Subject: Space Technology

Why in the News?

On February 29, 2024, skywatchers worldwide witnessed a rare planetary alignment (parade) with seven planets—Mars, Jupiter, Uranus, Neptune, Mercury, Saturn, and Venus—lining up in the night sky.

What is Planetary Alignment?

• A planetary alignment occurs when multiple planets in the Solar System appear to line up in the sky as seen from Earth.
• This phenomenon happens because planets orbit the Sun in a flat, disc-shaped plane called the ecliptic.
• Although planets remain millions of kilometers apart, they seem to form a straight line from Earth’s perspective due to optical illusion and perspective.
• The term “planet parade” is also used to describe this occurrence when multiple planets become visible in the sky at the same time.

• Types of Planetary Alignments:

1. Conjunction: Two or more planets appear close to each other in the sky.
2. Small Alignment: Three planets align in a visible line.
3. Large Alignment: Four or more planets appear aligned from Earth’s perspective.
4. Full Alignment: All eight planets of the Solar System appear in a single line (very rare).

How often do Planetary Alignments occur?

• Planetary alignments are not uncommon, but their rarity depends on the number of planets involved.
  • Two- or Three-Planet Alignments: Occur multiple times a year.
  • Four- or Five-Planet Alignments: Visible every few years.
  • Six- or Seven-Planet Alignments: Appear every few decades.
  • Full Alignment (All Eight Planets): Extremely rare, occurs once every 170–200 years.

• Recent & Upcoming Alignments:

• • August 2025: Expected four-planet alignment.
  • May 2492: The next predicted full planetary alignment of all eight planets.

Why in the News?

US’s Firefly Aerospace’s Blue Ghost Mission 1 successfully landed on the Moon, becoming the second private mission to do so and the first to land upright.

What is ‘Blue Ghost’ Mission 1?

• Blue Ghost Mission 1 is a private lunar landing mission by Firefly Aerospace under NASA’s Commercial Lunar Payload Services (CLPS) program.
• It was launched aboard a SpaceX Falcon 9.
• It successfully landed on the Moon, at Mons Latreille, Mare Crisium.
• The mission is designed to operate for 14 Earth days (one lunar day).

Key Features of Blue Ghost Mission 1:

• Carries 10 scientific instruments, including a lunar soil analyzer, a radiation-tolerant computer, and a GPS-based navigation experiment to test satellite navigation on the Moon.
• Equipped with a high-definition imaging system to capture a lunar eclipse (March 14, 2024) and lunar sunset (March 16, 2024).
• Successfully navigated a rocky and cratered surface using hazard-avoidance technology, slowing from thousands of miles per hour to just two mph before touchdown.
• The lander is golden in color and about the size of a hippopotamus.
• It supports Artemis missions by testing lunar technologies and reducing costs for future human exploration.

Why in the News?

A new proposal published on October 29, 2024, suggests an experiment that could provide direct evidence for quantum gravity, unifying general relativity and quantum mechanics. A new experiment proposes testing weak gravitational fields at the quantum level, a historic breakthrough in physics if successful.

What is Quantum Gravity?

• Quantum Gravity is a theoretical framework that aims to unify general relativity (which explains gravity at large scales) and quantum mechanics (which governs subatomic particles).
• Since gravity behaves differently from the other fundamental forces in quantum mechanics, physicists have been searching for a theory that integrates gravity into the quantum world.
• General relativity treats gravity as the curvature of spacetime, while quantum mechanics describes forces through particle interactions.
• Gravity has never been directly observed in quantum form, unlike the other fundamental forces.
• Theories like String Theory and Loop Quantum Gravity attempt to explain quantum gravity but lack experimental validation.

Significance of the Experiment

• First Realistic Test for Quantum Gravity: Most quantum gravity theories rely on extreme conditions (e.g., black holes), making them impossible to test. This experiment provides a lab-based alternative.
• Testing Gravity at the Quantum Level: If a small mass in quantum superposition is influenced by gravity, it could prove gravity itself is quantum in nature.
• Weak Gravity Instead of Strong Gravity: Unlike previous studies focused on black holes, this experiment explores weak gravitational interactions, making it more feasible.
• Towards a Unified Theory of Physics: Proving quantum gravity could merge general relativity and quantum mechanics, solving a major gap in modern physics.
• Challenging Existing Theories: If results differ from both classical and quantum predictions, it could suggest a new force or a modified gravity theory.

Why in the News?

A new study has challenged previous assumptions, suggesting that Saturn’s rings could be as old as the Solar System (~4.5 billion years old).

About Saturn and Its Rings

• Saturn, the sixth planet from the Sun, is famous for its iconic ring system, made up of billions of ice and rock particles ranging in size from tiny grains to massive chunks.
• It is primarily composed of water ice (95%), with some dust and rocky debris.
• The rings are divided into seven main sections (A to G), with gaps like the Cassini Division.
• Scientists have debated whether the rings formed with Saturn (~4.5 billion years ago) or if they are only 100-400 million years old.
• Over time, tiny space rocks should darken the rings, yet they remain surprisingly bright.

Key Findings of the Study:

• Earlier estimates, based on Cassini data, suggested the rings were 100-400 million years old because they looked clean and bright.
• The new study suggests that micrometeoroid collisions remove dust efficiently, preventing the rings from darkening over time.
• High-speed micrometeoroid impacts (~108,000 km/h) cause dust to vaporize, rather than accumulate.
• The vaporized dust either escapes Saturn’s gravity, falls into the planet’s atmosphere, or gets ejected into space, keeping the rings pristine.
• 100 million years ago, the Solar System was stable, making ring formation unlikely.
• 4 billion years ago, the Solar System was chaotic, increasing the chances of violent planetary collisions that could have formed Saturn’s rings.

Why in the news?

India’s 4th generation deep-ocean submersible Matsya-6000 has successfully completed wet testing at Chennai harbor, paving the way for shallow-water demonstrations at depths of up to 500 meters by 2025.

About Matsya-6000

• Made of titanium alloy to withstand extreme oceanic pressure.
• Built with a 2.1-meter diameter sphere to accommodate three crew members.
• Moves at speed of 5.5 km/hr using multidirectional thrusters.
• Uses GPS, underwater acoustic positioning, and joystick-controlled maneuverability.
• Operates for 12 hours, with an emergency endurance of 96 hours.
• Includes emergency buoyancy modules and high–pressure-resistant escape hatches.
• Features robotic arms for sample collection.
• Uses high–resolution imaging and oceanographic sensors for deep-sea research.
• Future Trials:
  • Shallow-water tests up to 500m planned by late 2025.
  • Full deep-sea trials at 6,000m scheduled for 2026.

What is Deep Ocean Mission (DOM)?

• • The DOM launched by the Ministry of Earth Sciences (MoES) in 2021, aims to enhance India’s deep-sea exploration capabilities while supporting the Blue Economy policy.
  • It focuses on resource utilization, climate monitoring, and marine biodiversity conservation.

• Objectives of DOM:

• Develop advanced technologies for ocean mining, biodiversity assessment, and deep-sea surveillance.

• • Enable climate change research through real-time ocean data collection.
  • Establish a Marine Station for Ocean Biology for research on marine ecosystems and pharmaceuticals.
  • Support the Samudrayaan Mission, which includes the development of Matsya-6000, India’s first deep-ocean human submersible.

• Structural Mandate of DOM:

• • Deep-ocean survey and identification of polymetallic nodule and sulfide deposits.
  • Harnessing ocean energy through wave, tidal, and thermal sources.

Why in the News?

The European Space Agency’s (ESA) Euclid Space Telescope has captured a rare Einstein Ring around a galaxy nearly 590 million light-years away from Earth.

What is an Einstein Ring?

• An Einstein Ring is a circular ring of light caused by gravitational lensing, a phenomenon predicted by Einstein’s General Theory of Relativity.
• It occurs when a massive celestial object (like a galaxy) bends and magnifies light from a more distant background galaxy that lies directly behind it.
• The recent discovery by ESA’s Euclid telescope identified an Einstein Ring around NGC 6505, located 590 million light-years away, acting as a lens for a distant galaxy 4.42 billion light-years away.
• Features of an Einstein Ring:
  • Perfect circular shape (only if source, lens, and observer align precisely).
  • Example of strong gravitational lensing, distorting background light.
  • Extremely rare (found in less than 1% of galaxies).
  • Not visible to the naked eye, observed only with advanced space telescopes like Euclid or Hubble.

Significance of the Discovery:

• Reveals Dark Matter: Helps indirectly map dark matter, which makes up 85% of the universe.
• Magnifies Hidden Galaxies: Makes faint, distant galaxies visible for study.
• Measures Universe’s Expansion: Tracks how light stretches over time, refining cosmological models.
• Confirms Einstein’s Theory: Proves light bends in curved space-time, supporting gravitational lensing theory.
• Demonstrates Euclid’s Capabilities: Shows Euclid’s high-resolution potential, promising more discoveries.