1. Nebular Hypothesis, first proposed by --
a) Immanuel Kant
b) Simon Laplace
c) Thomas Chamberlin
d) Henry Norris Russell
Answer. a) Immanuel Kant
1. The Nebular Hypothesis, which explains the origin of the solar system, including Earth, was first put forward by German philosopher Immanuel Kant (1755).
2. It was later revised by French mathematician Pierre-Simon Laplace (1796). Therefore, the Kant–Laplace theory is also called the Nebular Theory.
3. The Solar System formed from a huge rotating cloud of gas and dust called a nebula.
4. It is the first or oldest hypothesis that explains the formation of the solar system.
2. The planetesimal hypothesis was proposed by ---
a) Sir James Jeans
b) Harold Jeffreys
c) Thomas Chamberlin
d) Henry Norris Russell
Answer. c) Thomas Chamberlin
1. The planetesimal hypothesis ( 1905) was proposed by Thomas Chamberlin and Ray Maulton.
2. As per the planetesimal hypothesis, A nearby star passed close to the Sun. Solar material was pulled out from the Sun. This material cooled into many small bodies called planetesimals; later they combined and formed the planets.
3. The tidal hypothesis was first proposed by
a) Immanuel Kant
b) Simon Laplace
c) Thomas Chamberlin
d) Harold Jeffreys
Answer. d) Harold Jeffreys
1. The tidal hypothesis was first proposed by Sir James Jeans and Harold Jeffreys in 1917.
2. The tidal hypothesis is also known as the Jeans-Jeffreys Tidal Theory.
3. As per the tidal hypothesis, a massive star passed near the Sun. Strong tidal forces pulled out a cigar-shaped stream of solar matter. This matter condensed into planets
4. The idea of the Binary Star Hypothesis was put forward by
a) Sir James Jeans
b) Henry Norris Russell
c) Thomas Chamberlin
d) Gerard Kuiper
Answer. b) Henry Norris Russell
1. The idea of the Binary Star Hypothesis was put forward by Henry Norris Russell in 1937. Later refined and expanded upon by British astronomer R.A. Lyttelton.
2. As per the Binary Star Hypothesis, the Sun originally had a companion star. The companion exploded or disintegrated. Debris formed planets.
5. The Protoplanet Hypothesis was proposed by
a) Sir James Jeans
b) Henry Norris Russell
c) Thomas Chamberlin
d) Gerard Kuiper
Answer. d) Gerard Kuiper
1. The Protoplanet Hypothesis was proposed by Gerard Kuiper in the 1950s. It is the neo-nebular hypothesis theory.
2. As per the Protoplanet Hypothesis, a rotating cloud of gas and dust formed a disk around the young Sun. Condensations in the disk formed protoplanets. Protoplanets developed into planets.
6. The Earth formed about how many years ago?
(a) 3.0 billion years ago
(b) 3.5 billion years ago
(c) 4.0 billion years ago
(d) 4.5 billion years ago
Answer. (d) 4.5 billion years ago
Earth formed about 4.54 billion years ago.
7. The Solar System formed about how many years ago?
(a) 5.8 billion years ago
(b) 5.4 billion years ago
(c) 4.6 billion years ago
(d) 4.5 billion years ago
Answer. (c) 4.6 billion years ago
Age of the Solar System → 4.6 billion years.
Universe age: 13.8 billion years
8. The Life was originated on Earth about
( UPPSC-Assistant-Professor, Government Degree College, 2017)
(a) 3.0 billion years ago
(b) 3.5 billion years ago
(c) 4.0 billion years ago
(d) 4.5 billion years ago
Answer. (b) 3.5 billion years ago
Life originated on Earth about 3.8 billion years ago ( As per NCERT).
9. Consider the following statements:
1. The Earth was formed approximately 4.5 billion years ago.
2. The Earth formed from a giant cloud of gas and dust called a nebula.
3. The Big Bang Theory explains the origin of the Solar System.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (a) 1 and 2 only
Statement 1 is correct: Earth formed about 4.54 billion years ago.
Statement 2 is correct: The Solar System formed from a solar nebula.
Statement 3 is incorrect: The Big Bang Theory explains the origin of the Universe, not the Solar System.
10. Which one of the following theories is most widely accepted regarding the origin of the Moon?
(a) Nebular Hypothesis
(b) Planetesimal Hypothesis
(c) Giant Impact Theory
(d) Tidal Hypothesis
Answer: (c) Giant Impact Theory
According to the Giant Impact Theory, a Mars-sized body called Theia collided with the young Earth.
The debris produced by this collision later formed the Moon.
This is the most accepted modern explanation for the origin of the Moon.
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