Test: Introduction to Earth & Universe- 2 - UPSC MCQ

The Goldilocks Zone refers to the habitable zone. The habitable zone is the area around a star where it is not too hot nor too cold for liquid water to exist on the surface of surrounding planets.

Collision among the dust particles started the process of aggregation and accretion around the bigger particles which became the embryos of the future planets.

With the passage of time these embryos captured more and more matter and thus grew in size to become asteroids which in turn grew in size due to continuous accretion of nearby matter around them and thus they became planets.

Aurora is the name given to the luminous glow in the upper atmosphere of the Earth which is produced by charged particles descending from the planet’s magnetosphere. Some of these particles penetrate the ionosphere and collide with the atoms there.

This results in an excitation of the oxygen and nitrogen molecular electrons. The molecules get back to their original state by emitting photons of light which are the aurorae.

Effects of Geomagnetic storms

• The ionosphere gets heated and distorted, which makes long-range radio communication difficult.
• Ionospheric expansion can increase satellite drag, and it may become difficult to control their orbits.
• Geomagnetic storms disrupt satellite communication systems like GPS.
• Astronauts and high-altitude pilots would face high radiation levels.
• Electric power grids would see a high increase in voltage that would cause blackouts

Black hole has very high density as a result of which it has very high gravitational force. Therefore no object whether it is particle or radiation, can come out of it.

Statement 1 is correct as comets are indeed icy balls that form in the outer solar system.

Statement 4 is also correct because comets are remnants from the solar system's formation.

However, Statement 2 is incorrect; comets typically have elliptical orbits rather than circular ones, which cross the orbits of planets.

Additionally, Statement 3 is inaccurate because comet surfaces are composed of volatile materials that sublimate (transition from solid to gas) when nearing the sun, rather than being warm and fickle.

Therefore, only statements 1 and 4 are correct.

According to the Collision Hypothesis proposed by Harold Jeffreys, there were three stars in the Universe before the origin of the solar system. primitive sun, the ‘companion star’ and the ‘intruding star’ which was moving towards ‘companion star’.

The most common method for detecting exoplanets is the radial velocity method, which involves measuring the Doppler shift in a star’s spectrum caused by the gravitational tug of an orbiting planet. This shift indicates the star’s wobble, revealing the presence of an exoplanet.

• Statement 1: "It is a distant region of the solar system located beyond Neptune, containing icy bodies and dwarf planets."
  Correct — The Kuiper Belt lies beyond the orbit of Neptune (approximately 30 to 50 AU from the Sun). It contains numerous icy objects and several recognized dwarf planets such as Pluto, Haumea, and Makemake.

• Statement 2: "It serves as the origin for many short-period comets."
  Correct — The Kuiper Belt is the primary source of short-period comets (those with orbital periods less than 200 years). These comets originate from this relatively flat and disk-like region of icy bodies.
  
  Therefore, Correct Answer - Option C