Earth and Space Science Topic Test

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name and briefly explain the 4 spheres of earth

1. biosphere - the living parts of the earth, all organisms make up the biosphere

2. hydrosphere - the mass of water lying over, on, or under the surface of Earth as oceans, seas, lakes and rivers

3. lithosphere - consists of solid rock. it's the cold, brittle elastic outermost shell of the earth

4. atmosphere - consists of gases, mostly nitrogen, oxygen and carbon dioxide. is further broken down into different sections based off altitude

what's the difference between the greenhouse effect, enhanced greenhouse effect and global warming?

greenhouse effect: the natural warming of the Earth due to the greenhouse gases in the environment trapping heat from the sun

enhanced greenhouse effect: the strengthening of the natural greenhouse effect, leading to an increase in greenhouse gases, hence increasing the global average surface temp of Earth (global warming)

global warming: the long-term heating of the earth's surface due to human activities, primarily the burning of fossil fuels

what are the effects of the enhanced greenhouse effect?

1. global warming

2. frequent and extreme weather events

3. rising sea levels

4. ocean acidification

define and give characteristics of the steady state theory

it a cosmological model that proposes that the universe is ageless/infinite (there in no beginning or end), it has and always will look the same, the universe is expanding at a constant rate and the density remains the same

how does the LHC provide evidence for the big bang?

It accelerates particles to speeds close to the speed of light, where the particles are smashed into each other and the debris created during these collisions are studied. these collisions give scientists a glimpse into particles and interactions that may have occurred in the early stages of the universe

what were the first elements formed from the big bang?

Hydrogen and Helium

what is a black hole and how is it formed?

A blackhole is a region in space where the pulling force of gravity is so strong that not even light can escape it. They are formed when stars more than 20x more massive than the sun run out of energy, causing a supernova, leaving behind a black hole

what is a supernova?

A supernova is a powerful explosion caused when a supergiant explodes and then collapses

why is the greenhouse effect important to life on earth?

• the greenhouse gases create a thermal blanket over the Earth

• This traps heat from the sun and prevents it from escaping back into space, keeping the Earth's surface warm enough for life to exist

what's the difference between apparent and absolute magnitude and which is better?

apparent: The apparent magnitude is a measure of how bright a star appears to the observer on Earth and depends on how much light the star emits and the distance between the star and and Earth

absolute:

Absolute magnitude is a measure of the star's actual brightness if the star was 10 parsecs away from earth

absolute magnitude is better because it provides a standarised measure of a star's luminosity by comparing it to a fixed distance of 10 parsecs, compared to apparent magnitude which is dependent on distance

The apparent magnitude is a measure of how bright a star appears to the observer on Earth and depends on how much light the star emits and the distance between the star and and Earth

absolute:

Absolute magnitude is a measure of the star's actual brightness

absolute magnitude is better because it provides a consistent way to compare true brightness of stars while apparent magnitude heavily depends on the location of the observer

how are stars formed?

they are formed from a cloud of dust and hydrogen gas, called a Stella Nebula, where gravity over millions of years causes the dust and gas to spiral together and the particles to move faster until it eventually reaches temps of millions degrees, creating a protostar

explain the life cycle of a small star

• small stars collapse on themselves under their own weight

• - at this point, the star will fuse He atoms to create C to create energy

  - this causes the outer layers of the star to expand, becoming a RED GIANT

  - as the star expands the outer layers will get further away from the middle and the force of gravity will become weaker

  - the star will lose hold of its outer atmosphere and it'll drift off into space and become fuel for nebulas

  - what will remain is the core (dead core), called a WHITE DWARF (dense and hot)

• at this point, the star will fuse He atoms to create C to create energy

• this causes the outer layers of the star to expand, becoming a RED GIANT

• as the star expands the outer layers will get further away from the middle and the force of gravity will become weaker

• the star will lose hold of its outer atmosphere and it'll drift off into space and become fuel for nebulas

• what will remain is the core (dead core), called a WHITE DWARF (dense and hot)

explain the life cycle of a large star

• large stars will continue to fuse heavier elements when the star runs out of H

• it's expand and continue fusing elements up to iron

• will collapse and create a supernova

• after a supernova, the star can leave behind two things; if its mass is 8-20 times more massive than the sun, it'll leave behind a neutron star. if more than 20 times more massive, then will leave behind black hole

what is nuclear fusion?

it's the fusion of two H nuclei to form a He, producing large amounts of energy in the form of light and heat. For it to happen, there must be an immense amount of heat and pressure

what are the two forces acting on stars?

1. the inward force of gravity

2. the outward pressure force caused by nuclear fusion

what is the big bang theory and what are some characteristics?

the big bang theory is one theory into how the universe was created and it describes the universe starting from a small, hot , dense singularity which exploded and then cooled and expanded outwards over the next 13.8 billion years, bringing time and space into existence

what is a singularity?

It's a point in space-time where density and gravity are infinite, causing the breakdown of the laws of physics. They are found at the centre of black holes and according to the big bang theory, a small, hot, dense one created the big bang

what is the doppler effect?

The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It proves that the universe is expanding as light waves become more and more further apart instead of closer together. This is the central hypothesis behind the Big Bang - the universe is expanding from a single point

• It proves that the universe is expanding as light waves become more and more further apart instead of closer together

• This is the central hypothesis behind the Big Bang - the universe is expanding from a single point

what is red shift and blue shift?

When light moves away from us on Earth, red shifting occurs/the frequency becomes lower. When light moves towards us on Earth, blue shifting occurs/the frequency becomes higher

When light moves towards us on Earth, blue shifting occurs/the frequency becomes higher

how does red shifting provide evidence for the big bang?

All galaxies are moving away from Earth/red shifting, the major theory behind the big bang is that the universe is expanding. This proves this.

why are sound waves shortened as they move towards you?

When the object moves towards you, the sound waves are shortened and they get more condensed because there is less space between you and the moving object. This means that we hear it as a high pitch when its coming towards us. When the object moves further away, the waves start to lengthen again due to the increasing amount of distance between you and the object. This means we'll hear it in a lower pitch.

what are the similarities and differences between small and large stars?

similarities:

both luminous spheres of plasma that produce energy through nuclear fusion

differences:

large stars are hotter , brighter and fuse hydrogen much faster = shorter lifespans

small stars are cooler, dimmer and can last billions of years

both luminous spheres of plasma that produce energy through nuclear fusion

differences:

large stars are hotter , brighter and fuse hydrogen much faster = shorter lifespans

small stars are cooler, dimmer and can last billions of years

how do protostars form mature stars?

• protostars have not yet produced heat or light

- it will collapse from its own gravity

- causes the centre of the cloud to heat up, creating immense pressure in the core so that the atoms in the core fuse together thru nuclear reactions

- it's this hot core that is the beginning of a star

• it will collapse from its own gravity

• causes the centre of the cloud to heat up, creating immense pressure in the core so that the atoms in the core fuse together thru nuclear reactions

• it's this hot core that is the beginning of a star

what is a carbon sink and what are 2 examples

Any place that absorbs more carbon than it releases is known as a carbon sink eg.

Amazon rainforest, oceans

what is a carbon source?

Any process that releases more carbon than it absorbs is known as a carbon source ie. Fossil fuels, cattle farming

what is ocean acidification

ocean acidification refers to a reduction in the PH of the ocean over an extended period of time, primarily caused by an uptake of CO2 in the atmosphere

when CO2 is absorbed by seawater, chemical reactions occur, resulting in an increase of hydrogen ions. this causes the ocean to become more acidic and for carbonate ions to become less abundant

carbonate ions are important as they help calcifying animals build/maintain their shells (oysters, clams) so a lack of them affect these animals. also, some fish ability to detect predators is decreased in acidic waters, causing the entire food web to be at risk

how does the carbon cycle work?

1. Nitrogen 14 isotope comes in contact with Earth's atmosphere and turns into Carbon 14

2. Plants use CO2 in photosynthesis

3. Animals eat plants

4. Animals and plants die, where their remains decompose into the Earth

5. Decomposing animals and plants turn into fossil fuels in the form of oil (and diamonds)

6. These fossil fuels get used by factories which release CO2 into the atmosphere

7. This CO2 is absorbed into the ocean

8. More CO2 in the ocean will lower the PH level of the ocean/make it more acidic

9. This means that there is less calcium carbonate, making it harder for shelled creatures to create/maintain their shells. This will impact the food chain too as animals that rely on calcifying animals for food will suffer