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Earth Orbit Plot

Earth is closest to the Sun in early January (perihelion) — so seasons are not caused by distance. Tilt is the reason.

Perihelion ~4 Jan · Aphelion ~4 Jul

Distance 0.9833 AU on day 4

Before you start

Earth is closest to the Sun in early January. Northern-hemisphere winter is therefore not ‘because we are far’.

Key idea

Seasons come from tilt. Distance varies by only about 3%.

What you see

  • Earth on a slightly eccentric ellipse
  • Day-of-year slider
  • Perihelion / aphelion labels

Try this

  1. Day 4 vs day 185
  2. Read the AU distance

Why it matters in Hong Kong

Hong Kong’s summer is in July near aphelion — slightly farther from the Sun, still hotter because of tilt.

Common mistakes

  • Using distance as the seasons explanation

Glossary

Aphelion
Farthest point from the Sun, early July for Earth.

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