The planets in our solar system are extremely varied, ranging from Venus, where temperatures can reach a scorching 471°C, to Neptune, where it plummets to a chilly -201°C. As well as varying in temperature, the planets also have different motions, meaning the length of a day and a year is very different. Now, Exploratorium has put together a handy calculator that lets you see just how old you would be on the other planets.
Simply enter your date of birth, and the calculator will reveal your age in days and years, as well as when your next birthday would be. For example, my birthday is 4 January 1992, meaning that here on Earth I’m 28. However, on Mercury, I would be 118.9 years old and my next birthday would be on September 1 2020, while on Neptune I’d be just 0.17 years old, and my next birthday wouldn’t be until Aug 11 2240! To understand why this is the case, it’s helpful to know how a day and year are actually defined.
Exploratorium explained: “The Earth is in motion. Actually, several different motions all at once. There are two that specifically interest us. First, the Earth rotates on its axis, like a spinning top. Second, the Earth revolves around the sun, like a tetherball at the end of a string going around the centre pole.”
A day is defined by the time it takes for the top-like rotation of the Earth on its axis.
Exploratorium said: “There are no rules that govern the rotation rates of the planets, it all depends on how much "spin" was in the original material that went into forming each one. Giant Jupiter has lots of spin, turning once on its axis every 10 hours, while Venus takes 243 days to spin once.”
Meanwhile, the revolution of the Earth around the sun is how we define a year.
Exploratorium added: “While Earth takes 365 days to make one circuit, the closest planet, Mercury, takes only 88 days. Poor, ponderous, and distant Pluto takes a whopping 248 years for one revolution.”