1.1 Planet Earth Flashcards
What is the Earths atmosphere mainly made up of?
Nitrogen (78%), Oxygen (21%), Argon (1%) and Carbon Dioxide (0.04%)
What percentage of Earth is covered by liquid water?
70%
What’s the diameter of Earth?
12,756 km/ 13,000 km
How many km is the Earth flattened by?
42 km
What degree is the polar axis tilted to?
66.5°
When are the spring an autumnal equinoxes?
March 21st (Spring) September 22nd/23rd (Autumnal)
What degrees North and South are the Tropics of Cancer and Capricorn?
- 5°N (Cancer)
23. 5°S (Capricorn)
What’s the meridian?
An imaginary circle passing through the poles at any given point on the Earth’s surface
What’s a zenith
A point in the sky that is directly above the observer
What are the benefits of our atmosphere?
- It absorbs harmful solar UV radiation.
- It absorbs harmful X-rays and gamma-rays from space.
- It regulates the temperature so we rarely experience ‘extremes.’
- It provides us with oxygen to breathe.
- It partly protects us from meteoroids.
What are the advantages of having telescopes high up in the sky?
- No atmosphere to blur images.
- No light pollution.
- No adverse weather problems.
- Longer observing periods.
What are some of the drawbacks of our atmosphere?
- Light refracts which makes stars “twinkle” which distorts resolution.
- The selective scattering of the shorter (bluer) wavelengths of sunlight by gas molecules in the atmosphere make the sky appear blue preventing astronomers from observing during the day.
- The absorption and reflection of the majority of electromagnetic radiation from space.
Name two gases in the Earths atmosphere absorbs large amounts of infrared radiation?
Carbon dioxide and water vapour.
What shape is the Earth?
Oblate spheroid.
What is a solstice?
When the sun resides directly over the Tropic of Cancer (21st June) or the Tropic of Capricorn (21st December).
