2Y: Sun, Earth & Moon Flashcards
How long does it take the Earth to rotate around the Sun?
How long does it take the Earth to rotate on it’s axis?
How long does it take the Moon to rotate around the Earth?
365.25 Days
24 Hours
28 Days
Review Diagram of Earth Rotation around the Sun
What causes the Earths seasons? (Hint: axis tilt)
The planet’s axis of rotation is tilted at an angle of 23.5 degrees relative to our orbital plane – the plane of Earth’s orbit around the sun.
As a result, different parts of the planet receive different amounts of light energy during the year. This causes the seasons.
What happens in the Northern Hemisphere during the summer? (2)
- Norther Hemisphere is tilted towards the sun, so longer days.
- More energy is falling on Norther Hemisphere, as the sun rays are reflected over a smaller area, so hotter days.
What happens in the Northern Hemisphere during the winter? (2)
- Norther Hemisphere is tilted away the sun, so shorter days
- Less energy is falling on Norther Hemisphere as the sun rays are reflected over a larger area, so colder days.
When the NH is titled away, what tilt is the SH?
When the NH is titled away from the sun, the SH is tilted towards the Sun.
Thats why when it’s winter in NH, it’s the summer in the SH.
Does the moon create it’s own light?
No - the moon does not create its own light. We see the moon because it reflects light from the sun.
Why do the different phases of the moon cause high and low tides?
This is because of the gravitational force between the moon and the earth.
Why does the visibility of the moon change during the 28 days?
The parts of the moon which is visible to us change during the month because the moon is in orbit around the earth (28 days).
What are the main 4 phases of the Moon?
- Day 1 NEW MOON From the earth we cannot see the moon because the sunlit part of the moon is afcing away from us.
- Day 7 FIRST QUARTER We see half of the lit part of the moon.
- Day 14 FULL MOON We all of the lit part of the moon.
- Day 21 THIRD QUARTER We see half of the lit part of the moon.
- Day 28 NEW MOON We have a new moon and the whole cycle begins again.
What is a Lunar Eclipse?
The Lunar Eclipse happens when the sun, the earth and the moon line up with each other, in such a way that the earth lies between the sun and the moon.
Because the earth is blobking the light from the sun, it casts a shadow on the moon.
Can only happen during a full moon.
What is a Solar Eclipse?
A solar eclipse happens when the Sun, the Moon and the Earth line up and the moon lies between the Earth and the Sun.
Because the moon is blocking some of the sunlight, it casts a shadow on the earth.
- Partial Darkness/Shadow = Penumbra
- Dull Darkness/Shadow = Umbra
Wear eye protection hen viewing a solar eclipse.
Who was Edwin Hubble?
Edwin Powell Hubble was an American astronomer.
He only became an atronomer after WW1.
He used the best telescopes of the time to observe other galaxies.
What did Edwin Hubble observe?
He measured the speed that the galaxies were travelling through space at and found that further away galaxies were travelling faster.
This meant the universe was expanding.
https://www.youtube.com/watch?v=LE_wbOw39Mk
If astronomers all agree that the universe is expanding, did all of the universe originally expand from one place?
What is this theory called?
The BIG BANG theory.
What is the ‘Big Bang Theory’?
The Big Bang Theory says that at one point in time, everything existed at one single point (called a singularity). Approximately 13.8 billion years ago, this singularity started to expand very, very quickly.
What is the timeline of the Big Bang Theory? (4 Stages)
- First seconds after big bang, birth of subatomic particles.
- ~ 380,000 years later, electrons and nuclei combined into atoms.
- ~ 300,000,000(300 million) years later, beginning formation of the stars and galaxies.
- ~ 9 billion years later the formation of the solar system and earth.
What is the evidence for the Big Bang Theory?
- Universe is expanding: Hubbles observation that universe is expanding and therefore orignated in one place(singularity).
- Cosmic Microwave Background Radiation: This radiation can be detected throughout the universe (with very sensitive radio telescopes). It is radiation that could come from a Big Bang.
What is the Hubble Space Telescope?
This telescope was launched in orbit around the earth in 1990 and is still working. Because it is outside the atmosphere, it can take much clearer pictures of deep space.
