Venus

Venus

Venus is the second planet in the solar system in terms of distance from the Sun.
This planet has an almost circular orbit which leads it to complete one revolution in 225 Earth days.
The term Venus derives from the Roman goddess of love and beauty and her astronomical symbol is the stylized representation of Venus’ hand holding a mirror.
It is classified as a terrestrial planet, however in other respects it is quite different from our planet. Venus’ atmosphere consists mainly of carbon dioxide and is much denser than Earth’s atmosphere, with a pressure at ground level of 92 atm. The density and composition of the atmosphere create an impressive greenhouse effect that makes Venus the hottest planet in the solar system.
In fact, this planet is surrounded by a thick layer of highly reflective clouds, composed mainly of sulfuric acid, which prevent vision in the visible spectrum of the surface from space. The planet has no satellites or rings and has a weaker magnetic field than Earth’s.

Astronomical Observation –
The planet Venus, with a maximum magnitude of −4.6, is the brightest natural object in the night sky after the Moon and for this reason has been known since ancient times. Venus is visible only shortly after sunset and shortly before dawn and for this reason it was often called the evening star or morning star by the ancient Greeks (and later by the Romans). The discovery that it is the same object was introduced to the West by Pythagoras, but it was due to the astronomers of Mesopotamia. In fact, in the Venus Tablet of Ammi-Saduqa there are observations dating back to 1550 BC. or antecedents, in which no distinction is made between the morning star and the evening star.
Even today, astronomical observation of Venus is an interesting activity for astronomy enthusiasts, as Venus is one of the brightest and most visible planets in the night sky.
Venus, as mentioned, is often called the “evening star” or the “morning star” because it is visible shortly after sunset or just before sunrise, depending on its position relative to the Sun. When it is the “evening star” “, is found to the west of the Sun, while when it is the “morning star”, it is found to the east of the Sun.
Venus can be observed with the naked eye, but an instrument such as binoculars or a telescope allows you to see surface details of the planet. Venus goes through phases similar to those of the Moon, going from a small crescent to full and then back to crescent. This is especially visible through a telescope.
To spot Venus in the sky, you will have to know where to look. Astronomy planning tools or smartphone apps can help determine when and where Venus will be visible in your location.
When Venus is visible near the Sun, care must be taken not to look directly at the Sun through a telescope or binoculars without adequate solar filters. This could cause permanent damage to your vision. It is therefore advisable to always use certified sun filters to observe the Sun or wait until Venus is sufficiently separated from its position.
We must try to observe Venus in a place with the least light pollution possible. Dark places away from city lights are ideal for astronomical observations.
By observing Venus through a telescope, you can see its phases, similar to those of the Moon. Venus goes from a small crescent to a crescent phase, then to a gibbous phase, until it becomes a small crescent again. These phases change over the months, depending on the relative position of Venus with respect to the Sun.
Sometimes, Venus passes in front of the Sun in an event called a Venus transit. Such transits are rare and occur in pairs, with approximately 8 years of separation between them, followed by over a century of absence. The last transit of Venus occurred in 2012, and the next one will be in 2117. These events are notable and require specific precautions for observation.
Astronomical observation of Venus can be a fascinating and educational experience for astronomy enthusiasts. But make sure you plan your observations in advance and use the right tools to get the best possible view of this brilliant planet.

Physical characteristics –
Venus has a diameter of approximately 12,104 kilometers, which is approximately 95% of the size of Earth. However, due to its dense atmosphere and extreme conditions on the surface, it is often considered the planet most similar to Earth in size, but very different in environmental conditions.
Venus’ atmosphere is very dense and composed mainly of carbon dioxide (CO2) with traces of nitrogen and sulfuric acid. The atmospheric pressure on the surface of Venus is about 92 times that of Earth, making the atmosphere extremely oppressive.
Venus has one of the warmest surface temperatures of all the planets in the solar system. Due to the greenhouse effect caused by the thick atmosphere, the average surface temperature is about 465 degrees Celsius (869 degrees Fahrenheit), hotter than Mercury despite being farther from the Sun.
The surface of Venus is characterized by vast volcanic plains, high mountains and numerous craters. There are also regions of high volcanic activity with rivers of solidified lava. The surface of Venus is extremely dry and rocky, with no evidence of liquid water.
Venus rotates very slowly and retrogradely compared to most other planets. Its solar day, the time it takes to make a complete rotation, lasts longer than its year, and is approximately 117 Earth days.
This planet has a relatively low crater density compared to Mercury, the Moon or Mars. This is due to its dense atmosphere, which protects the surface from small meteorite impacts.
The surface of Venus is very bright, with a high albedo due to reflection of sunlight. This helps make the planet visible to the naked eye from Earth as one of the brightest celestial bodies in the night sky.
Overall, Venus is an extremely inhospitable planet, with scorching temperatures, oppressive atmospheric pressure, and a chemical composition that makes life as we know it impossible. Its thick atmosphere and surface conditions make direct exploration very difficult, but space missions, such as the Soviet Venera mission and NASA missions, have provided valuable information about Venus’ surface and atmosphere.

Space missions –
Space missions to Venus have been conducted by various space agencies over the years. Venus is an Earth-like planet in size, but its surface conditions are extremely hostile, with an average surface temperature of more than 450 degrees Celsius, extremely high atmospheric pressure, and sulfuric acid rain. These conditions make direct exploration of the planet very difficult.
Among these missions we remember the following:
1. Venera Program (Soviet Union): In the 1960s and 1970s, the Soviet Union conducted a series of Venera missions that allowed probes to be sent to the surface of Venus. These probes sent back data on the composition of the atmosphere and the surface of the planet. The Venera 7 probe was the first to transmit data from the surface of Venus in 1970.
2. Magellan (NASA): The Magellan mission, led by NASA, sent a radar orbit around Venus in the 1990s. This mission mapped the surface of Venus using radar, collecting data on the planet’s topography and geology.
3. Akatsuki (JAXA): The Japanese probe Akatsuki was launched in 2010 and was placed into orbit around Venus in 2015. Its main mission is to study Venus’ atmosphere, particularly its meteorological phenomena.
4. Veritas (NASA): The Veritas mission was announced by NASA in 2020 and aims to map the surface of Venus with an advanced synthetic aperture radar and study the planet’s topography and geology.
It is important to note that the exploration of Venus is extremely challenging due to its extreme conditions, but continues to attract scientific interest. Future missions could seek to better understand the planet’s climatic evolution and answer questions about its geology, the possibility of volcanic activity and the history of water on Venus.

Guido Bissanti