During the night of August 11th, a meteor shower called ’Perseids’ might put up a memorable show. After the moon sets, which occurs around 1:00 AM local time, it might be possible to see up to 200 ’shooting stars’ per hour. Below, what you need to know about this astronomical event.
Despite their name, shooting stars are actually small rocks (meteoroids) falling towards the Earth due to our planet’s gravitational attraction. As they move rapidly through the atmosphere, they reach very high temperatures due to friction with air particles. This makes them burn and become visible to the human eye. The trail they leave is called ’Meteor’. Due to their tiny size, they usually almost completely burn in a fraction of a second. In some very exceptional cases, large meteors can continue the hot descent and hit the ground. If they also survive the crash, they get promoted immediately to the ’meteorites’ class. Generally speaking a meteoroid producing a meteor needs to be at least as large as a marble to reach the Earth and eventually become a meteorite. Some Burning facts:
Average meteorite velocity: 30000 miles/hour (48000 km/h)
Max temperature: 3000 F (1650 C)
The Meteor Crater in Arizona was formed 50000 years ago by an object 160 feet (50 meters) across
… yes, impacts like the one that produced the Meteor Crater are extremely rare
Meteor showers occur when the Earth’s orbit intercepts the dusty trail of periodic comets. Comets are dirty ice-balls coming from the cold periphery of the Solar system, captured in eccentric orbits around the Sun. When getting closer to our star, they melt slowly, releasing gas and dust which make the comet visible (those beautiful comet tails). The dusty leftover of the comet pave the comet’s orbit. When the Earth comes close to one of these dusty cometary highways, the particles can be captured by the planet’s gravity and fall towards the surface. This creates the meteor shower, which repeats every time the crossing occurs, that is once per year.