If you’re standing on Earth’s surface, it is simple to forget that our planet is hurtling across the sun at greater than 67,000 mph (107,800 km/h). And it’s even easier to forget that there are seven other planets also making their way around our home star at similar breakneck speeds, or that every one eight have been ceaselessly circling the solar system for billions of years.
But what might really blow your mind is checking out what number of trips across the sun each planet has under its belt. This will seem to be a tough thing to calculate, but since the planets’ orbits have remained largely unaltered for many of their existence, all it takes is a little bit of basic math.
Related: What is the maximum variety of planets that might orbit the sun?
The solar system was born around 4.6 billion years ago, when the sun began to form from a cloud of dust left behind by prior stellar explosions. Around 4.59 billion years ago, the enormous planets — Jupiter, Saturn, Uranus and Neptune — were born. And around 4.5 billion years ago, the smaller, rocky planets — Mercury, Venus, Earth and Mars — took shape, in accordance with The Planetary Society.
But when the planets were born, their orbits across the sun weren’t the identical as they’re today (especially those of the enormous planets). For around 100 million years after the primary planets formed, there was a “dynamical instability” amongst them, which resulted in a gravitational tug-of-war between these large bodies and caused the remainder of the outer solar system’s planetary material, and even some emerging protoplanets, to be catapulted out of the solar system, Sean Raymond, an astronomer on the Bordeaux Astrophysics Laboratory in France and an authority on planetary systems, told Live Science in an email.
Nevertheless, once all the planets had emerged and finished jostling with each other for his or her positions, they settled into consistent, stable orbits that have not modified much since.
“For 98% to 99% of the solar system’s lifetime, the planets’ orbits have been nice and stable,” Raymond said. Because of this, you need to use the planets’ current orbital dynamics to make a fairly accurate guess at what number of trips they’ve made across the sun, he added.
Take Earth, for instance. Our planet takes a 12 months to orbit the sun and has existed for 4.5 billion years, so it has taken roughly 4.5 billion trips across the solar system.
Nevertheless, the variety of total orbits varies greatly among the many other planets because their years are either shorter or longer than Earth’s.
Mercury, the closest planet to the sun, takes only 88 days (or roughly 0.24 years, based on a 12 months with 365.25 days) to travel across the sun once. So, over the past 4.5 billion years, it has accomplished around 18.7 billion solar orbits. But Neptune, the farthest planet from the sun, takes around 60,190 days (or 164.7 years) to finish an orbit, which implies it has managed only about 27.9 million trips across the sun during its 4.59 billion years of existence. Which means Mercury has orbited the sun around 18.7 billion times greater than Neptune has.
Here is the complete list of the planets, their 12 months length and their total variety of trips across the sun:
Planet | Age (in billions of years) | Orbital period (in days) | Variety of total orbits |
---|---|---|---|
Mercury | 4.5 | 88 | 18.7 billion |
Venus | 4.5 | 225 | 7.3 billion |
Earth | 4.5 | 365.25 | 4.5 billion |
Mars | 4.5 | 687 | 2.4 billion |
Jupiter | 4.59 | 4,333 | 386.9 million |
Saturn | 4.59 | 10,759 | 155.8 million |
Uranus | 4.59 | 30.687 | 54.6 million |
Neptune | 4.59 | 60,190 | 27.9 million |
These sound like impressive numbers (they usually are) but a lot of the planets could potentially double their variety of orbits of their remaining lifetimes.
In around 4.5 billion years, the sun can have swollen outward to achieve Earth’s orbit and transition right into a red dwarf star, which is able to destroy Mercury, Venus and Earth. The opposite planets may live to tell the tale for a time in the event that they are usually not burned up but their orbits will likely be majorly altered.