The period of rotation of Venus around the sun. Gravitational waves spun Venus. Size, mass and orbit of the planet Venus

News from our hot neighbor. Researchers report that the speed of Venus's rotation around its axis varies depending on the time of day. This happens due to the mutual influence of the thick atmosphere of Venus with its fast currents with the mountains on the surface of the planet. These conclusions are based on a study of a phenomenon that astronomers reported last year: temporary wave patterns can be traced in the atmosphere of Venus. The newest results confirm the assumption that in this case we are talking about an atmospheric wave that is caused by a rock formation.

"Naked" Venus. This image shows a surface that is always and reliably hidden from view by dense clouds. Photo by NASA/Jet Propulsion Laboratory-Caltech

She is never shown naked: the view of the surface of Venus is always hidden by a thick veil of clouds of sulfuric acid. The energy of the sun's rays accelerates this layer to high speeds. And it orbits the entire planet in just four days. And this despite the fact that Venus itself rotates around its axis very slowly: for one such complete revolution it needs 243 Earth days. True, there are surprisingly significant ambiguities regarding the speed of its rotation around its own axis. Different measurements showed slightly different results. And now a group of researchers led by Thomas Navarro from the University of California at Los Angeles has found an explanation for such discrepancies.

Shock waves appear in the atmosphere of Venus

The explanation is based on a study of a remarkable structure in the "coat" of Venus, which astronomers discovered last year in images from the Japanese space agency JAXA's Akatsuki probe. A temporary structure appears in the upper atmosphere of Venus, stretching approximately 10 thousand kilometers from north to south. Scientists see the reason for it in the interaction of the atmosphere with the surface of the planet.

The most unusual thing was that the structure does not spread further under the influence of winds, but appears only over a certain area of ​​the surface. Analysis and assessments of the known structures of Venus show that the center of this arc-shaped formation is constantly hovering above the rock formation. Therefore, astrophysicists hypothesized that this unstable formation is an atmospheric wave, created when gas masses rise above mountainous topography.

Atmospheric waves effect

To test this hypothesis and show possible interaction effects, Navarro and his colleagues simulated possible circulations in the Venusian atmosphere. And the result showed that the arc-shaped structure can indeed be explained by atmospheric waves. As models have shown, they are formed at the appropriate intensity of solar radiation over mountain formations - they appear in the light of the “afternoon” Sun and disappear again at dusk.

In addition, as part of the modeling, scientists found that these waves can cause significant fluctuations in atmospheric pressure. And it is they, as models show, that are able to change the speed of rotation of Venus around its axis, depending on the time of day.

According to the researchers, the effect, although relatively small, is clearly visible. This means that interactions between the rocky planet and its atmosphere could, at least partially, explain the discrepancy between measurements of how fast Venus rotates on its axis, Navarro and his team say.

1. Venus is the second planet from the Sun, closest to Earth. The minimum distance from Earth is 42 million km.
2. The equatorial diameter of Venus is 12,100 km (95% of Earth’s)
3. Mass 4.87∙10 24 kg (0.82 earth), density 5250 kg/m3
4. The rotation of Venus around its axis is reverse, this means that sunrise on the planet occurs in the west, sunset in the east. Venus rotates very slowly around its axis, one revolution is 243.02 Earth days.
5. The period of revolution around the Sun is 224.7 Earth days; average orbital speed - 35 km/s.
6. Venus is one of the most beautiful luminaries in the sky. Over the course of 585 days, periods of its evening and morning visibility alternate. When observed from Earth, Venus changes shape and size. Venus appears at its largest in its crescent phase.
7. Venus is a hot, waterless planet with a colossal atmospheric pressure of 9.2 MPa.
8. The planet's atmosphere consists mainly of carbon dioxide, which traps the planet's heat. Over millions of years of the greenhouse effect, temperatures reached 480°C, and would have been even higher if clouds had not reflected 80% of the sun's heat. The atmosphere of Venus extends to an altitude of 250 km. The clouds of Venus are formed by drops of sulfuric acid, and sulfur ended up in the atmosphere of Venus as a result of fashionable and prolonged volcanic activity.
9. Science does not yet know why the atmosphere of Venus is involved in one giant hurricane. Near the surface of Venus the wind is weak, no more than 1 m/s; near the equator at an altitude of over 50 km it intensifies to 150-300 m/s. The nature of the electrical activity in the atmosphere of Venus, where lightning flashes twice as often as on Earth, is also not clear.
10. A complete mapping of Venus has been completed spacecraft Magellan in 1990-1992 using radar methods.

>> Rotation axis of Venus

Rotation of Venus around its axis: description of the axis of an inverted planet with a photo, retrograde Venus, comparison with the Earth, seasons, counterclockwise rotation.

You will be surprised, but the tilt of Venus’s axis reaches 177.3°. Yes, it seems too strange, so let's figure it out. The Earth's index is 23.5°. This leads to the formation of the seasons, so we expect Venus' rotation axis to create some real madness there.

Oh no. Let's brush up on your geometry knowledge a little. A full circle is 360° and half a circle is 180°. So if we subtract 177.3° from 180°, we get 2.7°. In fact, this is how Venus is tilted relative to the solar system's ecliptic plane because it is perfectly inverted.

Venus is unique because it is the only one among solar planets rotates in the opposite direction (Venus retrograde). If you observe from above, then everyone rotates counterclockwise, and Venus follows it.

Perhaps everything on the planet turned upside down due to a strong blow in the past. Or Venus has slowed down due to tidal locking with our star.

We know that the axis is responsible on Earth for the change of seasons. Winter comes to the northern hemisphere when the north pole is tilted away from sunlight. In summer the situation changes. Devoid of seasonality, Venus is forced to exist with a constant temperature heating of 462°C.

The second planet from the Sun, Venus, is the closest to Earth and, perhaps, the most beautiful of the planets terrestrial group. For thousands of years she has attracted curious glances from scientists of ancient and modern times to mere mortal poets. No wonder she has the name greek goddess love. But its study rather adds questions than gives any answers.

One of the first observers, Galileo Galilei, observed Venus with a telescope. With the advent of more powerful optical devices such as telescopes in 1610, people began to observe the phases of Venus, which closely resembled the phases of the moon. Venus is one of the brightest stars in our sky, so at dusk and in the morning, you can see the planet with the naked eye. Watching its passage in front of the Sun, Mikhailo Lomonosov in 1761 examined a thin rainbow rim surrounding the planet. This is how the atmosphere was discovered. It turned out to be very powerful: the pressure near the surface reached 90 atmospheres!
The greenhouse effect explains the high temperatures of the lower layers of the atmosphere. It is also present on other planets, for example on Mars, due to it, the temperature can rise by 9°, on Earth - up to 35°, and on Venus - it reaches its maximum, among planets - up to 480° C.

Internal structure of Venus

The structure of Venus, our neighbor, is similar to other planets. It includes the crust, mantle and core. The radius of the liquid core containing a lot of iron is approximately 3200 km. The structure of the mantle - molten matter - is 2800 km, and the thickness of the crust is 20 km. It is surprising that with such a core, the magnetic field is practically absent. This is most likely due to the slow rotation. The atmosphere of Venus reaches 5500 km, the upper layers of which consist almost entirely of hydrogen. Soviet automatic interplanetary stations (AMS) “Venera-15” and “Venera-16” were discovered on Venus back in 1983 Mountain peaks with lava flows. Now the number of volcanic objects reaches 1600 pieces. Volcanic eruptions indicate activity in the planet's interior, which is locked under thick layers of basalt shell.

Rotation around its own axis

Most of the planets in the solar system rotate around their axis from west to east. Venus, like Uranus, is an exception to this rule, and rotates in the opposite direction, from east to west. This non-standard rotation is called retrograde. Thus, a full revolution around its axis lasts 243 days.

Scientists believe that after the formation of Venus, there was a large amount of water on its surface. But, with the advent of the greenhouse effect, the evaporation of the seas began and the release of carbon dioxide anhydrite, which is part of various rocks, into the atmosphere. This led to an increase in water evaporation and an overall increase in temperature. After some time, the water disappeared from the surface of Venus and entered the atmosphere.

Now, the surface of Venus looks like a rocky desert, with occasional mountains and undulating plains. From the oceans, only huge depressions remained on the planet. Radar data taken from interplanetary stations recorded traces of recent volcanic activity.
In addition to the Soviet spacecraft, the American Magellan also visited Venus. He produced an almost complete mapping of the planet. During the scanning process, a huge number of volcanoes, hundreds of craters and numerous mountains were discovered. Based on their characteristic elevations, relative to the average level, scientists have identified 2 continents - the land of Aphrodite and the land of Ishtar. On the first continent, the size of Africa, there is an 8-kilometer Mount Maat - a huge extinct volcano. The continent of Ishtar is comparable in size to the United States. Its attraction is the 11-kilometer Maxwell Mountains, the highest peaks on the planet. The composition of the rocks resembles terrestrial basalt.
On the Venusian landscape, impact craters filled with lava can be found with a diameter of about 40 km. But this is an exception, because there are about 1 thousand of them in total.

Characteristics of Venus

Weight: 4.87*1024 kg (0.815 earth)
Diameter at the equator: 12102 km
Axle tilt: 177.36°
Density: 5.24 g/cm3
Average surface temperature: +465 °C
Period of rotation around the axis (days): 244 days (retrograde)
Distance from the Sun (average): 0.72 a. e. or 108 million km
Orbital period around the Sun (year): 225 days
Orbital speed: 35 km/s
Orbital eccentricity: e = 0.0068
Orbital inclination to the ecliptic: i = 3.86°
Gravity acceleration: 8.87m/s2
Atmosphere: carbon dioxide(96%), nitrogen (3.4%)
Satellites: no

We've been studying the solar system for hundreds of years, and you'd think we'd have answers to every frequently asked question about it. Why do the planets rotate, why are they in such orbits, why does the Moon not fall to the Earth... But we cannot boast of this. To see this, just look at our neighbor, Venus.

Scientists began to study it closely in the middle of the last century, and at first it seemed relatively dull and uninteresting. However, it soon became clear that this is the most natural hell with acid rain, which also rotates in the opposite direction! More than half a century has passed since then. We've learned a lot about Venus's climate, but we still haven't figured out why it spins differently than everyone else. Although there are many hypotheses on this matter.

In astronomy, rotation in the opposite direction is called retrograde. Since all solar system formed from one rotating gas cloud, all the planets move in orbits in the same direction - counterclockwise, if you look at this whole picture from above, from the side north pole Earth. In addition, these celestial bodies also rotate around their own axis - also counterclockwise. But this does not apply to the two planets of our system - Venus and Uranus.

Uranus is actually lying on its side, most likely due to a couple of collisions with large objects. Venus rotates clockwise, and this is even more problematic to explain. One early hypothesis suggested that Venus collided with an asteroid, and the impact was so strong that the planet began to spin in the other direction. This theory was introduced to the public in 1965 by two astronomers processing radar data. Moreover, the definition of “thrown in” is in no way a derogation. As the scientists themselves stated, quote: “This possibility is dictated only by imagination. It is hardly possible to obtain evidence to support it.” Extremely convincing, isn't it? Be that as it may, this hypothesis does not stand up to the test of simple mathematics - it turns out that an object whose size is sufficient to reverse the rotation of Venus will simply destroy the planet. Its kinetic energy will be 10,000 times greater than what is needed to smash the planet into dust. In this regard, the hypothesis was sent to the distant shelves of scientific libraries.

It was replaced by several theories that had some kind of evidence base. One of the most popular, proposed in 1970, suggested that Venus originally rotated this way. It’s just that at some point in its history it turned upside down! This could have happened due to processes occurring inside Venus and in its atmosphere.

This planet, like the Earth, is multi-layered. There is also a core, mantle and crust. As the planet rotates, the core and mantle experience friction in the area of ​​their contact. The atmosphere of Venus is very thick, and, thanks to the heat and gravity of the Sun, it is subject, like the rest of the planet, to the tidal influence of our star. According to the described hypothesis, friction between the crust and the mantle, coupled with atmospheric tidal fluctuations, created a torque, and Venus, losing stability, capsized. Simulations showed that this could only happen if Venus had an axis tilt of about 90 degrees from the moment of its formation. Later this number decreased somewhat. In any case, this is a highly unusual hypothesis. Just imagine - a tumbling planet! This is some kind of circus, not space.

In 1964, a hypothesis was put forward according to which Venus changed its rotation gradually - it slowed down, stopped, and began to spin in the other direction. This could be caused by several factors, including interaction with magnetic field The sun, atmospheric tides, or a combination of several forces. The atmosphere of Venus, according to this theory, spun in the other direction first. This created a force that first slowed down Venus and then spun it retrograde. As a bonus, this hypothesis also explains the long length of the day on the planet.

In the debate between the last two, there is no clear favorite yet. To understand which one to choose, we need to know much more about the dynamics of early Venus, in particular about its rotation speed and axis tilt. According to a 2001 paper published in the journal Nature, Venus would be more likely to capsize if it had a high initial rotation speed. But, if it was less than one revolution in 96 hours with a small axial tilt (less than 70 degrees), the second hypothesis looks more plausible. Unfortunately, it is quite difficult for scientists to look back four billion years. Therefore, until we invent a time machine or conduct unrealistically high-quality research today computer simulations, no progress is expected on this issue.

It is clear that this is not Full description discussions regarding the rotation of Venus. For example, the very first of the hypotheses we described—the one that dates back to 1965—received an unexpected development not long ago. In 2008, it was suggested that our neighbor could have spun in the opposite direction at a time when she was still a small, unintelligent planetesimal. An object approximately the same size as Venus itself must have crashed into it. Instead of the destruction of Venus, there would be a merger of the two celestial bodies into one full-fledged planet. The main difference from the original hypothesis here is that scientists may have evidence in favor of such a turn of events.

Based on what we know about the topography of Venus, there is very little water on it. Compared to Earth, of course. The moisture could have disappeared from there as a result of a catastrophic collision cosmic bodies. That is, this hypothesis would also explain the dryness of Venus. Although there is also, how ironic it is in in this case did not sound, pitfalls. Water from the surface of the planet could simply evaporate under the rays of the hot Sun here. To clarify this issue, a mineralogical analysis of rocks from the surface of Venus is needed. If water is present in them, the hypothesis of an early collision will disappear. The problem is that such analyzes have not yet been carried out. Venus is extremely unfriendly to the robots we send to it. Destroys without any hesitation.

Be that as it may, building an interplanetary station with a Venus rover capable of working here is still easier than a time machine. Therefore, let's not lose hope. Perhaps humanity will receive an answer to the riddle about the “wrong” rotation of Venus in our lifetime.