Note4Students
From UPSC perspective, the following things are important :
Prelims level: Planetary Alignment
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:
- Conjunction: Two or more planets appear close to each other in the sky.
- Small Alignment: Three planets align in a visible line.
- Large Alignment: Four or more planets appear aligned from Earth’s perspective.
- 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:
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- August 2025: Expected four-planet alignment.
- May 2492: The next predicted full planetary alignment of all eight planets.
PYQ:[2019] On 21st June, the Sun: (a) does not set below the horizon at the Arctic Circle |
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