Chapter 12: Beyond Earth (Earth and Space)

(i) – (d) Moon (ii) – (c) Mars (iii) – (a) Orion (iv) – (b) Venus

(i) – (d), (ii) – (c), (iii) – (a), (iv) – (b)

(i) The letters are M, A, R, S: the planet is MARS.

(ii) Two riddles:

• My first letter is in VAN but not in PAN; my second is in BED and also in RED; my third is in NET but not in SET; my fourth is in BUS but not in BAS; my fifth is in SUN but not in BUN. I am the brightest planet. (VENUS)
• My first letter is in EGG but not in IGG; my second is in CAT and also in ANT; my third is in RUN but not in BUN; my fourth is in TOP but not in POP; my fifth is in HOT but not in POT. I am the planet we live on. (EARTH)

(i) MARS (ii) e.g. riddles for VENUS and EARTH.

(i) Sirius. It is a star far away from our Solar System. Comets, asteroids and Pluto (a dwarf planet) all go around the Sun.

(i) Sirius

(ii) Pluto. It is now called a dwarf planet.

(ii) Pluto

Sirius is brighter. It is the brightest star in the night sky; the Pole Star is not very bright, but it is important because it stays in nearly the same place, above the north.

Sirius

No. In the figure the large planet with the broad rings (Saturn) is shown after the planet with thin rings (Uranus); Saturn should come before Uranus. The correct order of the planets from the Sun is:

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

(The asteroid belt lies between Mars and Jupiter.)

Not correct: Saturn and Uranus are swapped. Correct order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

• Big Dipper: look for seven bright stars, four making a cup (a quadrilateral) and three making a curved handle. Join them.
• Little Dipper: a smaller, fainter group of seven stars of the same shape, with its handle pointing the other way.
• Pole Star: draw a line through the two stars at the outer edge of the Big Dipper's cup (the "pointer stars") and extend it about five times the gap between them; it reaches a moderately bright star: this is the Pole Star. It is the last star of the handle of the Little Dipper.

Join the seven stars of the Big Dipper (cup and handle) and the smaller Little Dipper; the Pole Star is found by extending the line of the two pointer stars of the Big Dipper's cup, and it is at the end of the Little Dipper's handle.

• Orion looks like a hunter: find three bright stars close together in a short straight line; this is Orion's belt. Above it are two bright stars (the shoulders) and below it two bright stars (the knees or feet). Join these seven stars to make Orion.
• Sirius: follow the line of Orion's belt downwards to the left (south-east); it points to a very bright star: Sirius, the brightest star in the night sky.

Join the three stars in a row (Orion's belt) with the two stars above and two below to form Orion; extend the belt line downwards to reach the very bright star Sirius.

The stars are present in the sky during the day too, but the Sun is so bright that its light, spread through our atmosphere, makes the whole sky bright. The faint light of the far-away stars cannot be seen against this bright sky. At dawn the sky becomes brighter and the stars fade away; at dusk, as the Sun sets and the sky darkens, the stars become visible again.

The Sun's bright light lights up the whole sky, so the much fainter starlight cannot be seen during the day; stars become visible when the sky darkens at dusk.

Yes, the Big Dipper appears to move: it slowly goes around the Pole Star (in an anticlockwise direction when we face north), while the Pole Star stays almost in the same place. For example, the Big Dipper may be to the right of the Pole Star at 8 pm, above it at about 2 am, and so on. In your sketch, draw the Pole Star at the centre and the Big Dipper at different positions around it, labelled with the times (e.g. 8 pm, 10 pm, 12 am).

This happens because the Earth rotates on its axis, and the Pole Star lies almost exactly above the Earth's axis (over the North Pole), so the other stars seem to circle around it.

Yes: it seems to move in a circle around the Pole Star (anticlockwise, facing north), while the Pole Star stays fixed, because the Earth rotates.

The Night Sky (a short poem)

When the Sun goes down and the birds fly home,
The sky turns dark like a velvet dome.
The Moon peeps out with a silver smile,
And stars come twinkling, mile after mile.

The Big Dipper scoops the milky light,
The Pole Star guides the sailors right,
Orion hunts with his shining belt,
And Sirius glitters, the brightest yet.

I lie on the roof and count each star,
And wonder how many, and oh, how far!
Then sleep comes softly, the sky stays bright,
The stars keep watch all through the night.

For example, a poem about the Moon, the Big Dipper, the Pole Star, Orion and Sirius shining in the night sky.