Astronomy Flashcards

1
Q

What is the order of the planets from the sun?

A
  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
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2
Q

What is a moon?

A

A natural satellite that orbits a planet

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3
Q

What is a protostar?

A

Where nuclear fusion begins to form a star, hydrogen atoms fuse to form helium

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4
Q

Describe the life cycle of a star like our sun

A
  • Cloud of dust forms called a nebula
  • Then it becomes a protostar, and nuclear fusion begins
  • Nuclear fusion leads to it being a main sequence star
  • Nuclear fusion goes on until it becomes a red giant
  • When fusion stops, the star will become a white dwarf
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5
Q

Describe the life cycle of a massive star

A
  • Cloud of dust forms called a nebula
  • Then it becomes a protostar, and nuclear fusion begins
  • Nuclear fusion leads to it being a main sequence star
  • Nuclear fusion goes on until it expands to become a red super giant
  • When nuclear fusion stops a supernova will happen
  • It will then become a neutron star or a black hole
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6
Q

What is an asteroid?

A

A small object composed of metal and rock that follows an elliptical orbit around its sun

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7
Q

What is a comet?

A

A small object composed of rock, dust and ice that follows an elliptical orbit around its sun

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8
Q

Other than what it’s made up of, what is different between a comet and an asteroid?

A

Comets begin to vaporise as they approach a star, turning it into gas which forms a distinctive tail

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9
Q

Describe the relationship between the weight of an object and the gravitational field strength

A

They are directly proportional

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10
Q

Describe the speed and velocity for things that follow circular orbits

A

The speed stays the same but the velocity changes due to gravity

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11
Q

How does the balance of thermal expansion and gravity affect the lifecycle of stars?

A
  • Smaller stars have longer lives due to smaller forces of gravity, that are easier to balance
  • Larger stars have shorter lives due to larger forces of gravity, that are more difficult to balance
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12
Q

Why is the gravitational field strength different for other bodies in space?

A

They have different masses

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13
Q

Why is a person’s weight different on a different planet?

A

Because the gravitational field strength is different

W = mg

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14
Q

What is a dwarf planet?

A

A body is space unable to clear its neighbourhood (meaning other things could be in the same orbit)

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15
Q

How have ideas about the structure of the solar system changed over time?

A

For a long time people believed in the geocentric model, with Earth in the centre and The Sun and planets orbiting around it

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16
Q

Do satellites in a circular orbit maintain a constant speed?

A

Yes

17
Q

Do satellites in a circular orbit maintain a constant velocity?

A

No, due to changing direction

18
Q

What do planets orbit?

A

A barycentre, the common centre of mass of itself and the star

19
Q

What type of orbit does a planet follow?

A

Circular

20
Q

What type of orbit does a moon follow?

A

Circular

21
Q

What type of orbit does a comet follow?

A

Elliptical

22
Q

What type of orbit do artificial satellites follow?

A

Circular

23
Q

What happens if the speed of a satellite increases in a stable orbit?

A

The radius of the orbit will increase

24
Q

What is redshift?

A

The increase in wavelength of light from objects moving away from Earth

25
Q

What causes redshift?

A

The Doppler Effect

26
Q

What does CMBR stand for?

A

Cosmic Microwave Background Radiation

27
Q

How does CMBR prove the Big Bang theory?

A
  • In 1948 microwave radiation was discovered across the sky (CMBR)
  • According to the Big Bang theory, huge amounts of radiation was released during the Big Bang
  • CMBR is the radiation left over from the explosion
28
Q

What is the Big Bang theory?

A

The idea that the universe is constantly expanding and all matter was created in the Big Bang

29
Q

What is the Steady State theory?

A

The idea that the universe has always existed and is constantly expanding and matter is also constantly being created

30
Q

Which model for the origin of the universe is currently accepted and why?

A

The Big Bang theory because there is more evidence to support it

31
Q

What evidence is there to support the Big Bang theory?

A
  • Redshift
  • CMBR
32
Q

What evidence is there to support the Steady State theory?

A

Redshift

33
Q

What does redshift prove about the universe?

A

It is constantly expanding

34
Q

How does redshift prove that the universe is expanding?

A

Light from most stars has a higher wavelength (shifted to red), which means the universe is expanding, proven by the doppler effect.

35
Q

What happens if a wave source is moving relative to an observer?

A

There will be a change in the observed frequency and wavelength

36
Q

The further light is redshifted…

A

…the faster the object is moving away from us

37
Q

Why doesn’t CMBR support the steady state theory?

A

According to the Steady State theory, the universe has always existed, therefore there can be no radiation emitted from an explosion that created the universe

38
Q

Why are some telescopes are located outside the Earth’s atmosphere?

A

Because the atmosphere distorts the vision

39
Q

How have methods of observing the Universe have changed over time?

A
  • Originally people could only observe with the naked eye
  • Telescopes were then invented allowing people see clearly into space
  • Over time telescopes have become more powerful and some are positioned in space