Earth SCIENCE LESSON FOR QUARTER 1

1. Lesson 2
THE ORIGIN OF
THE SOLAR
SYSTEM

2. Objective
Describe the different
hypotheses explaining
the origin of the solar
system

4. Scientists have long debated the origins of the
solar system.
• In the 1600s and 1700s, many scientists
thought the sun formed first and produced
materials which later formed the planets.

5. HYPOTHESES
EXPLAINING THE
ORIGIN OF THE SOLAR
SYSTEM

6. The Protoplanet Theory
According to this theory, dense interstellar
cloud produces a cluster of stars
-small blobs spins randomly resulting to the
low rotation of stars that lead to the formation
of “planetary blobs”
The 'planetary blobs' split into planets and
satellites.

7. Planetesimal Hypothesis
 According to this theory, tiny solid
particles or "planetesimals" in the
protoplanetary disk clumped together
through collisions and gravitational
attraction to form larger bodies, which
eventually became planets.
This process is often considered a key
step in the formation of terrestrial planets

8. Binary Star Hypothesis
-proposed that the Sun may have
originally been part of a binary star
system, where two stars orbit a common
center of mass
-the second star was ejected from the
system, leaving our Sun and the planets
in their current configuration

9. The Modern Laplacian Theory
French astronomer and mathematician Pierre-Simon
Laplace first suggested in 1796 that the Sun and the
planets formed in a rotating nebula which cooled and
collapsed
 The theory argued that this nebula condensed into
rings, which eventually formed the planets and a central
mass - the Sun
Eventually, after the core has been slowed, its
temperature rises and the dust evaporates
 The slowly rotating core becomes the Sun
The faster rotating cloud outside it become the planets

10. The Accretion Theory
The Sun passes through a dense
interstellar cloud
-in a reasonable time the terrestrial
planets form, but the gaseous planets take
far too long to form
 The theory does not explain satellites or
Bode's law and is therefore considered the
weakest of those described here

11. Tidal Hypothesis
-suggests that a passing star or another
massive celestial object came close to
the early Sun, causing tidal forces to
disrupt the Sun's outer layers
These ejected materials then coalesced
to form the planets and other objects in
the solar system.

12. The Nebular Hypothesis
proposed by Immanuel Kant and further
developed by Pierre-Simon Laplace in the
18th century
one of the most widely accepted
explanations for the origin of the solar
system
It suggests that the solar system formed
from a giant rotating cloud of gas and dust
called the solar nebula

13. As the nebula contracted and
flattened due to gravity, it began
to spin faster, forming a spinning
disk
 In the center, the Sun formed,
and in the outer regions, dust and
gas particles came together to
form planets, moons, asteroids,

15. In 1992 the Hubble Space
Telescope obtained the first
images of proto-planetary disks
in the Orion nebula
 They are roughly on the same
scale as the Solar System and
lend strong support to this

16. The Capture Theory
-suggests that the Sun captured already-
formed planets from another star system
-this theory proposes that these planets were
passing through our region of the galaxy, and
the Sun's gravity captured them, causing
them to become part of our solar system
However, this hypothesis is less widely
accepted than the nebular hypothesis
because it's challenging to explain the
composition and orbital characteristics of the