MAANASI
What do we know about the
Earth
Solar System and
Universe?
Black Holes
Scientists estimate
there are ten million to 1 billion
black holes in the milky way alone.
(science.nasa.gov)
Black Holes aren't in the Solar System.
There are in space. A Black Hole, is a region
of spacetime, where gravity is extremely strong
that nothing can escape from it. "The theory of
general relativity predicts that a sufficiently
compact mass can deform spacetime to form a
black hole. (Wikipedia)
Reasons Humans had For Studying
Space
In general, humans don't like
not knowing things. We are adventurous and
want to find answers. So we make up our own
stories and
theories as to why things are there and how
they happened. In this case, it's for the
Universe.
Many cultures had theories
on how the universe was made.
First Nations, Metis and
Inuit cultures made their own
theories/explanations for the
formation of the Solar System and
Universe.
Season wheels have been found to
depict annual changes.
Harvest and planting for crops.
When to hunt and cultivate fish
stocks.
Ptolomy:
Earth is spherical as not everyone
records a solar eclipse at the same time.
Planets orbits are complex epicycles.
Around the 11th century.
Islamic astronomers confirmed the idea of
The Earth being the centre of the Universe.
Explained more about epicycles.
Ancient Greeks
Identified that objects in the sky
appear with predictable regularity.
Was thought the solar system was
spherical. The Moon was reflecting off of
the light of the Sun.
Also believed the Moon is
closer to the Earth than the Sun.
Comets are formed by collisions of
planets. Motions of planets are controlled
by the mind. (Anaxagoras)
Motion of planets is caused by a fire at the
centre of the Universe.
The Moon, Sun and planets orbit the Earth.
(Study of Pythagorus)
Chinese had two theories.
One: Earth is within heaven,
heaven acts like a lid.
Two: Earth floats on the water
heaven contains.
Ancient Babylonians believed the
universe revolved around heaven and
Earth.
Bronze age cultures made a
bronze disc the represent the
cosmos. Nebra sky disc had a
crescent Moon, Sun, 32 stars and
3 arcs describing the sunset and sunrise in
summer and winter.
Ancient Mayans
has studied the phases
of the Moon. recurrence of eclipses,
and appearance of Venus. And carefully
calculated phases of Pleiades, the Sun,
Moon, Venus, Jupiter, Mars and
Saturn.
Make up their own theories and stories.
There were many conceptions of the universe held by
different civilizations and cultures.
Glooscap:
Indigenous believed that
Glooscap made the world
habitable for humans by arranging
and creating landforms, giving animals
their attributes, and
eliminating monsters.
Union of two beings:
In Taoist, Prakrti and Brahman
stories.
From pre-existing materials:
As in the Norse and Babylonian
Supreme Creator:
One being created all that is known>
In Judeo-Christian, Egyptian, Aztec, and
Buddhist.
Great Egg:
In Finnish, Chinese and Indian stories,
they believed that the Universe hatched from
one egg.
Sun
The Sun's size is massive.
One million Earths can fit
into the Sun.
Composition:
In terms of atoms.
The Sun is composed of
91% Hydrogen and 8.9% helium.
In terms of mass.
The Sun is about
70.6% Hydrogen and 27.4% helium.
Moon
Earth,
Moon
and Sun
are held together by
Gravity.
Has 8 Phases:
In which are a result
from the angle the moon
makes with the sun. The phases
of the Moon depend on how much of the Sun's
light is covering the Moon.
These phases also have
spiritual meanings.
Eg. Waning crescent.
The Moon must wax
(grow larger) and wane
(grow slimmer). Cycle repeats
every month.
New Moon:
When none of the Sun's light
is covering the Moon.
Full Moon:
When all of the Sun's light
is covering the Moon.
The moon reflects the Sun's light.
It doesn't have a light of it's own.
So it's a natural satellite.
Theory on how it was formed:
A Mars-sized body hit Earth, and made a
debris-ring that slowly collected into a
single natural satellite. However, there are many beliefs
on how the Moon was made.
Earth
Earth is one of the rocky planets.
So it is believed that it was formed
by the process of accretion from the
densest chunks of matter.
Earth is the third planet
that orbits the sun. The Moon
orbits the earth. It is the only
astronomical planet known to
have life.
Universe
"Space is big. Really big. You just won't believe how
vastly, hugely, mind-bogglingly big it is.
I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."
-Douglas Adams
The universe is expanding by the day.
Everything in space is in the universe.
Universe is extremely massive.
The earth and planets are so tiny
compared to the size of the
Universe.
The universe is believed to have formed
due to the Big Bang. Which is the universe
expanding from singularity 14 billion
years ago.
Star
Death of Star:
When a star has burned all of its
Hydrogen fuel, it becomes a Red Giant.
Which can be millions of metres across,
large enough to swallow Mercury and Venus.
"After puffing off its outer layers, the star collapses to form a very dense white dwarf." (www.esa.int)
This gravity causes regions of
greater density to form within the
nebula over time. Dense regions continue
to pull gas from less dense regions for
10 million years. This forms a protostar.
Protostar:
Mass and gravity of the protostar
increase, so it becomes a tightly
packed sphere of matter drawing
more matter into its core.
The force of gravity eventually causes
the atoms in the core of the protostar
to become tightly packed that the pressure
in the core rises, and nuclear fusion begins.
They form by parts of nebulas
collapsing on themselves. When a certain density is reached,
gravitational forces pull the gas and dust particles
making clumps form in the main cloud of the nebula.
Comet
Appear every 5-10 years.
Outgassing: When the comet begins to
release gases. Which produces a visible
atmosphere or coma.
"Cosmic snowballs of frozen gases., rock and
dust that orbit the sun."
(asteroids-comets-and-meteors)
Natural Sattelite
A natural satellite, is
a body that orbits another body (planet/dwarf planet) in
space. (oxfordlanguages)
Artificial Satellite
An artificial satellite, is
an artificial body placed in orbit
around the Earth tot collect
information or for communication.
(oxfordlanguages)
Celestial Objects
within the
Solar System
Celestial Objects:
Or astronomical bodies.
Stuff that fills empty space of the Universe.
It can be Planets, Stars, Moons. But there's
other celestial objects in the universe.
Properties:
They can be glowing. Such as stars, and galaxies.
Celestial objects come in different sizes. Galaxies will be
much bigger than stars.
Location, Appearance, Motion:
Stars move. They are so far away, so their appearance
won't show their movement. They appear as tiny glowing specks in the night sky.
Examples:
-Planetary Systems
-Nebulae
-Star Clusters
-Galaxies
Astronomical Phenomena:
Examples:
-Eclipse
-Stars forming
-Supernova explosions
How they can be best observed
from Earth:
A lot of celestial objects can be
observed from Earth by
looking at the sky.
Solar System
Solar Nebula Theory-How the solar system was formed.
Sun was formed like any other star.
In planetary nebulae a lot of other material is there.
Dust, Ice, Rock. called the protoplanetary disk.
Just as the sun forms, accretion occurs.
Evidence:
Most of the planets aside from Venus and Uranus rotate in the
same direction. All planets can be found orbiting the Sun on the same flat plane. Rocky planets and asteroids have a similar cross section. Observations of distance planetary nebula show the same stages of formation. Computer simulations based on observed data create a solar system almost identical to the existing one.
Problems with the Model:
Cannot yet be explained how material pulled towards a star
or planetesimal loses enough momentum to change its orbit.
Explanation of the mechanism of how particle clumps turn into planetesimals is unclear. Timescale for formation of the gas giants are unclear. Gas giants can migrate inwards as they interact with the protoplanetary disk.
Planets Formation:
Process of accretion from densest chunks formed four of the planets. Mercury, Venus, Earth, Mars.
When planetesimals reach about 1 km in diameter, they begin to accrete each each other, and continue growing larger. Estimated there were only 100 or so planetesimals in our solar system, when it began to form.
Other 4 larger planets formed from gases, which are much less dense, therefore found much further away from the Sun than the rocky ones. Process of formation is fairly the same.
Major Components:
Other than planets, the solar system consists of
-Sun
-Moon
-Comets
-Dozens of Moons
-Millions of asteroids
-Dwarf Planets. eg. Pluto
A lot of solar system models show the planets very close together. In comparison to how massive the universe is, the planets are very small and far away from each other.
The Solar System has eight planets:
-Mercury
-Venus
-Earth
-Mars
-Jupiter
-Saturn
-Uranus
-Neptune
All orbit the Sun.
