun and Moon, blocking sunlight from reaching the Moon.
• Earth’s Shadow:
  • Umbra: Dark central shadow, causes total or partial eclipses.
  • Penumbra: Outer shadow, causes faint dimming.
• Types:
  1. Total Eclipse: Moon passes fully through umbra.
  2. Partial Eclipse: Only part of Moon enters umbra.
  3. Penumbral Eclipse: Moon passes through penumbra with subtle darkening.
• Frequency: Occurs 2–4 times per year, visible from different regions.

What is Blood Moon?

• Meaning: Refers to the reddish glow of the Moon during a total lunar eclipse.
• Cause: Rayleigh scattering in Earth’s atmosphere.
  • Short wavelengths (blue, violet) scatter away.
  • Longer wavelengths (red, orange) bend around Earth and light the Moon.
• Colour Intensity:
  • Presence of dust, aerosols, volcanic ash deepens the red shade.
  • Cleaner atmosphere produces a lighter red or orange.
• Historical Insight: Medieval records of Blood Moons helped identify volcanic eruptions between 1100–1300 CE, confirmed by a 2023 University of Geneva study.

Significance:

• Scientific: Acts as a natural indicator of atmospheric composition, dust, and pollution; helps model planetary atmospheres.
• Historical/Environmental: Provides evidence of past volcanic events and climate conditions.
• Cultural: Linked to myths and superstitions, though harmless scientifically.
• Public Engagement: Widely followed celestial event that aids astronomy outreach and awareness.