Topic #1

Question 1

What did Aristotle believe?

(2 points)

Answer 1

• Geocentric Universe
• Movement of planets and stars were perfect and circular

Question 2

What is gravity?

Answer 2

The tendancy of earth and water to sink

Question 3

What is levity?

Answer 3

The tendancy of air and fire to rise

Question 4

What is geocentric?

Copernican system

Answer 4

Everything in the solar system revoleved around the earth

Question 5

What did Copernicus believe?

(2 points)

Answer 5

• Heliocentric model
• Earth roated on an axis

Question 6

What did Galileo do?

(3 points)

Answer 6

• Built a telescope to look at the moon
• Challenegd the belief that the celestial bodies were perfect spheres
• Confirmed the Copernican model

Question 7

What is heliocentric?

Ptolemaic system

Answer 7

Everything in the solar system revolved around the sun

Question 8

What did Johannes Kepler believe?

Answer 8

He believed in eliptical orbits

explained strange apparent movements of the planets

Question 9

What is a planet?

Answer 9

An astronomical body that is big enough to be rounded by its own gravity

Question 10

What is a super cluster?

Answer 10

A collection of more than a million galaxies

Question 11

What is Hubble’s law?

Answer 11

Hubble’s Law states that the rate at which galaxies move apart from each other is proportional to their
distance from each other.

In other words – the greater the
distance between any two
galaxies, the faster they are moving apart

Question 12

What is the steady state theory?

Answer 12

The Universe has always existed and always will –
that the Universe has no beginning and no end

Question 13

What evidence shows the big bang theory happened?

(4 points)

Answer 13

• Red shift/movement of celestial bodies
• Cosmic microwave background radiation
• Proportion of elements in the Universe (H, He)
• Expansion of the Universe

Question 14

What is the doppler effect?

Answer 14

Objects moving away from Earth have their absorption lines shifted towards the red end of the spectrum.

Question 15

What is redshift?

Answer 15

• As the galaxies move away from Earth, the wavelength of that light that it
  emits get longer (stretched out).
• Longer wavelengths of visible light are red
• Shorter wavelengths of visible light are blue

Question 16

What is the electromagnetic spectrum?

Answer 16

Term used by scientists to describe the entire range of light that exists

Question 17

What is ionising radaition?

Answer 17

The waves are so small that they can interact with cells, DNA and atoms.

Question 18

How can we tell the distance of a galaxy/star from us?

Answer 18

Absorption Spectrum

analysing the red shift

Question 19

What is the angle of incidence?

Answer 19

The light directly from the light source

Question 20

How do you meaure the focal length?

Answer 20

Measure the distance from the intersection of the reflected/refracted lights to the mirror

Question 21

What is the virtual focal length?

Answer 21

Measure the distance from the intersection of the light that has been reflected/refracted on the same course pass the mirror

Question 22

What is field of vision?

Answer 22

Near objects fill more of our field vision and far objects fill our field vision less

Question 23

What are reflecting telescopes?

Answer 23

Concave mirrors are used in reflecting telescopes to gather light and then focus and reflect the rays onto a flat mirror and then towards an eyepiece.

Question 24

What is refraction?

(3 points)

Answer 24

• When light travels from one substance into another that is transparent or translucent, it can slow down or speed up.
• Refraction causes light to change direction or bend.
• This change in speed as light travels from one substance to another is called
  refraction.

Question 25

What are the two types of lens?

Answer 25

Biconvex lens Biconcave lens

Question 26

What is a star? | (3 points)

Answer 26

- A luminous (light emitting) ball of gas. - Mainly made up oh Hydrogen and Helium, held together by its own gravity. - Has nuclear fusion in the core that produces heat and a small amount of heavier elements.

Question 27

How do stars form?

Answer 27

- Due to the intense density, the particles towards the centre begin to attract to each other, due to gravitational pull. - The material begins to heat up, causing a hot core. - The material continues to spin. - This forms a protostar (when fusion begins, but is not stable), which will eventually become a star, after it has broken away from the main cloud.

Question 28

What is nuclear fusion?

Answer 28

Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy.

Question 29

What is Stellar nucleosynthesis?

Answer 29

Stellar nucleosynthesis is the creation of elements through nuclear fusion within stars. The extreme heat and pressure of the star push elements together to the point where the nuclei in their atoms fuse, creating new elements.

Question 30

What happens at the Stellar Nebula stage? | 1st stage

Answer 30

- A star begins its life as a "stellar nebula," which is a big cloud of gas and dust in space. - Gravity causes the nebula to collapse, and it becomes denser and hotter. - As the cloud contracts, it forms a "protostar," a hot and dense core.

Question 31

What happens at the main sequence stage? | 2nd step

Answer 31

- When the protostar's core becomes hot enough, nuclear fusion starts. - The protostar transforms into a "main sequence star," where it shines brightly and steadily. ## Footnote Nuclear fusion is when hydrogen atoms fuse together to create helium, releasing energy.

Question 32

What happens at the red giant stage? | 3rd stage

Answer 32

- As the star ages and runs out of hydrogen fuel, its core contracts and outer layers expand. - This expansion turns the star into a "red giant," larger and redder than before. - During this stage, the star's brightness and size increase significantly.

Question 33

What happens at planetary nebula stage? | 4th stage

Answer 33

- When the helium fuel is depleted, the outer layers of the star are ejected into space. - The ejected material forms a glowing shell called a "planetary nebula." - The core that remains in the center is called a "white dwarf."

Question 34

What happens at the white dwarf stage? | 5th stage

Answer 34

- The star's core, the white dwarf, is very dense and compact but no longer undergoes fusion. - It slowly cools down over billions of years, becoming a "black dwarf" when it no longer emits light.

Question 35

What happens at the Supernova stage (massive stars only)? | 6th step

Answer 35

- If the star is much larger, it undergoes a dramatic explosion called a "supernova." - A supernova releases an enormous amount of energy and can outshine an entire galaxy for a short time. - After the explosion, what remains can become a neutron star or even a black hole.

Question 36

What is nuclear fusion?

Answer 36

small atoms, like hydrogen, combine to create bigger atoms, like helium, while releasing a lot of energy. It keeps the stars releasing energy to stay hot and bright.

Question 37

What is atmospheric opacity and whendoes it allow radiation to pass through?

Answer 37

**When the atmosphere is not very opaque:** - It lets a lot of radiation (like light) pass through. Telescopes and satellites can see objects in space clearly because there is not much interference. **When the atmosphere is more opaque:** - It blocks or absorbs more radiation. - This makes it harder to see certain objects in space, especially if they emit certain types of radiation.

Question 38

What is the difference between reflection and refraction?

Answer 38

**reflection** is when light bounces off a surface like a mirror, and **refraction** is when light bends as it passes from one material to another,