Stars don't actually wobble in the way we think of a physical object wobbling. The "wobble" we observe is actually a shift in the star's light that we detect on Earth. This shift is caused by the gravitational pull of planets orbiting the star.

Here's how it works:

1. Gravity's Influence: Planets orbiting a star exert a gravitational pull on the star, causing it to move slightly back and forth.

2. Doppler Effect: This movement creates a Doppler shift in the star's light. Think of it like the sound of an ambulance siren: as it approaches, the sound waves are compressed, making the siren sound higher-pitched; as it moves away, the sound waves are stretched, making the siren sound lower-pitched.

3. Spectral Analysis: We can detect this Doppler shift in the star's light by analyzing its spectrum. When the star is moving towards us, its light shifts slightly towards the blue end of the spectrum (blueshift); when it's moving away, its light shifts towards the red end (redshift).

4. Orbital Period: The pattern of these shifts reveals the orbital period of the planet. The longer the period of the wobble, the longer the planet's orbit around the star.

Important Note: This "wobble" is extremely subtle. It's not something you can see with the naked eye. Astronomers use sensitive instruments to measure the Doppler shifts in the star's light and deduce the presence and properties of orbiting planets.

In summary, the "wobble" of a star is not a physical wobble, but a subtle change in its light due to the gravitational pull of orbiting planets. By analyzing the shifts in the star's light, astronomers can discover and study planets around other stars.