"When will Mars approach the Earth?" - This question at the end of summer has been worrying the minds of many people for more than ten years in a row. Since August 2003, all who are not indifferent to the night sky and sensations begin to wait for the appearance of a Red planet over the head the size of the Moon, or even more. And annually disappointment visits them. Mars, however, is not to blame: its actual size exceeds the lunar parameters, but, fortunately, it simply cannot get close to us to look like a night star. Let's try to figure out why this happens. And for this, you will have to consider the question from a scientific point of view, understand where such shocking information came from, and then answer the question: “when will Mars come to Earth?”
Wandering in the sky
Let's start from afar. The movement of the planets of the solar system is subject to certain laws. The movement in orbits and rotation around the axis is accompanied by a slow displacement of the latter and a small “swing” of the cosmic body. In order to understand this process, one can imagine a hula. For the earth observer, all these phenomena look somewhat different than in the vastness of space. Planets move across the sky, either ahead of or now catching up with the Sun. Over the course of a year or several years, their size and brightness may change.
Forward and reverse movement
All planets are usually divided into external, or upper, and internal, or lower. The former are located beyond the orbit of the Earth, the latter are closer to our Sun closer to our home (Mercury and Venus). Outer planets include Mars, Jupiter, Saturn, Uranus, Neptune. Their movement has some characteristics for the earth observer. So, it changes at a certain moment from direct to backward. When, for example, Mars is visible in the sky in the west some time after sunset, it moves in the same direction as the sun. This is called direct movement. The star has a greater speed than Mars, so sooner or later it catches up with the Red Planet. In astronomy, this phenomenon is called "conjunction with the Sun." The luminary is between the planet and the Earth. Now Mars will be visible in the east. For the earth observer, his direct movement will slow down, then the planet will stop and "run" in the opposite direction. A backward movement will occur.
Confrontation
Moving in the opposite direction, the planet describes an arc from east to west. About the middle of it is an important point. Her name is confrontation. It corresponds to the location of the Earth clearly between the Sun and, for example, all the same Mars. The planet is opposed to the luminary. It is important that at such a moment the distance from the Earth to it greatly decreases. With a certain periodicity, the so-called great confrontations occur. They are characterized by the maximum possible reduction in the distance separating the two cosmic bodies. It was on such a day in 2003 that Mars approached the Earth. Photos depicting two moons in the sky were also timed to it, but they did not display reality.
How it was
The so-called Martian hoax began in 2003 with e-mail messages. They said: On August 27, the Red Planet will come so close to the Earth that it will look like a second moon. Relevant photos have flooded the internet. The day when Mars will approach Earth at such a record short distance was expected by many with impatience. However, soon after the appearance of the first such messages, the information contained in them was refuted by scientists.
Small mistake
Emails transmitted, as it turned out, either a translation error, or a misunderstanding of the official message about a real astronomical event. On August 27, 2003, the distance between Earth and Mars was supposed to be the minimum over the past several thousand years. On the day of the great confrontation, the Red planet through a telescope with a magnification of 75 times could be seen the same as the full Moon with the naked eye. The message said that Mars will become 75 times larger and will look like a night moon on the full moon.
Scientists, commenting on this information, pay attention to the fact that the diameter of the Red Planet is twice as large as the similar parameter of the satellite. He overtakes the moon and the mass. The distance between the Earth and Mars varies from 55 to 400 million km, depending on their relative position. On the one hand, with such a distance, the Red Planet can only equal or slightly exceed the brightness in the sky of Sirius. On the other hand, if Mars approaches us at such a distance to resemble the size of the Moon, its gravity will cause serious disasters on Earth, that is, it is unlikely that any of the people will be able to admire it.
The motion of Mars and the Earth
It should be noted that the confrontation between our and the Red Planet happens every two and a half years. Earth at this moment is between Mars and the Sun, the distance between two neighbors is reduced. Great confrontations are rarer events. Their periodicity is 15-17 years. If the orbit of Mars and the Earth was an exact circle, and the trajectories of the planets would lie in the same plane, then between the oppositions the same time would always pass, and the degree of convergence would be constant. However, it is not. The Earth’s trajectory is close to a circle, but the orbit of Mars is elongated, and they are located at a small angle to each other. As a result, during the confrontation, both planets each time are at a new point, and the distance between them changes.
Maximum proximity
If Mars and Earth converge at the moment when the Red Planet is located not far from its aphelion, then the distance between them is about 100 million km. This usually happens during the winter in the Northern Hemisphere. If the confrontation occurs at the time Mars passes the perihelion, the distance is much less. The rapprochements are called great when planets are separated by less than 60 million km. One of them happened on August 27, 2003. The distance between the planets was then reduced to 55,758,006 km. According to scientists, such a rapprochement has not occurred for several thousand years. In 1640, 1766, 1845 and 1924, great confrontations were observed, only slightly, but still inferior to what happened in 2003.
In the future, an equally close passage of the two planets is expected in 2287 and 2366. and several more times until the end of the millennium. These days, like August 27, 2003, Mars will be visible to the naked eye: a small reddish point in the east after sunset.
Science value
Since the invention of the telescope, the confrontations between Earth and Mars have been used to study the Red Planet. It was on such a day in 1877 that the astronomer Asaph Hall discovered two satellites, which they later called Phobos and Deimos. Giovanni Schiaparelli during the confrontation examined dark spots on Mars, which he designated as seas and bays. And although it is known for certain that the Red Planet cannot boast of water in a liquid state, the terminology of the scientist is still used.
Now, confrontations are less valuable for the study of Mars, since most of the information comes from interplanetary stations and vehicles that have reached the surface of the Red Planet (rovers). However, they are important for the implementation of other projects.
Flight to Mars
Today, there are several projects for manned flights to the Red Planet. Naturally, for such purposes, it is best to use the time of maximum convergence of the two planets. In this case, the cost of the flight and its time are reduced.
The great confrontation of 2003 did not go unnoticed by scientists. On this day, several interplanetary stations were sent to Mars. For 2018, when the two space bodies will again come very close to each other, the United States is planning a test flight of the rocket, which in 2030 will have to deliver astronauts to Mars. The calculation of such expeditions is not an easy task. For a successful flight, it is necessary to take into account a lot of factors, including the time of maximum approach of the planets and the speed of their removal from each other.
One of the projects is the flight of astronauts without their return with the aim of exploring the Red Planet and creating conditions for the life of other "Martians" on it. It is his NASA plans to implement in the 30s of this century. Thus, one of the days when Mars will approach Earth at a minimum distance may be the date of the realization of one of the most daring fantasies of writers of the last century: the start of human colonization of neighboring planets. And our neighbor will be the first space body after the moon that people visited.