Whenever the subject of mosquito control comes up, someone gives a fervent argument for installing purple martin houses and bat houses. Stores that cater to bird enthusiasts often tout the purple martin houses as the best solution for keeping your yard mosquito free.
A short period comet is conventionally defined as a comet having an orbital period of less than 200 years. What is the maximum possible aphelion distance for a short period comet with a perihelion of 0.5 AU? Where does this place the comet relative to the outer planets? (3)
Semi-synchronous and similar orbits. When the orbital period is half as long as the rotational period, the orbit is usually described as semi-synchronous. It is possible to calculate the semi-major axis of a semi-synchronous orbit using Kepler's third law of planetary motion. With the knowledge about the semi-major axis of a synchronous orbit and the ratio between the two orbits: The fraction f is the quotient of the period of the synchronous orbit (a 1) and second orbit (a 1/f). When the second orbit is a semi-synchronous orbit this quotient is 2: An orbit where the orbital period is lower than the rotational period has some advantages, as some bodies don't allow synchronous orbits but opportunities for semi-synchronous orbits.