Astronomy

Question 1

What is the equation of weight?

Answer 1

weight (Newtons) = mass (kg) x gravitational field strength

Question 2

Where is out solar system?

Answer 2

In the milky way

Question 3

What is a galaxy?

Answer 3

A large collection of billions of stars

Question 4

What is the universe?

Answer 4

A large collection of billions of galaxies

Question 5

What is the gravitational field strength on other planets?

Answer 5

Earth - 10N/Kg
Moon - 1.6N/Kg
Mars - 4N/Kg
-g is different on other planets and the moon from that on Earth

Question 6

What are moons?

Answer 6

Non luminous objects, we see them because they reflect light from the sun

Question 7

Does the Earth have a moon?

Answer 7

It has one that orbits the earth in 29.5 days (1 lunar month)
Mars - 2 moons
Jupiter - over 60 moons
Uranus - 27 moons

Question 8

What are planets?

Answer 8

Non luminous objects, we see them because they reflect light from the sun
The orbits of planets are elliptical with the sun close to the centre.
They are held in orbit by the gravitational pull of the sun. (GF also cause moons (earth), comets (sun) and artificial satellites (earth) to orbit their things) Gravity decreases quickly as you get further away

Question 9

What are comets?

Answer 9

• Comets orbit the sun, with a very elliptical orbit.
• They are made of dust and ice (‘icy mud balls’)
• Comets speed up nearer the sun as the gravitational forces increase nearer the sun
• Comets move slower further away from the sun as the gravitational forces are smaller.
• Close to the sun some of the comets frozen gases evaporate forming a long tail that shines in the sunlight
• The tail always points away from the sun

Question 10

What is an asteroid?

Answer 10

Are minor planets or rocks that orbit the sun

Asteroid belt between the orbits of Mars and Jupiter

Question 11

What is a satellite?

Answer 11

Satellites are objects that orbit a planet
Moons are natural satellites
Manufactured objects are artificial satellites

Question 12

What is the equation for orbital speed?

Answer 12

(2x🍰x orbital radius) / time period

Question 13

How do you calculate the speed of a satellite?

Answer 13

speed = distance / time

distance travelled = 2 x pie x radius of orbit

Question 14

What does gravitational force do?

Answer 14

1. Causes moons to orbit planets
2. Causes the planets to orbit the sun
3. Causes artificial satellites to orbit the Earth
4. Causes comets to orbit the sun

Question 15

Where do you draw the weight arrow on a diagram from?

Answer 15

The weight of a body acts through its centre of gravity (draw from centre of body)

Question 16

What is the orbits of comets like?

Answer 16

Elliptical

Question 17

What is the orbits of moons and planets like?

Answer 17

• Usually slightly elliptical
  1. With very large masses like stars and planets, gravity is very big and acts a long way out
  2. The closer you get to a star or planet, the stronger the force of attraction
  3. Because of this stronger force, planets nearer the Sun move faster and cover their orbit quicker
  4. Moons and artificial satellites are also held in orbit by gravity
  5. The further out from Earth they orbit, the slower they move