Astronomy Picture of the Day—20180817

Discoverthe cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2018 August 17

Parkervs Perseid

ImageCredit & Copyright: Derek Demeter (Emil Buehler Planetarium)

Explanation:The brief flash of a bright Perseid meteor streaks across the upper right inthis composited series of exposures made early Sunday morning near the peak ofthe annual Perseid meteor shower. Set up about two miles from Space LaunchComplex 37 at Cape Canaveral Air Force Station, the photographer also capturedthe four minute long trail of a Delta IV Heavy rocket carrying the Parker SolarProbe into the dark morning sky. Perseid meteors aren't slow. The grains ofdust from periodic comet Swift-Tuttle vaporize as they plow through Earth'supper atmosphere at about 60 kilometers per second (133,000 mph). On its way toseven gravity-assist flybys of Venus over its seven year mission, the ParkerSolar Probe's closest approach to the Sun will steadily decrease, finallyreaching a distance of 6.1 million kilometers (3.8 million miles). That's about1/8 the distance between Mercury and the Sun, and within the solar corona, theSun's tenuous outer atmosphere. By then it will be traveling roughly 190 kilometersper second (430,000 mph) with respect to the Sun, a record for fastestspacecraft from planet Earth.