Final answer:
Different constellations are visible at different times of the year because Earth's orbit changes our perspective of the night sky, leading to the Sun being projected against different stars along the ecliptic. As a result, constellations like Orion are visible in winter when they are opposite the Sun at night.
Step-by-step explanation:
We see different constellations at different times of the year, such as Orion in winter, because Earth's position in its orbit changes throughout the year. As Earth revolves around the Sun, we see the Sun projected against different parts of the sky ecliptic, which is the apparent path the Sun follows over the course of a year. The ecliptic passes through a set of constellations traditionally known as the zodiac. At different times of the year, different constellations lie along this path and are visible at night, while others are obscured by the Sun's brilliance during the day.
During one complete orbit around the Sun, it appears to us that the Sun has made a full circuit of the sky along the ecliptic. This means that over the course of a year, we gradually see different constellations in the night sky at different times. For example, we see Orion during the winter months because this is when that part of the sky is opposite the Sun at night. Moreover, the stars and constellations appear fixed relative to each other, creating a consistent backdrop that appears to rotate as Earth turns. This celestial sphere concept helps astronomers track the movements and positions of celestial bodies.