Table of Contents
NOTES
How does the Juno Mission of NASA help to understand the origin and evolution of the
Earth?
(150 words, 10m, asked in UPSC Mains-2017 GS Paper-1)
NOTES
•Juno is a NASA space probe orbiting the planet Jupiter.
•It was built by Lockheed Martin and is operated by NASA’s Jet Propulsion Laboratory.
•The spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011.
FATE
After completing its mission, Juno will be intentionally deorbited into Jupiter’s
atmosphere.
Juno is the second spacecraft to orbit Jupiter, after the nuclear powered Galileo orbiter,
which orbited from 1995 to 2003.
NOTES
How does the Juno Mission of NASA help to understand the origin and evolution of the Earth?
Formation and evolution of the Solar System.
FORMATION AND EVOLUTION OF THE SOLAR SYSTEM
The nebular hypothesis, was first developed in the 18th century by Emanuel Swedenborg,
Immanuel Kant, and Pierre-Simon Laplace.
NOTES
• After the birth of Sun, a nuclear fusion in its center caused a great wind, which blew away remaining gas and dust in the vast regions of our solar system.
• Over the period of time, these giant clouds of gas and dust collapsed and formed planets.
• In the inner solar nebula, the terrestrial planets (Mercury, Venus, Earth, Mars) were too hot to hold the volatile gases. Hence their composition is (1) core: is metallic (2) mantle: is silicate (3)
atmospheres: is thin.
• But, In the outer solar nebula, temperatures were cool enough for the abundant gases to accumulate.
•As a result, the Jovian planets (Jupiter, Saturn, Uranus, and Neptune) are gas giants- made up of hydrogen, helium, ammonia and methane. But, we don’t know much
about their core and mantle.
NOTES
• Scientists believe that Earth’s hydrogen and helium were stripped off because of the solar winds. But cooling of the Earth released the gases and water vapor from inside its solid mass.
This process is known as ‘Degassing‘.
• Subsequent condensation of water vapor resulted into formation of oceans over the Earth. Later, life originated in these oceans as complex organic molecules and unicellular bacteria.
JUPITER
• Unlike Earth, the solar winds couldn’t blow away Jupiter’s hydrogen and helium- because of the distance.
• So, Jupiter’s atmosphere ought to have evolved from a mechanism other than ‘degassing’. We’ve to study this mechanism to refine our own ideas of how Earth’s atmosphere was born?
• Jupiter’s gravitational influence is said to be so enormous that it affects orbits of all planets. JUNO Mission’s gravitational readings will refine our understanding of Earth’s annual journey around the Sun.
•Jupiter’s Great Red Spot Could Disappear Within 20 Years
•The massive storm — larger than Earth itself — was first spotted in 1830, and observations from the 1600s also revealed a giant spot on Jupiter’s surface that may have been the same storm system. This suggests Jupiter’s Great Red Spot (GRS) has been raging for centuries.
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