Perihelion
Perihelion is the moment a planet or object reaches its closest point to the Sun in its orbit. It's the orbital minimum distance, opposite aphelion.
Perihelion is the point in an orbit where a celestial body is closest to the Sun. It marks the minimum distance in an elliptical path around a central star and is the opposite of aphelion, the farthest point. This term applies to planets, comets, and asteroids orbiting the Sun.
What this means in real life
A comet approaching the inner solar system travels fastest and shines brightest when it reaches perihelion—its closest pass to the Sun—before slowing and dimming as it recedes back into deep space.
What it isn’t
It is not the same as the closest approach to Earth. An object can be at perihelion (nearest the Sun) while still being far from our planet, since Earth itself orbits the Sun.
Commonly misused online
Social media often claims Earth's perihelion causes summer heat, when in fact Earth is at perihelion during Northern Hemisphere winter. Seasons are driven by axial tilt, not orbital distance.