- 4267 - EARTH TRIPS - around the Sun ? - How many times has Earth orbited the sun? Most people are stumped with that question. How many trips each of the solar system's eight planets has taken around the sun over the past 4.6 billion years and what will in total is more complicated.
------------------ 4267 - EARTH TRIPS - around the Sun ?
- When you're
standing on Earth's surface, it's easy to forget that our planet is hurtling
around the sun at more than 67,000 miles per hour. 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 all eight have been ceaselessly
circling the solar system for billions of years.
-
- Because the
planets' orbits have remained largely unaltered for most of their existence,
all it takes is a bit of basic math.
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 giant planets, Jupiter, Saturn, Uranus and Neptune, were
born. And around 4.5 billion years ago, the smaller, rocky planets, Mercury,
Venus, Earth and Mars, were born.
-
- But when the
planets were born, their orbits around the sun were not the same as they are
today (especially those of the giant planets). For around 100 million years
after the first planets formed, there was a "dynamical instability"
among them, which resulted in a gravitational tug-of-war between these large
bodies and caused the rest of the outer solar system's planetary material, and
even some emerging protoplanets, to be catapulted out of the solar system.
-
- However, once all
of the planets had emerged and finished jostling with one another for their
positions, they settled into consistent, stable orbits that haven't changed
much since.
-
- For 98% to 99% of
the solar system's lifetime, the planets' orbits have been stable. As a result,
you can use the planets' current orbital dynamics to make a pretty accurate
guess at how many trips they have made around the sun.
-
- The Earth takes a
year to orbit the sun and has existed for 4.5 billion years, so it has taken
roughly 4.5 billion trips around the solar system.
-
- However, the
number of total orbits varies greatly among the 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 year with 365.25 days) to travel around the sun once. So, over the past 4.5
billion years, it has completed around 18.7 billion solar orbits.
-
- But Neptune, the
farthest planet from the sun, takes around 60,190 days (or 164.7 years) to
complete an orbit, which means it has managed only about 27.9 million trips
around the sun during its 4.59 billion years of existence. That means Mercury
has orbited the sun around 18.7 billion times more than Neptune has.
-
Planet Age (in billions
of years) Orbital period (in
days) Number 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
-
- Most of the
planets could potentially double their number of orbits in their remaining
lifetimes.
-
- In around 4.5
billion years, the sun will have swollen outward to reach Earth's orbit and
transition into a red dwarf star, which will destroy Mercury, Venus and Earth.
The other planets may live on for a time if they are not burned up but their
orbits will likely be majorly altered.
-
-
December 11, 2023 EARTH TRIPS
- around the Sun ? 4267
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