Premature ventricular contractions (PVCs, PVC) are premature heartbeats originating from the ventricles of the heart. Premature ventricular contractions are premature because they occur before the regular heartbeat. The heart has four chambers. The upper two chambers are the atria, and the lower two chambers are the ventricles.
When Can I See the Perseids? The Perseid meteor shower, one of the brighter meteor showers of the year, occurs every year between July 17 and August 24. The shower tends to peak around August 9-13. The best time to view the Perseids, and most other meteor showers, is when the sky is the darkest.
The Sky This Week for July 15 to July 24 2016. Saturn shines, Mercury and Venus have a close encounter, and the Delta Aquariads meteor shower flies by. For observers in North America, the Moon appears 3Â° above Saturn this evening while the ruddy 1st-magnitude star Antares in Scorpius the Scorpion lies 10Â° below the Moon.