The most dangerous planet for human beings in our solar system is undoubtedly Venus. There are several reasons why Venus is inhospitable and hazardous to humans:
Extreme Surface Temperature: Venus has an average surface temperature of around 467 degrees Celsius (872 degrees Fahrenheit). This is hotter than the surface of Mercury, which is the closest planet to the Sun. The high temperatures are a result of a runaway greenhouse effect caused by its thick atmosphere, which traps heat and keeps the planet scorching hot.
Atmospheric Pressure: The atmospheric pressure on Venus is about 92 times greater than that of Earth. It is equivalent to the pressure experienced 900 meters (2953 feet) underwater on Earth. The crushing pressure would be deadly to humans.
Toxic Atmosphere: Venus's atmosphere is predominantly composed of carbon dioxide with traces of sulfuric acid clouds. The thick atmosphere also leads to a strong greenhouse effect, making the surface temperature unbearable.
Lack of Oxygen: Venus has virtually no oxygen in its atmosphere. It consists mainly of carbon dioxide, nitrogen, and other gases that are toxic to humans.
Due to these extreme conditions, Venus is not a viable place for human habitation, and any attempts to land on the surface would be challenging and likely unsuccessful without specialized and heavily shielded equipment.
As for other planets in our solar system, none of them are habitable for humans without extensive life support systems. Mars, often considered the most "Earth-like" planet, has a thin atmosphere, extreme temperatures, and no readily available liquid water. The gas giants like Jupiter and Saturn lack solid surfaces, and their atmospheres are composed mostly of hydrogen and helium, which are not conducive to human life.
Beyond our solar system, scientists have not yet discovered any planets that could support human life without significant technological advancements and adaptations. The search for potentially habitable exoplanets is ongoing, but currently, there is no definitive evidence of planets that have conditions suitable for human habitation without significant modifications and life support systems.