Experienced astronomers are well aware that the orbital speed of the planets is directly related to their distance from the center of the system - the Sun. Well, for people who are just starting to study the amazing science of celestial bodies, it would certainly be interesting to learn more about this.
What is orbital velocity?
Orbit is the trajectory along which a particular planet moves around the Sun. It is not at all a perfect circle, as some people who do not understand astronomy think. Moreover, it doesn’t even look like an oval, because there are a large number of factors, with the exception of the Sun’s gravity, that can affect the movement of celestial bodies.
It is also worth immediately dispelling another well-known myth - the Sun is not always exactly in the center of the orbit of the planets revolving around it.
Finally, it should be noted that not all planetary orbits lie in the same plane. Some are significantly out of it - for example, if you depict the standard orbits of the Earth andVenus on an astronomical map, you can make sure that they have only a few intersection points.
Now that we have more or less de alt with the orbits, we can return to the definition of the term of the orbital velocity of the planets. This is how astronomers call the speed with which the planet moves along its trajectory. It may vary slightly - depending on which celestial bodies pass nearby. This is especially noticeable on the example of Mars: every time it passes in relative proximity to Jupiter, it slows down a little, being attracted by the gravitational field of this giant.
Scientists have long established the dependence of the speed of the planets around the Sun on the distance to it.
That is, the closest planet to the Sun - Mercury - moves the fastest, while Pluto's speed is the smallest in the solar system.
What's up with this?
The fact is that the speed of each planet corresponds to the force with which the Sun attracts it at a certain distance. If the speed is less, then the planet will gradually approach the star and burn out as a result. If the speed is too high, then the planet will simply fly away from the center of our solar system.
Every astronomer, even a beginner, knows perfectly well that the force of gravity decreases with distance from the Sun. That's why, to keep its place in the solar system, Mercury has to rush around at breakneck speed, Mars can move more slowly, and Pluto barely moves at all.
Mercury
The closest planet to the Sun is Mercury. This is where we will start studying the speed of the planets of the solar system.
It boasts not only the smallest orbital radius, but also small size. It is the smallest complete planet in our system. The distance from Mercury to the Sun is less than 58 million kilometers, due to which the temperature at its equator on a hot day can reach 400 degrees Celsius and even more.
In addition to staying in its orbit with such a close proximity to the Sun, the planet has to move at a tremendous speed - about 47 kilometers per second. Since the length of the orbit is quite small due to the small radius, it completes a complete revolution around the star in just 88 days. That is, the New Year can be celebrated there much more often than on Earth. But the speed of rotation of the planet around its own axis is very small - Mercury makes a complete revolution in almost 59 Earth days. So, a day here is not much shorter than a year.
Venus
The next planet in our system is Venus. The only one where the sun rises in the west and sets in the east. The distance to the center of the system is 108 million kilometers. Due to this, the speed of the planet in orbit is much less than that of Mercury (only 35 kilometers per second). Moreover, this is the only planet whose orbit is really an almost perfect circle - the error (or, as experts say, eccentricity) is extremely small.
True, the length of the orbit (according tocompared to Mercury) it has much more, which is why Venus makes a full path in only 225 days. By the way, another interesting fact that distinguishes Venus from all other planets of the solar system: the period of rotation around the axis (one day) here is 243 Earth days. Therefore, the year here lasts less than a day.
Earth
Now you can consider the planet that has become a home for mankind - the Earth. The average distance to the Sun is almost 150 million kilometers. It is this distance that is usually called one astronomical unit - they are used when calculating small (by the standards of the Universe) distances in space.
It's hard to believe, but while you are reading this article, you are moving along with the Earth at a speed of almost 30 kilometers per second. But even with such an impressive speed, in order to make a complete revolution around the Sun, the planet spends more than 365 days or 1 year on it. But it rotates around its axis quite quickly - in just 24 hours. However, these and many other facts about the Earth are obvious to everyone, so we will not consider our home planet in detail. Let's move on to the next one.
Mars
This planet is named after the fearsome god of war. In all respects, Mars is as close as possible to Earth. For example, the speed of the planet in orbit is 24 kilometers per second. The distance to the Sun is about 228 million kilometers, which is why the surface is rather cool most of the time - only during the day it warms up to -5 degrees Celsius, and at night it gets cold to -87 degrees.
But the day here is almost equal to the Earth - 24 hours and 40 minutes. To simplify, even a new term was coined to denote the Martian day - sol.
Since the distance to the Sun is quite large, and the trajectory of movement is much longer than that of the Earth, the year here lasts quite a long time - as many as 687 days.
The planet's eccentricity is not too large - about 0.09, so the orbit can be considered conditionally round with the Sun located almost in the center of the circumscribed circle.
Jupiter
Jupiter got its name in honor of the most powerful ancient Roman god. Not surprisingly, it is this planet that boasts the largest size in the solar system - its radius is almost 70 thousand square kilometers (the Earth, for example, has only 6,371 kilometers).
The distance from the Sun allows Jupiter to rotate quite slowly - only 13 kilometers per second. Because of this, it takes the planet almost 12 Earth years to make a full circle!
But the day here is the shortest in our system - 9 hours and 50 minutes. The tilt of the axis of rotation here is extremely small - only 3 degrees. For comparison, our planet has a temperature of 23 degrees. Because of this, there are no seasons on Jupiter at all. The temperature is always the same, changing only during short days.
Jupiter's eccentricity is quite small - less than 0.05. Therefore, it evenly winds circles strictly around the Sun.
Saturn
This planet is not too inferior to Jupiter in size, being the second largestcosmic body in our solar system. Its radius is 58 thousand kilometers.
The speed of the planet in orbit, as mentioned above, continues to fall. For Saturn, this figure is only 9.7 kilometers per second. And to pass with such a low speed one has a really long distance - the distance to the Sun is almost 9.6 astronomical units. In total, this path takes 29.5 years. But the day is one of the shortest in the system - only 10.5 hours.
The planet's eccentricity is almost the same as that of Jupiter - 0.056. Therefore, the circle turns out to be quite even - the perihelion and aphelion differ by only 162 million kilometers. Considering the huge distance to the Sun, the difference is quite small.
Interestingly, Saturn's rings also revolve around the planet. Moreover, the speed of the outer layers is much less than the inner ones.
Uranus
Another giant of the solar system. Only Jupiter and Saturn surpass it in size. True, Neptune also bypasses it in weight, but this is due to the high density of the core. The average distance to the Sun is really huge - as many as 19 astronomical units. He moves rather slowly - he can afford it at such a great distance. The speed of the planet in orbit does not exceed 7 kilometers per second. Because of such slowness, it takes Uranus as much as 84 Earth years to travel a huge distance around the Sun! A very decent time.
But around its axis it rotates amazingly fast - a full turncompleted in just 18 hours!
An amazing feature of the planet is that it rotates around itself not vertically, but horizontally. In other words, all the other planets in the solar system make a revolution "standing" at the pole, and Uranus simply "rolls" in its orbit, as if lying on its side. Scientists explain this by the fact that during the formation of the planet collided with some large cosmic body, because of which it simply fell on its side. Therefore, although in the conventional sense the day here is very short, at the poles the day lasts 42 years, and then the night lasts the same number of years.
Neptune
The ancient Roman ruler of the seas and oceans gave his proud name to Neptune. No wonder even his trident became a symbol of the planet. In terms of size, Neptune is the fourth planet in the solar system, only slightly inferior to Uranus - its average radius is 24,600 km versus 25,400.
From the Sun, it keeps at a distance of an average of 4.5 billion kilometers or 30 astronomical units. Therefore, the path that he makes, passing the orbit, is really huge. And if you consider that the circular speed of the planet is only 5.4 kilometers per second, then there is nothing surprising in the fact that one year here equates to 165 Earth years.
Interesting fact: there is a fairly dense atmosphere here (although it consists mainly of methane), and sometimes there are winds of amazing strength. Their speed can reach 2100 kilometers per hour - on Earth, even a single impulse of such power would instantly destroy any city, leaving no stone unturned there.
Pluto
Finally, the last planet on our list. More precisely, not even a planet, but a planetoid - it was recently deleted from the list of planets due to its small size. The average radius is only 1187 kilometers - even for our Moon this figure is 1737 kilometers. Nevertheless, its name is rather formidable - it was assigned in honor of the god of the underworld of the dead among the ancient Romans.
On average, the distance from Pluto to the Sun is about 32 astronomical units. This allows him to feel safe and move at a speed of only 4.7 kilometers per second - Pluto still will not fall on a hot star. But to make a complete revolution around the Sun with such a huge radius, this tiny planet spends 248 Earth years.
It also rotates very slowly around its axis - it takes 152 Earth hours or more than 6 days.
Besides, the eccentricity is the largest in the solar system - 0.25. Therefore, the Sun is far from the center of the orbit, but shifted by almost a quarter.
Conclusion
This is the end of the article. Now you know about the speed of the planets in our solar system, and also learned many other factors. Surely now you understand astronomy much better than before.
