Threats to Earth Flashcards
What are asteroids?
- Asteroids are mini-planets or planetoids orbiting the Sun.
- Most orbit between Mars and Jupiter.
- They are large rocks that were left after the formation of the solar system.
What is an asteroids relative mass when compared to jupiter?
Asteroids have relatively low masses compared to the mass of jupiter.
What does the mass of an object determine?
Its gravitational force.
How were the bodies in space formed?
All bodies in space, including planets, were formed when clouds of gas and dust collapse together due to gravitational forces of attraction.
What prevents asteroids becoming planets?
Jupiter’s gravitational force prevents asteroids from joining together to form another planet.
What do scientists think the origin of the moon is?
Scientists believe our moon was a result of the collision between two planets in the same orbit. The iron core of the other planet melted and joined with the Earth’s core, less dense rocks began to orbit and they joined together to form our moon.
What is the scientific evidence for the origin of the moon?
- The average density of Earth is 5500 kg/m3 while that of the moon is only 3300 kg/m3.
- There is no iron on the moon.
- The moon has exactly the same oxygen composition as the Earth, but rocks on Mars and meteorites from other parts of the Solar System have different oxygen compositions.
What evidence do geologists have for asteroid collisions on Earth.
- Near to a crater thought to have resulted from an asteroids impact, they found quantities of the metal iridium. A metal not normally found in the Earth’s crust but common in meteorites.
- Many fossils are found below the layer of iridium, but few fossils are found above it.
- Tsunamis have disturbed the fossil layers, carrying some fossil fragment up to 300 km inland.
What orbits do comets pass through?
Most comets pass inside the orbit of mercy and well beyond the orbit of pluto.
What type of orbit does a comet have?
An elliptical orbit.
What happens to a comet when it gets close to a Sun?
- As the comet passes close to the Sun, the ice melt and solar winds blow the dust into the comet’s tail which always points away from the sun.
- The speed of a comet increases as it approaches the Sun and decreases as it gets further away. This is because of the changing gravitational attraction.
Scientists are constantly …
Monitoring and plotting the paths of comets and other near planet objects (NEOs).
What would happen if an NEO collided into the Earth?
If an NEO is on a collision course with Earth, it would be the end of life on Earth. To avoid this, one option would be to explode a rocket near to the NEO which could alter its course enough to miss Earth.
