What are perihelion and aphelion?
The perihelion is the point in the orbit of the Earth, or any planet, comet, asteroid, or orbiting object, where it is closest to the sun
The aphelion is the opposite, the point in the orbit when the object is farthest from the sun
Most orbiting bodies have elliptical orbits, not circular orbits, therefore the bodies are not a fixed distance from the sun at all times.
Here, (1) is the aphelion, (2) is the perihelion, and (3) is the sun (not to scale).
The distance of the Earth to the Sun is:
147.1 million km (91.4 million miles) at perihelion in early January
152.1 million km (94.5 million miles) at aphelion in early July
Both words come from Greek, where 'peri' means 'near', and 'Helios' is the Greek god of the sun, and 'apo' means 'away'.