Class 11 Physical Geography _ The Earth Flashcards
Early Theories about origin of earth
- Nebular Hypothesis
- Binary theories
Chamberlain and Moulton
Otto Schmidt + carl Weizascar
Nebular hypothesis
Immanuel Kant + revised by Laplace
the planets were formed out of a cloud of
material associated with a youthful sun, which
was slowly rotating.
Otto Schmidt and Carl Weizascar
revised the ‘nebular hypothesis’
They considered that the sun was surrounded by solar nebula containing mostly the hydrogen and helium along with what may be termed as dust.
The friction and collision of particles led to formation of a disk-shaped cloud and the planets were formed through the process of accretion
Binary theories
Chamberlain and Moulton
a wandering star approached the sun. As a result, a cigar-shaped extension of material was separated from the solar surface. As the passing star moved away, the material separated from the solar surface continued to revolve around the sun and it
slowly condensed into planets
Sir James Jeans and later Sir Harold Jeffrey supported
Modern theories on Origin of Universe
Big Bang theory aka Expanding Universe hypothesis
Edwin Hubble proved that Universe is expanding, 1920
A galaxy starts to form by
accumulation of hydrogen gas in the form of a very large cloud called nebula –> develops localized clumps of gas –> clumps grow into denser gaseous bodies –>stars
light year is a measure of
distance
First 4 planets are called
Last 4 planets are called
inner planets/Terrestrial planets
outer planets/Jovian/Gas giants
Jovian means
Jupiter like
decreasing order of density of planets
Earth, Mercury, venus, Mars, Neptune, Jupiter, Uranus and Saturn
Planets without moons
Mer, Ven
No. of Moons of Mars
2
Theories of formation of Moon (2)
Sir George Darwin - earth + moon– single rapidly rotating body in the shape dumbbell shaped body
broke off
Not accepted
- Giant impact or big splat
