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Flashcards in Naked eye astronomy Deck (34):
1

Observations of the Sun, Moon, nearby planets and stars can tell us a lot about what?

any celestial bodies and phenomena can be observed without specialist equipment. Observations of the Sun, Moon, nearby planets and stars can tell us a lot about the nature and movement of objects in the solar system and beyond.

2

which planets can be seen with the naked eye?

The nearest planets can be seen with the naked eye. They are Mercury, Venus, Mars, Saturn and Jupiter.

3

what is retrograde motion?

The planets sometimes appear to move with retrograde motion. This is when the planets appear to slow down or go in reverse, relative to the positions of distant 'fixed' stars.

4

what is the sun's movement across the sky?

The Sun rises in the east and sets in the west, moving across the sky during the day.

5

How long does It take the Sun to move from its highest points to its next highest point ?

It takes 24 hours for the Sun to move from its highest point in the sky (at noon) back to its highest point the following day.

6

How long does it take the stars to move across the sky from east to west?

The stars to move across the sky from east to west, but they take slightly less than 24 hours. The Moon takes slightly longer than 24 hours to apparently move across the sky in the same direction.

7

How long does The Moon takes to apparently move across the sky in the same direction east to west ?

The Moon takes slightly longer than 24 hours to apparently move across the sky in the same direction.

8

why will different stars be visible from a position on Earth at different times of the year?

Because the Earth orbits the Sun, different stars will be visible from a position on Earth at different times of the year.

9

Phases of the Moon - what is the linear cycle?

The Moon’s appearance changes during its 28-day orbit of the Earth. This is called the lunar cycle. This can be explained by considering the way that sunlight falls on the moon as it changes its position around the Earth.

10

what is a new moon.

When the Sun is effectively behind the Moon, the side of the Moon that faces the Earth is in shadow - this is called a new moon.

11

what is full moon

When the side of the Moon that faces the Earth is fully illuminated by the Sun, this is called a full moon

12

what is a Solar eclipse?

A solar eclipse happens when the Moon passes directly between the Sun and the Earth - on the same line - casting a shadow of the Moon on the surface of the Earth. This would happen during the new moon phase of the lunar cycle.

13

what is a total eclipse?

If the Moon completely obscures the Sun (when viewed from Earth), it is called a total eclipse.

14

what is a partial eclipse?

If the Moon partially obscures the Sun, it is a partial eclipse.

15

Why is vViewing solar eclipses with the naked eye very dangerous – it can burn your retina and lead to permanent damage to your eye.

it can burn your retina and lead to permanent damage to your eye.

16

what is a safe way to look towards the sun ?

a safe way to look towards the sun is to use a pinhole viewer. If you make one do not look through the pinhole, only look at the image made on the paper.

17

what is a Lunar eclipse?

A lunar eclipse occurs when the Earth passes directly between the Sun and the Moon, casting a shadow of the Earth on the surface of the Moon. This would happen during a full moon.

18

How can the position of astronomical objects be plotted?

The position of an astronomical object can be plotted with two angles, relative to a point on the Earth.

19

What is the angle of declination? What does a positive angle of declination mean?

The angle of declination refers to whether the object is above or below the line of the equator. A positive angle of declination means that the object will be seen more clearly from a position in the Northern hemisphere.

20

what is the angle of right ascension?

The angle of right ascension refers to the measurement of the angle east from the vernal equinox point (measured in degrees and minutes).

21

what is a solar day ?

A solar day is the time taken for the Sun to move from its highest point in the sky back to its highest point the following day. This is exactly 24 hours.

22

what is a sidereal day ?

A sidereal day is the time it takes for the Earth to actually rotate once on its axis. A sidereal day is four minutes shorter than a solar day.

23

why is the sidereal day shorter than the solar day ?

The sidereal day is shorter than the solar day because as well as rotating on its axis, the Earth also orbits the Sun.

24

why do Solar eclipses not occur every month during the new moon ?

Solar eclipses do not occur every month during the new moon because the Moon does not orbit the Earth in exactly the same plane as the Earth orbits the Sun

25

The path that the Sun traces across the sky is called the what ?

The path that the Sun traces across the sky is called the ecliptic.

26

what is the ecliptic plane?

the plane in which the Earth orbits the Sun is called the ecliptic plane.

27

During most of the new moons in a calendar year, where is the Moon?

During most of the new moons in a calendar year, the Moon is either above or below the ecliptic plane. A solar eclipse can only occur when the Moon passes through the ecliptic plane during a new moon.

28

Can a solar eclipse only occur when the Moon passes through the ecliptic plane during a new moon?

yes

29

How often do solar eclipses occur somewhere on Earth ?

Around 2-5 solar eclipses occur somewhere on Earth every year

30

A total eclipse will occur how often?

total eclipses are rare - . A total eclipse will occur approximately once every 18 months.

31

Because the stars are so far away, their positions in the celestial sphere on a day-to-day timescale can be taken to be what?

Because the stars are so far away, their positions in the celestial sphere on a day-to-day timescale can be taken to be approximately constant, or ‘fixed’.

32

Why do stars appear to move across the sky from east to west ?

Stars appear to move across the sky from east to west because of the rotation of the Earth.

33

what is retrograde motion?

However, the movement of the planets against the background of relatively static stars is more complicated. Sometimes the movement of a planet seems to slow down or go into reverse. This is called retrograde motion.

34

How can retrograde motion be illustrated using Venus, ?

This can be illustrated using Venus, which is closer to the Sun than Earth, so it orbits more quickly. When Venus is on the same side of the Sun as the Earth (position 1), it appears to move in one direction against the stars. However, when Venus is on the other side of the Sun (position 2), it appears to be travelling in the other direction