Lena Zura

Mr. Stever p.5

10/7/24

Origins project

People have debated how the universe came to be for a long time. One of the most

widely believed theories is the big bang theory. This theory states that the universe started 13.7

billion years ago. It says the universe started from one small point and kept expanding and that

it's still expanding to this day. When the universe first started, it used to be made up of small

particles mixed with light and energy but then they grouped together and formed atoms which

eventually formed the rest of everything. The universe is still expanding today, and it will

forever keep expanding according to the big bang theory (nasa, 2024). A different theory that

some people believe in is the cyclic theory which is that the universe is expanding but that one

day it will start condensing and become nonexistent again, only for it to start over. People

believe that this has happened multiple times already, a cycle of expansion and condensing.

The theory states that the universe will start rapidly expanding after 14 million years and after

trillions of years of expansion it will come to a standstill which is when the cycle is ending, and

the matter and radiation is spread out too thin to continue expansion. Eventually new matter

and radiation from an energy field causes the cycle to revive and continue to expand until the

cycle repeats (Princeton uni, 2002). Most people don't believe in the cyclic theory because

there isn't really evidence to support it. In fact, there is evidence against it because of the red

shift theory, which says that objects moving away emit red light. You can see lots of red light
proving our universe is expanding, which is evidence for the big bang theory. However, some

people think that hot spots could be evidence of the cyclic theory stating they are black holes

evaporating from before the big bang, (cartlidge, 2018). However the universe came to be is

pretty crazy.

After the creation of the universe eventually the solar system was created, 4.6 billion

years ago. Gas and dust coming from a collapsed solar nebula condensed to form the sun and

then the planets. The gas and space dust were knocked together by a shock wave coming from

the collapsing super nova. This theory is called the condensation theory. The condensation

theory also explains how the moon was theoretically formed. It theorizes that the moon was

formed at the same time as the planets. However, that is debated because the moon has more

lunar baking and doesn't have the same iron core as the earth (nasa). The planets formed with

spherical cores which were created by different things melting and settling because of density

stratification. Density stratification causes heavier elements, like iron, to sink and lighter things

to rise. (amnh). This leads to the cores of planets to be made of elements like iron. There is

another theory about how the solar system formed. It's called accretion theory which states

that gravity makes matter clump together and that this formed everything including helping

form the solar system. (rimmer, 2022). The accretion theory has a theory for how the moon

formed. They think that around 4.5 billion years ago something hit the earth and caused lots of

molten and debris to fly into space, because of accretion theory and gravity the debris

condesed together to form the moon. This is good evidence for accretion theory because it

explains why the moon has a different make up than the earth (nasa). The accretion theory

seems to be the most accurate because it is backed up by gravity, a scientific law. Accretion is
basically that gravity formed the solar system by making the space debris that was floating

around come together to form the planets. But of course, it would take more than just the

formation of the planet to eventually support the earth we have today.

The atmosphere was a very important step in earth becoming habitable. Back when the

earth was first forming the surface was covered in molten, but the molten was cooling and

forming the outer crust of our planet. The earth was covered in volcanoes and from the

volcanos gasses like co and co2 were released, which formed the first atmosphere from

outgassing. This was after the magnetic poles formed to protect the atmosphere (forces of

change). Outgassing is the release of gases from things like volcanoes and thermal vents usually

letting out gasses like co, co2, h2o, hcl, ch4, nh3, n2 and sulfur gasses from inside the earth.

This formed the first atmosphere which is very different from the one we have today. This

atmosphere had no free oxygens (Oregon state u). There were 3 atmospheres formed in our

planet's lifetime, including the one we have today. The Primary atmosphere was the first one,

made of light gases that were there at formation. These came from the solar nebula, so they

were gases like hydrogen and helium (oregon edu). The Secondary atmosphere which is the one

that formed after the first one was lost. It wasn't made of elements like hydrogen and helium

anymore, but it still had the volatile elements because there were still many volcanos on the

earth even though the planet had changed significantly (briticania). The third atmoshpere is the

one we have today, the Tertiary atmosphere. This one was formed because co2 dissolved into

the oceans and there was an increase of oxygen in the atmosphere. When bacteria and algae

started to form they created oxygen which went into atmosphere and changed it to the one we

haved today which is breathable and suitable for the life forms we have today (scijinks). One of
the reasons our atmosphere is still protecting us is the magnetic field. Earth is protected by the

magnetosphere which is different from the other planets. It's made by powerful sources in the

center of the earth and protects the atmosphere from erosion by solar winds, particle radiation

and cosmic rays, which could destroy the whole atmosphere and life on earth. Sometimes,

some solar rays pass, but they are much less harmful than if we didn't have our magnetic field

(nasa). The atmosphere protects us so that we can survive.

The earth wouldn't be the one we know today without the oceans. Around 3.8 billion

years ago the Oceans started to form, gradually over many years. The early earth was made of

molten rock coming out of the volcanoes. Water vapor and gases came out of earth through

vents. They cooled down the earth’s surface enough that it eventually started to rain and slowly

filled up the oceans (nos). Water condensed in the atmosphere and became rain which filled up

the earth. One of the theories of how water got on the earth and in the atmosphere is through

the steam from volcanoes and vents. However, there are other theories of how water came

here. Some people think water may have also been deposited by ice comets that came to the

earth and then melted down. Eventually the water turned into condensation and rained down

on the earth (pbs). The oceans are very deep as we know, the giant basins where the oceans

currently are were not already there when the earth was first forming. The ocean can cause

decomposition of rock, also known as weathering, which wore down the earth and caused the

giant basins the oceans are in. The oceans are a very important part of earth and life on earth

because without the oceans, earth as we know it know would not be the same. The oceans

allowed earth to be habitable and for life to form.

underwater in deep sea vents where conditions allowed for life because they weren't subjected

to the harmful atmosphere and ice on the surface. Others think that life formed in oceans

under the ice because that's where life was possible, since the surface didn't support life. An

additional theory some people think is that life was brought to earth from a meteorite and that

it was formed somewhere else. People think that the time frame of when earth cooled enough

to support life wasn't long enough to support the amount of evolution that fossil records show.

This leads them to think that life was created somewhere else and brought to earth. This is

called panspermia (nasa). For many years people have been trying to figure out how to create

life. Stanley millers' theory was what he tested to see how inorganic materials could build life.

He wanted to figure out how life was first created on earth. He tried to replicate earth's early

conditions, when life would have formed to see how it was done. He was successful in making

organic forms out of inorganic material. With his experiment he successfully created amino

acids (britnicaia). This still doesn't fully show how life was created on earth because we can't be

fully sure of the conditions back then, that is one of the reasons why stanlley miller ran his

experiment many different times, and he got organic life forms (britannica). However, life didn't

keep on going as amino acids. It kept changing and adapting. Eventually, because of how the

earth was changing, the life that had formed changed to rely on oxygen. Oxygen is very

necessary for life to exist, it's needed for cellular respiration which is how we breathe, humans

can’t exist without oxygen. However, early life didn't have oxygen so they relied on other

compounds. Eventually, we developed to need oxygen instead because it became plentiful in

atmosphere. It took billions of years but eventually life formed in the universe.

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