Mercury is the closest planet to the Sun.
This planet got its name in honor of the god Mercury - the messenger of the gods, the patron of trade and travelers - because of its high speed of rotation around the Sun.
Mercury moves faster than all the planets - 174,000 km/h.
It makes a complete revolution around the Sun in 88 (87.97) Earth days in an elongated orbit, sometimes moving away from the Sun by 70 million km, while the shortest distance to the Sun is 46 million km.
Planets located further from the Sun have longer orbits. It takes the Earth about 365 days - one year - to travel across the Sun. The planets are similar to each other in another important way. It takes the earth 24 hours or one day to rotate once. When the Earth rotates, the parts that face the Sun light up - this is daytime. The parts that look away from the Sun are dark - this is night.
How was he found?
If you could visit other planets, you might find strange and amazing worlds. Some are dry and rocky, while others are balls of swirling gases with hard centers. Some planets are much hotter than Earth, so hot that nothing can live there. This is because they are so close to the Sun. Other planets are far from the Sun. They are very, very cold, colder than any place on Earth.
And the duration of a sidereal day on Mercury (one revolution around its axis) is 58.65 Earth days.
Quickly rushing along its orbit, Mercury lazily turns around its axis. In one Mercury year, the planet manages to rotate around its axis by one and a half revolutions.
The average time interval between the two upper culminations of the Sun on this planet is 176 days. Interestingly, when it is near perihelion (closest distance from the Sun), the Sun for an observer on the surface of the planet can move in the opposite direction for 8 days.
The Earth is at the right distance from the Sun - it is not too hot and not too cold. The Earth has water to drink and air to breathe. Earth is the only planet in our solar system where plants, animals and people can live.
If you could visit any other planet in the solar system, which planet would you visit and why? Write a few sentences about why you visited this planet.
- Which planet occupies the most a short time for the orbit of the Sun?
- Which planet takes the longest time to orbit the Sun?
- Which planet has its back on its side?
- What planet has a moon with volcanoes that spews ice?
Distance from Mercury to Earth varies from 82 to 217 million km.
The planet is visible to the naked eye.
Over the course of several days, when observed from Earth, Mercury changes its position relative to the Sun from the west (morning visibility) to the east (evening visibility).
Mercury's rotation axis and its orbit are practically perpendicular.
Mercury is so small that its mass (3.3·1023 kg) is 1/20 the mass of the Earth.
The radius of Mercury is only 2439.7 ± 1.0 km, which is less than the radius of Jupiter's moon Ganymede and Saturn's moon Titan.
The proximity to the Sun and the rather slow rotation of the planet, as well as the extremely thin atmosphere, lead to the fact that Mercury experiences the most dramatic temperature changes in the Solar System.
The temperature on the sunny side of the planet is 420 °C.
Temperature at dark side drops to -190 °C.
The average density of Mercury is 5.43 g/cm³ (slightly less than the density of the Earth). This density indicates an increased content of metals in its depths.
The planet has an almost spherical shape. The acceleration of gravity on its surface is g = 3.72 m/s2.
But a recent study suggests that Mercury may share a rare trait with our much more hospitable planet Earth: tectonic activity. If this is true, Mercury may be the only other planet in the solar system to experience earthquakes. Or, in the case of the smaller planet, "mercury".
Does Mercury have an atmosphere?
The discovery is forcing scientists to reevaluate what they know about planetary geology. Geologically active planets and moons have a warm inner core that creates a current that moves and crackles on the solid surface. A planet like Mercury was considered too small to retain enough heat for geological activity.
Mercury, along with Venus, Earth and Mars, belongs to the terrestrial planets.
When the Mariner 10 spacecraft transmitted the first close-up images of Mercury, astronomers threw up their hands: there was a second Moon in front of them! The surface of Mercury was dotted with a network of craters different sizes, just like the surface of the Moon. Their size distribution was also similar to that of the Moon. Most of the craters were formed as a result of falling meteorites.
Mercury is very similar to the Moon.
It turned out that on Mercury, like on the Moon, there are two main types of terrain - analogues of lunar continents and seas. Continental areas are the most ancient geological formations of Mercury, consisting of areas dotted with craters, mountainous and hilly formations, and intercrater plains. Analogues of the lunar seas are considered to be the smooth plains of Mercury, which are younger in age than the continents, somewhat darker than the continental formations, but still not as dark as the lunar seas and there are significantly fewer of them than on the Moon. Such areas on Mercury are concentrated in the area of the Zhary Plain (diameter 1300 km).
It turns out, however, that the interior appears to be warm enough and that there is enough liquid metal at its core or around its core to generate a magnetic field, making the alien planet more Earth-like than most solar system bodies. Similar geological activity is shared only by the moon and perhaps Europa or Titan. While it is possible that Venus is another geologically active planet, the thick clouds around the planet have made precise exploration of it geological processes, which is still impossible.
Pictures and Map of Mercury
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Which planet has the longest day?
The angles on Mercury also indicate that Mercury actually shrinks as it cools. While our moon has been shrinking for the same reason, Mercury's contraction has been more extreme over the last few billion years. "Mercury has the potential for many more earthquakes than the moon because it has shrunk much more than the moon," Watters said.
This can be very good if you like cosmic sky shows, because from time to time the familiar night skies can change dramatically. Monday will be one of those times when it makes an unusually close pass of the Earth, coming closer and looming larger than at any time since.
It is almost no secret that many celestial bodies revolve around the Sun, which, in addition to planets, also include their satellites, comets, asteroids and other particles. Modern scientists have managed not only to observe them through telescopes and other devices, but even to conduct research on their samples obtained through the use of probes. All this now allows us to confidently answer many questions about planets close to the Sun, their satellites and other celestial bodies.
This is what lies behind the cosmic comfort. The orbit that a planet takes around its parent star is fixed and knowable. It takes the earth 256 days to make one circle around the sun. For Mars, a year is 93 days. It's good for Neptune; one Neptunian year takes 79 Earth years.
These different orbital speeds mean that the distance between any two planets is always changing. For example, when Earth loops into band 3 of the solar system, it sometimes ends up on the complete opposite side of the sun from Mars, putting the two planets 249 million miles apart. However, once every two years, Earth circles Mars, overtaking its poker sister and bringing the two planets closer to about 9 million miles.
General description of the planets of the solar system
There are a total of nine planets in our solar system. Each of them is distinguished by its astronomical and structural characteristics. Similar to the Earth, they all rotate not only around their own axis, but also around a common celestial body. The planets closest to the Sun are Mercury, Venus, Earth and Mars. They are also commonly called “terrestrial planets.” Their common characteristics are their relatively small size, the predominance of solid elements in their structure, the absence of rings, and a small number of satellites. After them come the planets of the Jupiter group, which include Jupiter itself, as well as Saturn, Uranus and Neptune. They are quite characteristic dense atmosphere, as well as light components surrounding the nuclei. Around each of them there are rings consisting of fragmented substances, and numerous satellites rotate. As for Pluto, it is constantly in the dark, and some scientists do not consider it a planet at all.
However, not all close encounters between Earth and Mars are created equal. Few planets in any solar system orbit the Sun in a perfect circle. Instead, they follow a slightly egg-shaped path, meaning each orbit has a perihelion and an aphelion. For Earth, perihelion is 4 million miles and apelius is 5 million miles.
Planets are usually not perfectly aligned in a plane, circling neatly around the star's equator. Most of them are slightly inclined relative to this midline, moving above the equatorial plane of its sun on one part of its orbit, and below on the other. Mars' orbit is tilted 65 degrees relative to the Sun's equator; The ground is a little more heady 155 degrees.
Mercury
Almost every schoolchild knows which planet is the closest to the Sun. This is Mercury. In terms of size, it is in eighth place among all representatives of the system. Interesting fact is that Jupiter (Titan and Ganymede, respectively) are larger in size. is 4880 kilometers, and its orbit passes at a distance of almost 58 million kilometers from the Sun. In its entire history, only one ship has flown to this planet (Mariner 10 in 1974-1975), so now there is information about only 45 percent of its surface. According to scientists' research, temperature fluctuations here range from 90 to 700 o K. 
For two planets to make a particularly close approach, like Mars and Earth are about to do, this means that the inner planet must be in its apel phase when it passes Mars; and that Mars must be in perihelion phase. This also means that the planets must be close to each other in tilt toward the sun, both above and below the solar equator.
What are Saturn's rings made of?
It's all lining up now that Mars and Earth are set to pass each other within a relatively screaming 8 million miles on Monday, and even casual cloud watchers will notice the difference without the aid of a telescope. Mars is approaching the low point in its perihelion cycle now, but it's not quite there yet, and the Earth will be swept by when it reaches that nadir.
The closest planet to the Sun is somewhat reminiscent of the Moon. The fact is that it is missing and on the surface is a large number of craters and huge chasms. In terms of density, Mercury is in second place in the system after Earth. This planet's magnetic field is weak. Its power compared to the Earth is one hundred times less. Mercury has no satellites, and can be seen even with the naked eye.
Pictures and Map of Mercury
And this is very close, thank you very much. About 5 billion years ago, the primordial Earth suffered a near-death experience when a rogue planetary size of Mars collided with it, sending out a cloud of debris believed to be raw materials for the Moon. The actual Mars is not going to jump onto its orbital lane and move forward.
But in a solar system born of violence, it is always nice if very close encounters never become too close. Although each planet is very different from each other, they all share a number of characteristics. The main similarities are that they all have solid surfaces that are fairly similar in size, especially compared to the Outer Planets, have a small number of moons, and take a relatively short amount of time to complete an orbit around the Sun. In cosmic terms they are also very close to each other.
Venus
The second planet, judging by the distance from the Sun, is Venus. In the case when a criterion such as magnitude is taken as a basis, it is in sixth place. Its diameter is more than 12 thousand kilometers, and its orbit passes 108 million kilometers from the Sun. The first to approach Venus was Mariner 2 in 1962.
The diagram below shows the orbits of the four Inner Planets. It shows how close they are to each other compared to Jupiter, the first of the Outer Planets. Despite their similarities, each planet has its own characteristics, although none other than Earth are known to support life. Below is short description every planet. To view a planet in more detail, select the planet name.
There were no fireworks, no ball falling from the spire, no lifeless celebrities celebrating. But it happened just as it did last year, and the year before that, and all the years stretching back to the dawn of our planet 5 billion years ago. The Earth revolves around the Sun in an ellipse, not a circle. Until this time, for thousands of years ago, everyone thought that the planets revolved around the sun in perfectly steep paths.
Compared to Earth, Venus rotates very slowly. Due to the synchronization of its orbit and rotation period, only one side of this planet is always turned towards us. Very often, Venus is called “sister of the Earth,” which is due to their great similarity. Indeed, its diameter is 95% of our planet, and its mass is 80%. The density and chemical composition. At the same time, one cannot help but note the fact that in many other parameters there are radical differences. There is every reason to believe that Venus once had a large amount of water, which boiled away over time, so it is now completely dry. The planet has no magnetic field (due to its slow rotation) and no satellites. You can see it with the naked eye, because in our sky it is the brightest “star”.
But we make an elliptical orbit, which means that we are sometimes closer to the Sun, and sometimes further away. This change is only about 3%, which would probably look very similar to a perfect circle. On the right is an ellipse. Some people think that the distance to the Sun is the reason we have seasons. But as you can see, this difference is so small that it hardly has any impact. There are some, but they are small. We are slightly cooler on average when we are further away than our distance from the Sun.
This is the opposite of what would be expected if distance to the Sun alone caused the seasons. Calculating the exact time of perihelion turns out to be a little tricky; it is different every year. However, when reflected, it makes sense. Picture this: Imagine two children holding hands and spinning around. One child is bigger than the other, so the smaller child does big circle, and the larger child makes a small circle as they swing, with both of them spinning around their center of mass.
Earth
The third from the Sun is the Earth. Its diameter is 12,756.3 km, and its orbit passes at a distance of 149.6 million km from the celestial body. Like other planets close to the Sun, it has a history of approximately 5.5 billion years. In the system, the Earth is considered the densest celestial body. Water covers 71% of its area. Interesting feature is that only here it exists in liquid form on the surface. Scientists suggest that the stability of temperature on our planet is largely due to this. The only natural one is the Moon. In addition to it, many artificial bodies were launched into orbit. 
The Moon and Earth are locked under gravity, but the principle is the same. Because the Earth makes this smaller circle once a month, the shape of its path around the Sun is a bit wonky. This can change the time of perihelion by several hours! Not only that, but the distance is calculated between the centers of the Earth and the Sun; this is because the equations used include gravity, and this is done under the assumption that the objects are actually point sources, literally infinitesimal points that have mass and gravity.
Considering the vast distance between the Earth and the Sun compared to their size, this math works out pretty accurately. Well, if you measured the size of the Sun very carefully, it would appear a little larger today than on any other day of the year. The difference is quite small, as this picture from astrophotographer Anthony Ayiomatitis shows.
Mars
In fourth place in terms of distance from the Sun and in seventh position in magnitude is Mars. Its orbit is located at a distance of almost 228 million km from the celestial body, and its diameter is 6794 km. The first ship that flew to it was Mariner 4 in 1965. Like other planets close to the Sun, Mars boasts a rather original and interesting terrain. There are many craters, mountain ranges, planes and hills here. The average is about minus 55 degrees. It is possible to see it even with the naked eye. As for satellites, this planet has two of them: which rotate near its surface.
This is the Sun at aphelion and perihelion, and obviously it's not a huge deal. But this also means that every day from here until we reach aphelion, we will be a little further from the Sun, heading up our orbit. Many people like to make New Year's resolutions to improve their lives, starting at the beginning of the year. If you have done this, the aphelion is a good reference point to check. At times, the Earth will move 468 million km around the Sun and be 5 million km further away. What will you be doing at the same time?
Unlike fruits, vegetables or peppers, the eight planets are so different in their orbits around the Sun. For example, while Venus experiences hellish conditions due to heat, poisonous gases and acid rain, ice storms dominate its appearance on Neptune. Additionally, Neptune, the planet's terminal planet, suffers the most from storms and icy winds.