Test your knowledge of Near Earth Objects and the hazards posed by their collision with the Earth.

Q1. What is meant by AU?
Astronomical Unit
Asteroid Unit
Antipole Unit
Astrological Unit
Astronaut Uniform

Q2. What is an asteroid?
A type of star
A small moon
A rocky or metallic minor planet
A fragment of a broken up planet
A rock from beyond our Solar System

Q3. Where is the main asteroid belt?
Between the planets Jupiter and Neptune.
Around the Moon.
Close to Venus
Beyond the planet Pluto.
Between Mars and Jupiter.

Q4. How often do NEOs collide with Earth?
Every day.
Every year.
Every 100 years.
Every million years.
Every 100 million years.

Q5. How far is 1 AU?
One light second.
One light year.
The distance between the Earth and the Moon.
The distance between the Earth and the Sun.
5000 km.

Q6. Why can Radar not be used to track most asteroids?
Radar needs air and doesn't work in space
Radar is too expensive
Radar has a limited range
There are too few Radar transmitters
Radio waves are absorbed by asteroids

Q7. How wide is the largest known crater on Earth?
50 km
100 km
150 km
300 km
600 km

Q8. How long ago did meteor crater in Arizona form?
1000 years ago
10,000 years ago
50,000 years ago
100,000 years ago
1 million years ago

Q9. What creatures are thought to have been made extinct by the K/T impact?
Dinosaurs
90% of all Palaeozoic species
Mammals
45% of all Mesozoic species
Ammonites

Q10. What is the largest known crater on the Moon?
Mare Orientale
Copernicus
Mare Imbrium
Tycho
Mare Marginis

Q11. Astronomers are trying to find all NEOs over what size?
10 m
100 m
1 km
10 km
100 km

Q12. When were most large craters on the Moon formed?
In the last million years
More than 4.0 billion years ago
In the last billion years
Between 100 and 18 million years ago
Between 4.0 and 3.8 billion years ago

Q13. Which NEO was visited by the NASA NEAR spacecraft?
2002 MN7
Eros
Toutatis
Ceres
Vesta

Q14. Why do comets have tails?
Because their ice turns to gas
Because they drag gas in from the outer Solar System
Because they strongly reflect sunlight
Because they move so quickly
Because they are made of gas

Q15. Approximately how many meteorites fall every year?
30
300
3000
30,000
300,000

Q16. Why do asteroids wander out of the asteroid belt?
Because of collisions with comets
Because of Jupiter's and Saturn's gravity
Because of collisions with other asteroids
Because of Mars' gravity
Because of solar flares

Q17. How many Near Earth Asteroids are there bigger than 1 km?
About 10
About 100
About 1000
About 10,000
About 100,000

Q18. What are tektites?
Small meteorites
Glassy objects formed as molten spray from impacts
Cosmic dust particles found on the Earth
Comets without tails
A type of asteroid

Q19. What is the probability of dying in an impact?
1 in 250
1 in 2,500
1 in 25,000
1 in 250,000
1 in 2,500,000

Q20. What is the Torino Scale?
A scale used by scientists to estimate impact hazards
A scale used to communicate impact hazards
A scale used to measure the size of asteroids
A scale that describes how often impacts occur
A scale used to measure the size of an impact crater