The difference in the position of the Earth and Sun at the summer and winter solstices is not about their actual physical positions in space, but about the angle of the Earth's tilt relative to the Sun.

Here's the breakdown:

* Earth's Tilt: The Earth is tilted on its axis at approximately 23.5 degrees. This tilt is the primary reason we experience seasons.

* Summer Solstice: During the summer solstice, the Northern Hemisphere is tilted towards the Sun. This means the North Pole is at its maximum tilt towards the Sun, receiving the most direct sunlight. The days are longest in the Northern Hemisphere, and shortest in the Southern Hemisphere.

* Winter Solstice: During the winter solstice, the Northern Hemisphere is tilted away from the Sun. The South Pole is at its maximum tilt towards the Sun, receiving the most direct sunlight. The days are shortest in the Northern Hemisphere and longest in the Southern Hemisphere.

Important Note: The Earth's orbit around the Sun is slightly elliptical, but this doesn't play a significant role in the seasonal changes. The primary factor is the Earth's tilt.

In essence, the Earth and Sun don't change their relative positions drastically between solstices. It's the angle of the Earth's tilt that determines which hemisphere receives the most direct sunlight and experiences summer.