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Lecture

EPSC 180 Lecture Notes - Solar Wind


Department
Earth & Planetary Sciences
Course Code
EPSC 180
Professor
Olivia Jensen

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EPSC180 - Lecture 1 Notes
Introduction:
Perihelion: the condition of being close to the sun
Aphelion: the condition of being far away from the sun
Perihelion and aphelion determines the seasons based on how far or close it is to the sun, thus determining the amount of
sunshine and heat
The Earth rotates at an axis; thus (based on where we are) in Winter the Earth covers itself in most of the Northern shadow.
In the summer, the Earth is inclined towards the sun and gets most of the sun
Harvard Commencement Video: A Private Universe
While most people think the Earth circles in the sun in an ellipses, the reality is that the Earth rotates circular to the sun, with
no difference in distance. What causes the different seasons is really based on the axis inclination the Earth is towards the
sun
Cosmic Collision Video:
Comets begin as chunks of ice and rocks that orbits around the sun, far beyond our solar system. If a comet orbits closer to
the sun, it’s icy surface melts from solid to gas and will unleash a lot of gas and chunks of rocks which makes up a tail which
is what we see
Collisions can be beneficial in our galaxy
Theory of moon creation:
Back in the early days after the Earth was formed, a comet nearly the size of the Earth collided with the Earth, nearly
destroying the Earth.
The collision spewed lots of magma and shattered into many pieces/chunks of rocks. Due to gravity from the Earth, this
kept the rocks suspended and over time, through the gravitational pull from the Earth fused these chunks together
(snowball effect) into what is now the moon (less than a month)
The collision between the comet and the Earth made life possible because the collision tilted the Earth’s rotation, thus
allowing for seasons and the moon’s gravitation pull gives rise to tides
System of the Sun:
The sun is a star. It’s dark patches are sun spots; each of which is roughly the size of the Earth. Sun spots are dark be-
cause they are the coolest place on the sun (roughly 8000°F)
The sun creates its immense heat through internal collisions between protons (fusion which releases lots of energy
through light)
Some of the light charged particles leaves the sun in a continuous stream known as solar wind which blows into the so-
lar system at one million miles/hour
If solar winds hit the Earth, it would blow away half the atmosphere and remove large quantities of water; thus destroy-
ing life on Earth. Fortunately, the Earth is protected by magnetic fields generated by the Earth’s iron core which repeals
the solar wind to the North and South poles (causing us to see the Aurora Borealis)
Asteroids are pieces of rocks and metal left over from the first few millions years when the planets were forming. Most of the
asteroids are located in an orbit between Mars and Jupiter known as Kepler’s Belt. Some are closer
65 million years ago, an asteroid from Kepler’s Belt did hit the Earth. The asteroid was about 7 miles wide and it collided
near Mexico, South America known today as the KT Boundary. The indent from the hit resulted in a fireball that incinerated
everything in its proximity and blasted rocks and Earth into space. As the material came back down, it heated the Earth and
caused smaller, but a wider range of impact sites
For an hour, the temperature on Earth rose 500°F, and the resulting smoke covered the Earth for at least six months.
Between massive destruction caused by the asteroid impact and damage done by volcanic eruption and changing sea
levels, nearly three quarters of life on Earth was exterminated. The age of dinosaurs was over (though some dinosaurs
and mammals evolved to present day birds and other mammals)
Scientists have wondered what would happen if another asteroid were to hit Earth. They couldn’t blast it as more chunks
would come towards the Earth. They devised a new plan which would use gravity from something like a space shuttle or a
satellite to change the orbit of the asteroid which would require a few years
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