A meteorite shower is one of the most spectacular but also dangerous phenomena. After all, huge pieces of a meteorites often reach the ground. In March 2015 in India, for instance, the fall of meteorites over the state of Kerala caused a real panic among the inhabitants: they illuminated the night sky, and their flight was accompanied by explosions that shook the entire area. In this case, one of the meteorites fell in the centre of the state.
A meteorite shower is considered to be the fall of interplanetary particles on the Earth’s surface, which were formed after the destruction of a large meteoroid in the upper atmosphere. This process is always accompanied by a glow, sometimes by a low hissing sound. If only one meteorite reaches the Earth’s surface, it will form a crater at the place of the fall. A meteorite shower, in its turn, will create a crater field.
Scientists believe that meteorite shower is quite a frequent phenomenon on our planet: according to their assumptions, about six tons of celestial bodies fall to the Earth during the day, which is about two thousand tons per year.
Not every meteoroid is able to reach the Earth’s surface: it is quite difficult to break through the atmospheric layer of our planet, and most of the interplanetary particles burn up almost immediately. Generally, they are small meteorites (which weight does not exceed several kilograms) that reach the surface.
But giants of incredible size are also not uncommon – the weight of the largest meteorite Hoba found on the Earth exceeds 60 tons. It was found in Namibia and fell to the planet more than 80 thousand years ago (since it is 84% iron, considered to be the largest iron meteorite).
Formation
At great speed, a celestial body enters the Earth’s atmosphere and, as a result of it, becomes heated and begins to glow. If it does not burn up in the upper atmosphere, it will begin to slow down and change the trajectory of its fall. It often happens that the meteorite moves almost horizontally and then abruptly changes direction, begins to fall vertically.
Due to the oncoming air currents, the meteorite is burnt up, and its weight is significantly reduced. A small-sized celestial body will completely burn up without reaching the surface. But if the meteorite is large, it will disintegrate into several separate fragments, which, in turn, form a meteorite shower. The closer the meteorite is to the ground, the more it cools down and the less it glows.
Observing meteorites
Despite the fact that experts monitor meteoroids approaching the Earth with special attention, it is rarely possible to accurately predict exactly when a meteorite shower occurs. The main difficulty lies in the fact that meteoroids constantly fall into the upper layers of the atmosphere, but most of them burn up and do not reach the surface, so people are often wrong-footed.
Astronomers still attempt to learn how to determine when this event will occur. They observe the approaching space objects through orbital stations, create observing stations and organizations on the Earth (both official and amateur) that monitor space.
At the Institute of the Russian Academy of Sciences, for example, there are about 20 astrophysical observatories located far from large cities because the light from them interferes with observing the sky. The main one is located 20 km from St. Petersburg at the Pulkovo Heights.
All received data are sent to the International Meteor Organization, which processes them and makes forecasts for the whole year. Basically, their calendars relate to meteor showers or shooting stars, which differ from the meteorite showers in that they do not reach the Earth and burn up in the atmosphere.
State property
Naturally, any fragment of a meteorite found is a rarity, and there are many who like to get such a stone. It is not all that simple since the found meteorite or its fragments are of great scientific value.
According to international norms, they belong to the country on which they were found, regardless of who found them. To prevent taking out the discovered fragments of the Chelyabinsk meteorite from Russia, the celestial object was included in the items of cultural value.
Perseid meteor shower
This year, the peak of the Perseid meteor shower will fall on August 12-13, when you can see up to two “shooting stars” per minute in the sky.
It is noted that the Moon will pass the new moon phase on August 8 and by the time the shower reaches its peak, it will not interfere with observations.
Planetarium recommends watching the Perseids from midnight to dawn, an enhanced background of meteoric activity starts on August 5 and ends on August 20. The meteors will fly evenly across the sky, so you can look at any part of it.
Bright white meteors will be visible in the sky, sharply tracing the sky. Their speed will reach 60 km per second, and some will glow for up to a couple of seconds.
The Perseids form when the Earth passes through the debris left behind by Comet109/Swift-Tuttle. They burn up in the Earth’s atmosphere and form bright tracks – “shooting stars”.
They get their name from the constellation Perseus because their radiant appears to be located there. In mid-August, the radiant is located on the border of the Perseus, “Giraffe”, and Cassiopeia constellations. They appear from the northeastern horizon after the sunset and rise high by dawn.
The Perseids are rightfully considered to be one of the most spectacular meteor showers of the year.
Most meteor showers are named after the constellations in which their radiant is located. A radiant is a point on the celestial point from which the paths of meteors appear to originate. The Perseid radiant is located in the constellation Perseus, hence the name of the meteor shower.
What is the origin of the Perseids?
The “parent body” of the Perseids is the comet Swift-Tuttle. It moves in outer space and leaves behind a trail of dust particles. When our planet passes through this stream, comet particles enter the Earth’s atmosphere and burn up, creating bright flashes in the sky – meteors.
The comet Swift-Tuttle orbits the Sun once in 133 years. It was last observed from the Earth in 1992, and the next time it will return only in 2126. Despite such a rare occurrence, the comet Swift-Tuttle leaves behind enough cosmic dust for us to enjoy the Perseids every year.