Gaze at the stars tonight, and you'll find some wobbling. Stars with planets around them exhibit "radial velocity" as planets pull on their host stars, like a tug-of-war. These tiny wobbles help astronomers discover numerous planets. Even Earth wobbles our sun, as we search for celestial neighbors in the vastness of space. Astronomers measure movements that are almost imperceptible, seeking new worlds beyond our solar system. The cosmic dance of wobbling stars unfolds! 🌌✨
Look up at the stars tonight. Stare. Do you see them wobbling? No?
Stars with planets around them wobble in a movement astronomers can measure as “radial velocity.”
Why the wobble?
Well, stars have MUCH higher masses than their orbiting planets. Stars dominate those relationships.
Mass equals gravitational influence.
But planets do have a type of pipsqueak power. Planets pull a wee bit on the star they are orbiting. It’s like an uneven game of tug-of-war.
And so, planets pull stars towards and away from our sensors rhythmically. Tiny amounts. The rate detected is that ‘radial velocity’.
And that’s how we have discovered so many planets. The wobble!
Earth wobbles our sun up to 10 centimeters per second—the speed of a tortoise walking. Maybe aliens are detecting that wobble right now!
In looking for planets around other stars astronomers on Earth and maybe elsewhere are measuring movements that are hardly there at all.