Your age on other planets
On Mercury you would already be ancient, and on Neptune you would not even be one yet. Find out your age on each planet and how many days you have lived.
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Why is your age different on each planet?
A year is the time a planet takes to go once around the Sun. The farther away it is, the longer its orbit and the slower it moves, so its year lasts longer. Mercury completes a lap in just 88 Earth days, while Neptune needs almost 165 years: since it was discovered in 1846, it has barely completed one orbit.
age on a planet = days lived / length of the planet’s year (in days)
Johannes Kepler found the rule behind it in 1619: the square of the orbital period is proportional to the cube of the distance from the Sun (T² ∝ a³). That is why Jupiter, about 5 times farther away than Earth, takes almost 12 years to go around.
Where do the other figures come from?
They are estimates based on averages: about 100,000 heartbeats and 20,000 breaths a day, a third of the time asleep, a full moon every 29.53 days and about 940 million kilometers traveled on each trip of the Earth around the Sun, at roughly 107,000 km/h (67,000 mph).
Frequently asked questions
How long is a year on each planet?
In Earth days or years: Mercury, 88 days; Venus, 225 days; Mars, 687 days (1.88 years); Jupiter, 11.9 years; Saturn, 29.5 years; Uranus, 84 years; and Neptune, almost 165 years. The farther from the Sun, the longer the orbit and the slower the planet travels along it.
How old would I be on Mars or Mercury?
Divide your age by the length of the planet’s year in Earth years. A 30-year-old would be about 16 in Martian years, because a year on Mars lasts 1.88 Earth years, and about 125 on Mercury. On Jupiter they would only just be two and a half.
When will I turn 10,000 days old?
Ten thousand days is about 27 years and four and a half months. At 30 you have lived about 10,957 days, and 20,000 days come shortly before your 55th birthday. Enter your date of birth in the tool to see the exact number of days you have lived so far.
Is it true that a day on Venus is longer than its year?
Yes. Venus spins so slowly, and in the opposite direction to most planets, that it takes 243 Earth days to turn once on its axis, while its year lasts 225. Because rotation and orbit combine, the time from one sunrise to the next on Venus is about 117 Earth days.