Planetary Fact Files

Mercury	Venus	Earth	Mars	Jupiter	Saturn	Uranus	Neptune

Earth

The planet we live on. It is the third planet from the sun, has an atmosphere and temperature suitable for life.

Earth is the largest terrestrial planet in our solar system.

It was formed approximately 4.54 billion years ago.

Planet Earth is travelling around the sun at 67,000 miles per hour, meaning it takes 365.256 days to complete an orbit (hence the leap year every four years to make up for the 0.256 days each orbit).

71% of Earth's surface is covered in water.

The atmosphere is about 78% nitrogen and 21% oxygen.

Missions

There have been over 75 successful missions to our Moon (this includes landings, orbitals, fly-bys and gravity assists).

The first man-made satellite was successfully put into orbit in 1957 by the Russian space program, it was called Sputnik. We now have over 2200 man-made satellites in orbit around our planet, this number is increasing rapidly.

Earth also has two space stations in orbit, the ISS and Tiangong 2. The very first space station was the Salyut 1 which was successfully launched in 1971.

The farthest working man-made object from Earth is the Voyager 1 probe, which at the time of writing this was 12.8 billion miles away (it was the first probe to successfully leave our solar system). You can visit NASA's Voyager probe live data webpage to find out how far away it is right now.

Questions

Use the information above to answer these questions:

1. Even with us having a leap year every four years we are still lose 0.006 days per orbit. How long will it take before a double leap year would be required?
2. What do you think is third most common gas in the Earth's atmosphere?
3. Why is the atmosphere on Earth easier to move through than that on Venus?
4. Give three reasons why having an increasing number of satellites in orbit around Earth is a bad thing.

Answers

To check your answers please see the answer sheet. This should only be used after attempting all questions.