topic one

• What is the Goldilocks zone?


  The Goldilocks zone is the habitable zone where conditions are just right for liquid water to exist.
• What is Earth's average distance from the Sun in Astronomical Units (AU)?

  Earth's average distance from the Sun is about 1 AU.
• What is the approximate distance of 1 AU in kilometers?

  1 AU is approximately 149.6 million kilometers.
• What is the tilt of Earth's rotation axis?

  Earth's rotation axis is tilted at an angle of about 23.5°.
• What is the difference between equatorial and polar radii of Earth?

  The difference is about 21 km, with the equatorial radius being larger.
• What is Earth's shape?

  Earth's shape is an oblate spheroid.
• What causes Earth's seasons?

  Earth's seasons are caused by its axial tilt and its revolution around the Sun.
• What is the average time it takes for Earth to complete one rotation?

  One complete rotation takes approximately 24 hours.
• What is the Coriolis effect?

  The Coriolis effect is the deflection of moving objects due to Earth's rotation.
• What is the average distance of Earth's orbit from the Sun?

  The average distance is about 1 AU or 149.6 million km.
• What is the shape of Earth's orbit around the Sun?

  Earth's orbit is elliptical, not perfectly circular.
• How long does it take for Earth to complete one orbit around the Sun?

  One complete orbit takes approximately 365.25 days.
• What are the key points about Earth's position in the Solar System?

  - Earth is the third planet from the Sun. - It is located in the Goldilocks zone. - Earth is one of eight planets orbiting the Sun. - It is classified as a terrestrial planet. - It is part of the inner planets along with Mercury, Venus, and Mars.
• What are the effects of Earth's rotation?


  - Causes the cycle of day and night - Influences wind patterns through the Coriolis effect - Affects ocean currents - Establishes time zones
• What are the key points about Earth's orbit around the Sun?

  - Earth's orbit is elliptical. - Average distance from the Sun is about 1 AU (149.6 million km). - One complete orbit takes approximately 365.25 days.
• What primarily causes the seasons on Earth?

  Earth's axial tilt and its revolution around the Sun
• How does Earth's axial tilt affect the seasons?

  It causes different parts of Earth to receive varying amounts of sunlight throughout the year
• What defines the ecliptic plane?

  Earth's orbit around the Sun
• What is the significance of the equinoxes?


  Day and night are nearly equal in length
• What is seasonal lag?

  The phenomenon where the warmest and coldest times of the year occur after the solstices
• What are the main characteristics of Earth's seasons?

  - Caused by Earth's axial tilt of about 23.5°. - Opposite seasons in Northern and Southern Hemispheres. - Summer solstice: longest day; Winter solstice: shortest day. - Equinoxes: day and night are nearly equal. - Angle of sunlight affects temperature and energy distribution. - Seasonal lag occurs after solstices.
• What is the mean diameter of the Earth according to the Pearson Edexcel Astronomy syllabus?

  13,000 km
• Why is Earth's mean diameter considered a fundamental value in astronomy?


  It serves as a reference point for comparing sizes in our solar system and beyond.
• What is the actual mean diameter of the Earth?

  About 12,742 km
• How does Earth's mean diameter help in visualizing cosmic scale?

  It provides a standard unit for many astronomical comparisons.
• What are the key points regarding Earth's mean diameter in astronomy?

  - Rounded value of 13,000 km - Standard unit for astronomical comparisons - Aids in visualizing and understanding cosmic scale
• Why might astronomers use Earth's diameter as a reference point when discussing other celestial bodies?

  It provides a familiar scale for comparison.
• How do you convert Earth's diameter to its radius?

  Radius = Diameter ÷ 2
• What is Earth's radius if its diameter is 13,000 km?

  6,500 km
• How do you calculate Earth's circumference using its diameter?

  Circumference = π × Diameter
• What is Earth's circumference if its diameter is 13,000 km?

  Approximately 40,840 km
• How can other celestial bodies' sizes be expressed in relation to Earth's diameter?

  By expressing them as multiples of Earth's diameter.
• What is the formula to calculate Earth's volume using its diameter?

  Volume = (4/3) × π × (Diameter/2)³
• What is Earth's volume if its diameter is 13,000 km?


  Approximately $(4/3) \times \pi \times (6,500 \text{ km})^3$
• What are some examples of celestial bodies compared to Earth's diameter?

  - Moon: ≈ 0.27 × Earth's diameter ≈ 3,510 km - Mars: ≈ 0.53 × Earth's diameter ≈ 6,890 km - Sun: ≈ 109 × Earth's diameter ≈ 1,417,000 km
• How does Earth's diameter relate to the Sun's diameter?

  The Sun's diameter is approximately 109 times Earth's diameter.
• How does surface area relate to diameter when comparing celestial bodies?

  Surface area scales with the square of the diameter.
• If Saturn's diameter is approximately 9.5 times Earth's diameter, how many times larger is Saturn's surface area compared to Earth's?

  About 90 times larger.
• If Jupiter's diameter is about 11 times that of Earth, how many times larger is Jupiter's surface area compared to Earth's?

  About 121 times larger.
• How is Earth's diameter relevant to orbital characteristics?

  - Influences gravitational field - Affects orbital velocities of satellites - Used in calculating escape velocity