Photosynthesis: Chemical process by which plants containing chlorophyll use sunlight to manufacture their own food by converting carbon dioxide and water to carbohydrates, releasing oxygen as a by-product. Respiration: The process in which oxygen is used to break down organic compounds into carbon dioxide and water.
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.
Update Aug. 11: The Perseid meteor shower peaks tonight! Check out the cloud-cover forecast. The pleasantly prolific Perseid meteor shower â a shooting-star show that reigns each August â may become an âoutburstâ this year, if astronomical predictions hold firm. In any given year, when the dark heavens cooperate, the Perseids could peak at 50 to 100 shooting stars an hour. This year, the International Meteor Organization thinks that number may increase to about 150 meteors an hour. Other astronomers are calling for up to 200 meteors an hour.