As the second planet of the sun, Venus is often called the Earth's "sister planet" because of its similar size, mass, and bulk composition. However, although it may seem similar to Earth from a distant point of view, the case could not be more different from close. the atmospheric pressure on the surface of the planet, it is 92 times higher than that of the Earth, approximately the pressure found at 900 m below the surface of the ocean.
Venus is by far the hottest planet in the solar system, with an average surface temperature of 500 ° C even though Mercury is closer to the sun.
However, things could not have been more different after the birth of the solar system, revealed Brian Cox during his new BBC series "The Planets".
He said in May: "The current surface temperatures on Venus are warmer than those on Mercury.
"And the history of the climate of Venus is further complicated by the fact that throughout the life of the planet, the Sun itself has evolved.
Venus had flowing rivers in her distant past
Brian Cox revealed the discovery of NASA
Rivers of water flowed and Venus became an oceanic world
"As the Sun ages, the star burns hotter and hotter.
"This means that in the past, when the sun was younger, it must be colder and it has a big impact on the planets."
Dr. Cox then revealed how a cooler and wetter Venus possessed all the properties needed to support life.
He added, "By the time life was just beginning on Earth, three and a half to four billion years ago, the Sun was paler and that meant Venus was colder.
"In fact, the temperatures on Venus at that time would have been like a nice spring day on Earth.
"A few million years after its formation, the surface of Venus has cooled down and the planet has found itself at the right distance from the young Sun to allow Venus to live a vision that is familiar to us here on Earth.
"The sky is open and large torrents have flooded the surface, rivers of water have flowed and Venus has become an oceanic world.
"The atmosphere of the planet has allowed it to conserve the oceans by acting as a blanket, maintaining the temperature of the surface through the greenhouse effect."
Dr. Cox also revealed in the same series how an extraterrestrial life could also flourish on Titan, Saturn's moon, in the future.
He explained: "The Cassini [satellite] remains in orbit around Saturn and one year after landing, Huygens flies over Titan's North Pole and discovers something not seen anywhere else in the solar system.
Venus is the second planet of the sun
Venus began to cool with time
"Liquid reserves are not just one, but dozens of large lakes.
"Cassini discovered lakes of liquid methane and the Earth has a strange cold twin.
"What is also fascinating, and in fact very tempting, is that Titan has a complex chemistry and that chemistry is carbon chemistry – the chemistry of life."
Dr. Cox then explained how this chemistry could make life possible on the moon.
He added: "We have therefore found molecules such as hydrogen cyanide, which is the cornerstone of the amino acids, molecules called vinyl cyanide, that chemists and biologists think could form a molecule. kind of cell membrane.
"And all the ingredients of life are present on Titan.
"At present, very few scientists think that there will be life on Titan today. After all, it's -180 ° C on the surface.
"But because of the presence of all these ingredients, it could be a very different story if you warm Titan."
In about 5.5 billion years, the Sun will arrive at the end of its current life cycle, it will come out of the main sequence and become a red giant engulfing Mercury, Venus and possibly Earth as well.
It should then increase and double in size and power, which means that sunlight will reach the far corners of the solar system.
Dr. Cox explained how this could trigger something special for Titan.
He continued: "In light of the old expanding Sun, the more remote regions of the Solar System will receive more solar energy.
"Titan's atmosphere will begin to warm up.
"Mountains of ice will shrink and melt as temperatures rise, the iced water they contain replaces liquid methane.
"The mountains will become oceans of water and, in a strange twist of fate, at the end of the Sun's life, the last oceanic world of the solar system will wake up with its own biological possibilities."