Every year at the turn of July and August, shooting stars fly out of the constellation Perseus. The meteor swarm, which is why it was named Perseida, will be better observed this year than in previous years. Exceptionally, the Moon will not disturb it with its radiation. If the night sky is not obscured by clouds, the brightest will be the Perseids on the night of August 12-13.
These days, the Moon is “backing up”, its crescent is waning, and on August 8 it will be new, so it will not be visible in the sky at all. The sky is black, and just then the shooting stars are best seen. This lunar phase comes this year when the orbital swarm Perseid crosses the orbit of the planet Earth. Their particles burn in the Earth’s atmosphere, and humans observe a phenomenon called shooting stars. On the night of August 12-13, the Perseids will be at their peak this year.
“The frequency of meteors gradually rises until the night of the maximum. During this night, we will see up to 80 meteors per hour in the moonless sky outside the city, especially between midnight and four o’clock in the morning,” astronomer Petr Horálek described. According to him, up to twenty of them can be really clear.
But the night of the swarm maximum will be rich not only in meteors. In the early evening of August 12, it will be possible to observe the “evening”, ie the planet Venus, above the western horizon. Later, a bright section of the Milky Way, part of our galaxy, will appear. It stretches across the entire sky and Saturn shines to the left of its center. East of it, Jupiter will be even brighter. Shortly before midnight, the constellation Taurus begins to appear above the northeast. Early in the morning, the outgoing Orion will end the spectacle.
“Conditions are ideal this year mainly because the Moon in the sky will only be in the phase of a narrow crescent. At night, the maximum sets in the evening and will not be disturbed by its light. It will be possible to see even the faintest meteors,” the astronomer warned.
Exploration of asteroids outside Earth’s orbit
Within ten years, the Czech company SAB Aerospace, focused on the space industry, is going to send a mission to the asteroid out of Earth’s orbit. The satellite should fly around it and determine the composition of its surface. It uses a laser to evaporate a piece of the asteroid, and the camera then determines its composition in the same way as the composition of a meteor plasma.
“In the future, we can also imagine a fleet of small satellites examining interplanetary dust released from asteroids using mass analyzers, as demonstrated by the Slavia project,” explains Martin Ferus of SAB Aerospace.
The Slavia project (Space Laboratory for Advanced Variable Instruments and Applications) was created at the request of the European Space Agency and the Czech Ministry of Transport, which allocated more than a billion crowns for the mission and related projects. Within four years, the Czechs will send two satellites into Earth orbit. These are to study the composition of small bodies that move in the solar system, meteoroids and asteroids, or asteroids. They should provide information on which of the many cosmic bodies the extraction of raw materials would be important.
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To people watching the night sky, shooting stars seem to fly out of the constellation Perseus. They enter the Earth’s atmosphere at a speed of 59 kilometers per second. They begin to glow at an altitude of 120 kilometers above the ground, fading tens of kilometers below. They come into the atmosphere from one direction. Therefore, it seems as if their trajectory originates from a single point in the sky. This is professionally called a radiant.
From our point of view, the constellation Perseus does not fit at all, so meteors are visible all night. Most of them can be seen from midnight to dawn. At that time, Perseus is high above the horizon and rises to the headboard. Therefore, most meteors glow just above the horizon.
Although the Perseids have been active since July 17, they disappear from the sky on August 24, but astronomer Horálek warns that their maximum frequency decreases significantly after the night.
People have been observing them for millennia, the first surviving mentions of them come from the 3rd century. People noticed them then shortly after the martyrdom of St. Lawrence, a popular saint in the then Roman Empire. As a church dignitary, he refused to obey Emperor Valerian’s order to hand over church property to the ruler, preferring to distribute it to the poor. He was executed on August 10, 258, a few days later people saw glittering tears falling from the night sky. Roji Perseid therefore became known as the “tears of St. Lawrence”.
As an astronomical phenomenon, the Perseids were studied by the Italian astronomer Giovanni Schiaparelli in the second half of the 19th century. “He was the first to find a direct connection between meteors and comets and determined that Perseid originated in dust from the periodic comet 109P Swift-Tuttle,” Horalek said. The dust particles of a meteor swarm are smaller than grains of sand and form a brittle cometary material, evaporating as they pass through the Earth’s atmosphere. The comet last approached the Sun in 1992, and will not do so again until 2126.
Also this year, on the night of the maximum, an annotated observation of Perseid takes place in the area of the observatory in Ondřejov, Central Bohemia. The Astronomical Institute of the Academy of Sciences of the Czech Republic organizes it on the local radar meadow. According to the organizers, people should come before dark on August 12, so that they do not disturb other participants with light later. Observations of the sky will also be in the Štefánik Observatory on Petřín in Prague. Just after the maximum, on Saturday 14 August, the traditional Day and Night event takes place in Jizerka.
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