When will Mars come to Earth? The motion of the planets of the solar system

"When will Mars come to Earth?" - this question at the end of the summer has been worrying many people's minds for more than ten consecutive years. Since August 2003, all those who are not indifferent to the night sky and sensations begin to wait for the appearance of a Red planet about the size of the Moon, or even more. And every year they are visited by disappointment. Mars, however, is not to blame: its actual dimensions exceed the lunar parameters, but fortunately, it simply can not approach us so far as to look like a night star. Let's try to understand why this happens. And to do this, we need to consider the issue from a scientific point of view, to understand where this shocking information came from, and then answer the question: "when will Mars come to Earth?"

Wandering through the sky

Let's start from afar. The motion of the planets of the solar system is subject to certain laws. Movement along orbits and rotation around the axis is accompanied by a slow displacement of the latter and a small "rocking" of the cosmic body. In order to understand this process, one can imagine a yule. For the terrestrial observer, all these phenomena look somewhat different than in the expanses of the cosmos. The planets move across the sky, then ahead of, then catching up with the sun. For a year or several years, their size and brightness can vary.

Forward and Reverse Movement

All planets are divided into external, or upper, and internal, or lower. The first are located behind the Earth's orbit, the latter - closer to our Sun (Mercury and Venus). External planets include Mars, Jupiter, Saturn, Uranus, Neptune. Their movement has for the earthly observer some characteristics. So, it changes at a certain moment from the direct to the back. 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 light is faster than Mars, so sooner or later it catches up with the Red Planet. In astronomy this phenomenon is called "connection with the Sun". The light appears between the planet and the Earth. Now Mars will be visible in the east. For the terrestrial observer, his direct movement will slow down, then the planet will stop and "run" in the opposite direction. There will be a backward movement.

Confrontation

Moving in the opposite direction, the planet describes the arc from east to west. Approximately in 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 resists the luminary. It is important that at such a moment the distance from the Earth to it decreases greatly. With a certain periodicity there are so-called great confrontations. They are characterized by the maximum possible reduction in the distance separating the two cosmic bodies. It was on this day in 2003 that Mars approached the Earth. A photo depicting two moons in the sky also coincided with it, but the reality did not reflect.

How it was

The so-called Martian hoax began in 2003 with electronic mail messages. They said: August 27, the Red Planet will come so close to the Earth that it will look like the second Moon. The corresponding photos flooded the Internet. The day when Mars will approach the Earth at such a record short distance, many were expected with impatience. However, soon after the appearance of the first such messages, the information contained in them was refuted by scientists.

A small mistake

E-mails transmitted, it turned out, either a translation error, or an incorrect understanding of the official announcement of a real astronomical event. On August 27, 2003, the distance between Earth and Mars should have been minimal for the last several thousand years. On the day of the great confrontation, the Red Planet through the telescope with an increase of 75 times could be seen the same as the full moon with the naked eye. The message said that Mars will be larger by 75 times and will look like a night luminary on a full moon.

Scientists, commenting on this information, pay attention to the fact that the diameter of the Red Planet is twice the analogous parameter of the satellite. He overtakes the moon and by weight. At the same time, the distance between Earth and Mars varies from 55 to 400 million km, depending on their relative location. On the one hand, with such a remoteness, the Red Planet can only equal or slightly exceed in brightness Sirius in the sky. On the other hand, if Mars approaches us to such a distance to resemble the Moon, its gravity will cause serious disasters on Earth, that is, hardly any of the people will be able to admire them.

The movement of Mars and the Earth

It should be noted that confrontations between our and the Red Planet occur every two years or so. Earth at this moment is between Mars and the Sun, the distance between two neighbors is reduced. Great confrontations are more rare 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' motion would lie in the same plane, there would always be the same time between oppositions, and the degree of rapprochement would be constant. However, it is not. The trajectory of the Earth's motion is close to a circle, but the orbit of Mars is elongated, and they are located at a slight angle to each other. As a result, during the confrontation, both planets are each time in a new point, and the distance between them varies.

Maximum approach

If Mars and Earth converge at a time when the Red Planet is located near its aphelion, then the distance between them is about 100 million km. This happens usually during the winter in the Northern Hemisphere. If the confrontation occurs at the time of Mars perihelion, the distance is much smaller. Great are those encounters when the planets are separated less than 60 million km. One of them occurred on August 27, 2003. The distance between the planets was then reduced to 55 758 006 km. According to scientists, such rapprochement has not occurred for several thousand years. In 1640, 1766, 1845 and 1924 there were great confrontations, only a little, but still inferior to what happened in 2003.

In the future, the same close passage of two planets is expected in 2287 and 2366. And several more times until the end of the millennium. These days, as on August 27, 2003, Mars will be visible to the naked eye: a small reddish dot in the east after sunset.

Value for science

Since the invention of the telescope, the confrontations of the Earth and Mars have been used to study the Red Planet. It was on such a day in 1877 that astronomer Asaf Hall discovered two satellites, which were later called Phobos and Deimos. Giovanni Schiaparelli during the confrontation considered on Mars the dark spots that marked both the seas and bays. And although it is precisely known that the Red Planet can not boast of water in a liquid state, the terminology of the scientist is still used today.

Now for the study of Mars the confrontations are less valuable, since most of the information comes from interplanetary stations and vehicles that reached the surface of the Red Planet (rover). However, they are important for the implementation of other projects.

Flight to Mars

Today, there are several projects of 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 costs for the flight and its time are reduced.

The great confrontation of 2003 did not remain without the attention of scientists. On this day several interplanetary stations were sent to Mars. In 2018, when two cosmic bodies again strongly approach each other, the United States is planning a test flight of a rocket, which in 2030 will have to deliver astronauts to Mars. Calculating such expeditions is not an easy task. To successfully conduct a 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 in order to study the Red Planet and create conditions on it for the lives of other "Martians". It is his NASA plans to implement in the 30s of this century. Thus, one of the days when Mars will approach the Earth at the minimum distance, can become the date of implementation of one of the most daring fantasies of writers of the last century: the start of colonization by a man of neighboring planets. And our neighbor will be the first cosmic body after the Moon, which people visited.