Earth, stars, galaxies and space Flashcards Preview

Physics (Elliott) > Earth, stars, galaxies and space > Flashcards

Flashcards in Earth, stars, galaxies and space Deck (96):
1

what is the diameter of earth?

The diameter of the Earth is 12,800km (7,953 miles)

2

how many times bigger is the sun than the earth?

the diameter of the Sun is 109 times that of the Earth’s

3

how far is the earth from the sun?

The Earth is 150 million km (93 million miles) from the Sun

4

how far away is the closest star?

The distance to the nearest star is four light years.

5

What is the source of the Sun's energy?

Nuclear fusion

6

Which is a method of measuring the distance to stars?

Parallax

7

How old is the Universe?

14000 million years old

8

what was the main evidence for Wegener's theory of continental drift?

Continents seem to fit together

9

What causes seafloor spreading?

Movement in the solid mantle

10

Where are volcanoes and earthquakes likely to happen?

At the edge of tectonic plates

11

Which is evidence for seafloor spreading?

Magnetic stripes on the seafloor

12

The vibrations detected from the site of an earthquake are called...

seismic waves

13

What are the layers in the Earth, starting from the middle?

Core, mantle, crust

14

What is the unit of wave frequency?

Hertz, Hz

15

what is the formula for wave speed?

wave length (m) x frequency (Hz) = wave speed (m/s)

16

Which type(s) of wave can be detected on the other side of the Earth from an earthquake

P waves

17

what is a P wave?

I wave that travels like a worm and shakes the ground up and down

18

what is an S wave

a wave that travels like a whip lash and shakes the ground side to side.

19

which is more destructive towards buildings, P waves or S waves? and why?

S waves. because building are designed to withstand up and down motion, not side to side motion.

20

The Earth is one of the.............planets orbiting the Sun, and there are many other members of the Solar System including ............, moons and ........... Data provides the answers to many questions on this subject, but some questions remain unanswered.

The Earth is one of the eight planets orbiting the Sun, and there are many other members of the Solar System including asteroids, moons and planets. Data provides the answers to many questions on this subject, but some questions remain unanswered.

21

The Universe is considered to be ..............there is, though most of it is thought to be ...........

The Universe is considered to be everything there is, though most of it is thought to be empty.

22

Much is now known about the Earth and the place of the Earth in the Universe, for example:
the diameter of the Earth is 12,800km (7,953 miles)
the diameter of the Sun is ........ times that of the Earth’s
the Earth is .......................... from the Sun
the distance to the nearest star is ........... .........
years.

Much is now known about the Earth and the place of the Earth in the Universe, for example:
the diameter of the Earth is 12,800km (7,953 miles)
the diameter of the Sun is 109 times that of the Earth’s
the Earth is 150 million km (93 million miles) from the Sun
the distance to the nearest star is four light years.

23

asteroids are much smaller than planets, and ........ the Sun. Most of the asteroids are between .......................... and J..........r, but some come close to the Earth. Our Moon is nearly .............. of the diameter of the Earth
............ have different ........to those of planets, spending much of their orbital time far from the Sun. Comets are similar in size to asteroids, but are made of .... and ...... The ........when the comet approaches the Sun, and forms the ........ ............

asteroids are much smaller than planets, and orbit the Sun. Most of the asteroids are between the planets Mars and Jupiter, but some come close to the Earth
moons orbit planets. Most are tiny. Only a few are as large as our Moon, which is nearly a sixth of the diameter of the Earth
comets have different orbits to those of planets, spending much of their orbital time far from the Sun. Comets are similar in size to asteroids, but are made of dust and ice. The ice melts when the comet approaches the Sun, and forms the comet’s tail.

24

Nearly all of the mass in our Solar System is in the ........

Nearly all of the mass in our Solar System is in the Sun.

25

In stars larger than our ..... helium ..........can be fused together to create larger .......... nuclei. As the Earth contains many of these larger ..........., like carbon, ............, ......., etc, scientists believe that our Solar System was made from the ................ of an earlier ........

In stars larger than our Sun helium nuclei can be fused together to create larger atomic nuclei. As the Earth contains many of these larger atoms, like carbon, oxygen, iron, etc, scientists believe that our Solar System was made from the remains of an earlier star.

26

what can be fused together to create larger atomic nuclei.

In stars larger than our Sun helium nuclei can be fused together to create larger atomic nuclei.

27

As the gas falls together, it gets ..... A star forms when it is ... enough for a ...... The Sun is very large. Its diameter is ..... times the Earth's. The Sun is the source of nearly all the energy we receive. For many years, it was a mystery as to where this came from and this baffled the leading scientists. It is now understood that the......... ................is the energy source. In ................ .............. smaller nuclei come together and form ..............nuclei. For example ............ ...........are joined together to make ............ ............ This releases enormous amounts of energy. . reaction to start. This releases ....... , and keeps the star .... The outward pressure from the ............ hot ............is balanced by the force of the star's ............. This happened about ............years ago. This is quite recent in the history of the Universe, which is currently believed to be ............years old.

How stars and planets are formed:
As the gas falls together, it gets hot. A star forms when it is hot enough for a nuclear fusion reaction to start. This releases energy, and keeps the star hot. The outward pressure from the expanding hot gases is balanced by the force of the star's gravity. This happened about 5 billion years ago. This is quite recent in the history of the Universe, which is currently believed to be 14 billion years old.

28

The............that distant stars and galaxies produce gives us information about the d............ to stars, and about how they are ............. In the future, this may allow us to find out if life exists on planets around some of these stars.


The radiation that distant stars and galaxies produce gives us information about the distances to stars, and about how they are changing. In the future, this may allow us to find out if life exists on planets around some of these stars.

29

Powerful telescopes allowed astronomers to answer a question that had baffled scientists since the astronomer ............ (1473-1543) first suggested that the Earth moved ............. If the Earth moves, you would expect to see a different view of the stars at different times of the year, in the same way as the room you are in looks slightly different if you move your head to one side. That is to say everything seems to move in the opposite direction to your head, but the objects close to you seem to move more. This effect is called .............

Powerful telescopes allowed astronomers to answer a question that had baffled scientists since the astronomer Copernicus (1473-1543) first suggested that the Earth moved around the Sun. If the Earth moves, you would expect to see a different view of the stars at different times of the year, in the same way as the room you are in looks slightly different if you move your head to one side. That is to say everything seems to move in the opposite direction to your head, but the objects close to you seem to move more. This effect is called parallax.

30

So if the Earth was moving, why did the stars always look the same?

The answer to the question was revealed by more powerful telescopes. These showed that nearby stars do seem to move from side to side and back every year when compared with very distant stars, but that the amount of movement is tiny.

31

Telescopes in space, such as the ..................Space Telescope, can observe the whole sky. They are above light pollution and above dust and clouds in the atmosphere. What are the disadvantages? .

However, they are difficult and expensive to launch and maintain. If anything goes wrong, only astronauts can fix them.

32

What is a light-year ?

A light-year is the distance light travels in a year. Light travels very fast (300,000 km/186,282 miles per second), and takes only about eight minutes to reach us from the Sun. It takes over four years to reach us from the next nearest star (Proxima Centauri), and 100,000 years to cross the Milky Way galaxy. We say that the distance to the next nearest star is four lightyears, and the diameter of the Milky Way is 100,000 light years.

33

When initial distances to stars were being established more than one method was employed. After establishing distances of nearby stars using the parallax method, what other method was used?

After establishing distances of nearby stars using the parallax method, the 'brightness method' was used to approximate distances to further stars. Other methods were also used.

34

What is the assumptions with the parallax method ?

with the parallax method an assumption made is that during the total time in which the measurement is taking place, distance remains constant between the two stars.

35

What explanations can be developed to illustrate the theory that the dinosaurs were destroyed by an asteroid impact?

asteroids are small objects orbiting the Sun
some asteroids have orbits close to the Earth
the dinosaurs died out at about the same time as a large crater was made in Mexico.

Data statements tell you facts, and may contain measurements.

Explanations seek to explain the data, and formulating an explanation requires imagination and creativity. One explanation is that an asteroid collision may have killed off the dinosaurs. The asteroid impact would have created dust that blocked out light and heat from the Sun.

36

A good explanation will explain data, and link together things thatwere not thought to be related. What else should it make ? Use this in relation to the extinction theory of dinasours
asteroids often contain the rare metal iridium - data
a huge asteroid impact would send iridium dust throughout the world - prediction
sedimentary rocks from the time the dinosaurs died out contain iridium - data
when the asteroid crashed, the iridium came from the dust tha tblocked out the Sun - explanation.

Predictions

A good explanation will explain data, and link together things thatwere not thought to be related. It should also make predictions.
asteroids often contain the rare metal iridium - data
a huge asteroid impact would send iridium dust throughout the world - prediction
sedimentary rocks from the time the dinosaurs died out contain iridium - data
when the asteroid crashed, the iridium came from the dust tha tblocked out the Sun - explanation.

37

The asteroid theory is not the only one about the death of the dinosaurs. Others are what?

The asteroid theory is not the only one about the death of the dinosaurs. Other are:
there were huge volcanic eruptions in India at the time the dinosaurs died out - data
big volcanic eruptions cause dust clouds thatblock out the Sun - data
the big Indian eruptions could have killed out the dinosaurs by cooling the Earth - explanation

38

Not all scientific questions have answers at this time. For some of the questions there is not enough data yet. What is an example of this question? And give an example of a questions, where there may never be the data you need?

is there life on distant planets? For other questions, there may never be the data you need. An example of this is: what happened before the ‘Big Bang’ when the Universe was created?

39

List 4 things you know about Galaxies?

1) Galaxies contain thousands of millions of stars.
2) For many years, it was thought that our galaxy, which is the Milky Way, was the only one that existed, and that the blurry nebulae that could be seen were clouds of dust and gas in the Milky Way.
3) Observations of many of these nebulae by astronomers such as Edwin Hubble showed they were in fact galaxies outside the Milky Way
4) and that distant galaxies are all moving away from us.

40

Whose observations led to the ‘Big Bang’ explanation of the beginning of the Universe? What date did it set this at ?

Hubble’s observations led to the ‘Big Bang’ explanation of the beginning of the Universe, and set a date for this at 14,000 million years ago.

41

What is believed to be the future of the Universe ?

the Universe will continue to expand in the way it is at the moment. Perhaps gravity will eventually win and pull all the fleeing galaxies back together again. Better observations of very distant galaxies and a better understanding of the mysterious ‘dark matter’ are needed before these will be understood.

42

The astronomer Edwin Hubble (1889-1953) did what? What did he find?

The astronomer Edwin Hubble (1889-1953) measured the distance to many galaxies, and also the speeds with which they are moving away from us. He found a strong correlation between these factors.

43

What correlation is summed up in Hubble’s Law?

This correlation is summed up in Hubble’s Law which says that the speed at which a galaxy moves away from us is proportional to its distance from us.

The causal link which explains this law is that space itself is expanding.

As the Universe expands, galaxies that are already further apart will increase in separation even more, and so move away at higher speeds

44

What is red-shift?

The development of powerful telescopes allowed astronomers to see distant galaxies. The light observed was shifted towards the red end of the spectrum. This phenomenon is known as red-shift. The degree to which light has been shifted indicates how fast the galaxies are moving away

45

what are P-waves (P stands for primary)?

P-waves (P stands for primary) arrive at the detector first. They are longitudinal waves which mean the vibrations are along the same direction as the direction of travel.

46

Other examples of longitudinal waves are?

Other examples of longitudinal waves include sound waves and waves in a stretched spring.

47

What is Amplitude?

As waves travel, they set up patterns of disturbance. The amplitude of a wave is its maximum disturbance from its undisturbed position. Take care: the amplitude is not the distance between the top and bottom of a wave. It is the distance from the middle to the top.

48

What is a Wavelength?

The wavelength of a wave is the distance between a point on one wave and the same point on the next wave. It is often easiest to measure this from the crest of one wave to the crest of the next wave, but it doesn't matter where as long as it is the same point in each wave

49

What is the frequency of a wave ?

The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second. The unit of frequency is the hertz (Hz). It is common for kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) to be used when waves have very high frequencies. For example, most people cannot hear a high-pitched sound above 20kHz, radio stations broadcast radio waves with frequencies of about 100MHz, while most wireless computer networks operate at 2.4GHz.

50

The distance travelled by a wave is calculated using this what equation?

The distance travelled by a wave is calculated using this equation:

Distance = speed x time

51

What is the equation for wave speed?


wave speed = frequency x wavelength

wave speed = frequency x wavelength

For example, a wave with a frequency of 100Hz and a wavelength of 2m travels at 100 x 2 = 200m/s.

The speed of a wave does not usually depend on its frequency or its amplitude.

52

How old is the Earth? When is there evidence that living things existed on Earth ?

the Earth is about 4,500 million years old
there is evidence that living things existed on Earth at least 3,500 million years ago
no one was there to record how life began

53

What is the main theory about how life on earth began?

Through the study of simple organisms and the chemistry of living things, we can develop scientific theories about how life on Earth began. The main theory is that living things developed from molecules that could replicate, or copy, themselves, rather like DNA does.

There are two possible origins for these replicating molecules:
they were produced by the conditions on Earth at the time
they came from somewhere else, such as another planet in our Solar System, or further out in space.

Over many millions of years these molecules joined with other molecules, becoming gradually more complex and dependent on each other. The process of evolution by natural selection eventually led to all of the different living things that we see on Earth today.

54

How did molecules become more complex ?

Over many millions of years these molecules joined with other molecules, becoming gradually more complex and dependent on each other. The process of evolution by natural selection eventually led to all of the different living things that we see on Earth today.

55

Who was Charles Darwin?

Charles Darwin was an English naturalist who studied variation in plants and animals during a five-year voyage around the world in the 19th century. He explained his ideas on evolution in a book called, 'On the Origin of Species', published in 1859.

56

What is the basic idea behind the theory of evolution?

The basic idea behind the theory of evolution is that all the different species have evolved from simple life forms. These simple life forms first developed more than 3 billion years ago (the Earth is about 4.5 billion years old). The timeline below shows some of the key events in the evolution of life on Earth, from the first bacteria to the first modern humans.

57

What is Natural selection?

The theory of evolution states that evolution happens by natural selection. The key points are that:
individuals in a species show a wide range of variation
this variation is because of differences in their genes
individuals with characteristics most suited to the environment are more likely to survive and reproduce
the genes that allow these individuals to be successful are passed to their offspring.

58

What can variation be caused by?

You need to remember that variation can be caused by both genes and the environment. But it is only variation caused by genes that can be passed on to the next generation.

59

In Darwin's theory, what sort of variation can be passed on to the next generation.?

You need to remember that variation can be caused by both genes and the environment. But it is only variation caused by genes that can be passed on to the next generation.

60

What have Farmers used selective breeding for?

Farmers have used selective breeding for centuries to increase milk yield in cattle, produce larger eggs from chickens and obtain more grain from wheat.

61

What are Mutations ?

Mutations are changes that can occur in genes. These changes are random and can be caused by background radiation and chemicals that we come into contact with, for example the chemicals in cigarette smoke.

62

What happens with a mutuation?

Sometimes these changes can be so severe that the cell dies, sometimes the cell can divide uncontrollably and become cancerous, and sometimes the changes are small and the cell survives. Very rarely the changes may even be beneficial to us and produce new and useful characteristics.

63

When are mutations passed on ?

Passing on mutations

If these changes occur in normal body cells, the changes are lost when we die. But if the changes occur in our sex cells such as sperm and ova, there is the possibility that the changes in the gene will be passed onto the next generation.

It is when these changes are passed on to the next generation that natural selection can either ensure that they are selected if they are useful, or disappear from the gene pool if they are not

64

What causes a new species to be created?

The combined effect of these mutations, environmental changes, and natural selection, can sometimes produce changes in the organism that are so great that a new species is produced. This does not happen very often and only occurs when the mutated organism can no longer breed with the original species and is capable of producing fertile offspring

65

Darwin was not the only person to develop a theory of evolution. Who else did ?

Jean-Baptiste Lamarck was a French scientist who developed an alternative theory at the beginning of the 19th century. His theory involved two ideas. These are:
the law of use and disuse
the law of inheritance of acquired characteristics.

66

Lamarck's theory cannot account for all the observations made about life on Earth.what couldn't it account for?

Lamarck's theory cannot account for all the observations made about life on Earth. For instance, his theory would predict that all organisms gradually become complex, and simple organisms disappear.

Darwin's theory can account for the continued presence of simple organisms.

67

what is the story of the Peppered moths?

Before the Industrial Revolution in Britain, most peppered moths were of the pale variety. They were camouflaged against the pale birch trees they rested on. Moths with a mutant black colouring were spotted easily by birds and eaten. This gave the white variety an advantage, making them more likely to survive and reproduce.

Airborne pollution in industrial areas blackened the birch tree bark with soot. This meant the mutant black moths were now camouflaged, while the white variety became more vulnerable to predators. It gave the black variety an advantage. They were then more likely to survive and reproduce. Over time, the black peppered moths became far more numerous in urban areas than the pale variety.

68

How does DNA support the theory of evolution?

Scientists can now examine the DNA from different species of organism and use the data produced to see how closely related the two species are to each other. By collecting a lot of this data, scientists can compare the results with conventional ideas about how organisms have evolved. What they found was that DNA data supported the conventional theory of evolution.

69

what did Darwin notice on the Galapagos ?

Darwin noticed that different islands in the Galapagos had different types of finches adapted to eating the type of food found on each island. It was only when Darwin produced his theory of evolution by natural selection that these two unrelated facts were linked together.

70

The Sun is very large. Its diameter is ..... times the Earth's. The Sun is the source of nearly all the energy we receive.

The Sun is very large. Its diameter is 109 times the Earth's.

71

What is the energy source of the sun? How does it create energy?

It is now understood that the nuclear fusion is the energy source. In nuclear fusion, smaller nuclei come together and form larger nuclei. For example hydrogen nuclei are joined together to make helium nuclei. This releases enormous amounts of energy.

72

Why is a certain level of uncertainty found in the results?

As methods were reliant on each other, a certain level of uncertainty is found in the results.

73

What is understood about the beginning and end of the Universe?

There are many questions left unanswered about the beginning and end of the Universe. Observations suggest it contains a lot of ‘dark matter’ that cannot be seen, and this is not yet clearly understood.

74

What was early Earth like?

early Earth was hotter and the atmosphere consisted mostly of carbon dioxide (with other gases such as ammonia and methane).

75

Everything we know about stars and galaxies has come from what>

Everything we know about stars and galaxies has come from the light, and other radiations, that they give out. This has become more difficult to see from the Earth’s surface, as light pollution from towns and cities interferes with observations of the night sky.


76

What are nebulae ?

Looking at the sky with the naked eye shows the Sun, Moon, stars, planets and a few cloudy patches called nebulae. When telescopes were invented and developed, astronomers could see that some of the nebulae were in fact groups of millions of stars. These are galaxies.

77

The Earth is just one of how many planets orbiting the Sun, which is a ? . The orbits all lie in the same plane, and the planets all go round in the same direction.

There are many other members of our Solar System:
asteroids are much smaller than planets, and orbit the Sun. Most of the asteroids are between the planets Mars and Jupiter, but some come close to the Earth
moons orbit planets. Most are tiny. Only a few are as large as our Moon, which is nearly a sixth of the diameter of the Earth
comets have different orbits to those of planets, spending much of their orbital time far from the Sun. Comets are similar in size to asteroids, but are made of dust and ice. The ice melts when the comet approaches the Sun, and forms the comet’s tail.

The Earth is just one of the eight planets orbiting the Sun, which is a star.

78

Do the orbits all lie in the same plane? and go round in the same direction?

The orbits all lie in the same plane, and the planets all go round in the same direction.

79



There are many other members of our Solar System - what are they?

asteroids are much smaller than planets, and orbit the Sun. Most of the asteroids are between the planets Mars and Jupiter, but some come close to the Earth
moons orbit planets. Most are tiny. Only a few are as large as our Moon, which is nearly a sixth of the diameter of the Earth
comets have different orbits to those of planets, spending much of their orbital time far from the Sun. Comets are similar in size to asteroids, but are made of dust and ice.

80

What forms the comets tail?

The ice melts when the comet approaches the Sun, and forms the comet’s tail.

81

Nearly all of the mass in our Solar System is in the what? .

Nearly all of the mass in our Solar System is in the Sun.

82

The sun is the source of nearly all energy we receive. What is the source of the sun's energy ?

It is now understood that the nuclear fusion is the energy source. In nuclear fusion, smaller nuclei come together and form larger nuclei. For example hydrogen nuclei are joined together to make helium nuclei. This releases enormous amounts of energy.
hydrogen nucleus + hydrogen nucleus → helium nuclei

83

why do scientists think that our planet was made from the remains of an earlier star?

In stars larger than our Sun helium nuclei can be fused together to create larger atomic nuclei. As the Earth contains many of these larger atoms, like carbon, oxygen, iron, etc, scientists believe that our Solar System was made from the remains of an earlier star.

84

What is sun is the diameter of the sun compared to earth?

he Sun is very large. Its diameter is 109 times the Earth's.

85



the diameter of the Earth is ?



the diameter of the Earth is 12,800km (7,953 miles)

86

the diameter of the Sun is ?


the diameter of the Sun is 109 times that of the Earth’s

87




the Earth is how far from the Sun?

the Earth is 150 million km (93 million miles) from the Sun

88

the distance to the nearest star is>

the distance to the nearest star is four light years.

89

Rocks provide evidence for changes in the Earth. Who presented his idea of a rock cycle to the Royal Society and when? What were his ideas?

In 1785 James Hutton presented his idea of a rock cycle to the Royal Society. He detailed ideas of erosion and sedimentation taking place over long periods of time, making massive changes to the Earth’s surface.

90

What makes massive changes to the earth's surface?

He detailed ideas of erosion and sedimentation taking place over long periods of time, making massive changes to the Earth’s surface.

91

Geologists can use other evidence from the rocks themselves such as:

looking at cross-cutting features
using fossils
deepness of the rock (younger rocks are usually on top of older ones).

92

what are cross-cutting features? (rock that cuts across another is younger)

rock that cuts across another is younger)

93

How do you get evidence that is more accurate about the age of rocks

radioactive dating

94

When the magma oozing out of mid-ocean ridges solidifies into rock, the rock records what?

The typical speed of seafloor spreading is slow: about 10 cm per year. When the magma oozing out of mid-ocean ridges solidifies into rock, the rock records the direction of the Earth’s magnetic field. The Earth’s magnetic field changes with time, and sometimes even reverses its direction. These changes are recorded in the rocks. The same magnetic patterns are seen on both sides of the mid-ocean ridges.

95

Magnetic changes are recorded in the rock. What happens to the Earth’s magnetic field with time?

The Earth’s magnetic field changes with time, and sometimes even reverses its direction. These changes are recorded in the rocks.

96

Are the same magnetic patterns seen on both sides of the mid-ocean ridges?

yes