How to loop through array and find if key

So basiclly I want o loop through an error (what i already did) and print the other key

var planet = "sun";
    var planets = [{
            type: "sun",
            desc: "sun"
            }, {
            type: "moon",
            desc: "moon"}];

        var pln = planets.length; 
        for (var i = 0; i < pln; i++) {
            console.log(planets[i]);
        }

How can i I find out if the var planet is in the array planets and print out the description from that key if so?