The Size of Our Local Area

British spelling.

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Now it is time to use our imagination.

Our solar system seems massive to us but is very small when we compare it to our galaxy, the Milky Way, and is minuscule when we think of the universe as a whole.

To make the distances within the solar system easier to comprehend, I will use the speed of a Boeing 737 aircraft; that speed is roughly 800 kilometres or 500 miles per hour.

We all know that the Moon is our closest celestial body; it has been the Earth's companion for just over 4.5 billion years. The Moon has an age that is slightly younger than that of the Earth.

Considering the size of our solar system, the moon is just a step away, at 384,000 kilometres, or 238,000 miles. That very short flight for our fictional journey would take 20 days.

It has been over 50 years since men went to the moon and walked on its surface.

The next space journey for us humans might be the Moon again, or will it be planet Mars?

Mars, the fourth planet from the Sun, can be as close as 54 million kilometres, or 33 million miles, from the Earth, but it can also be much farther away. We will base our flight to Mars on that lower number.

This is still a very short distance within the solar system and would take our aircraft almost eight years to arrive at Mars.

Pluto was discovered in 1930 and was known as the 9th planet for 76 years, but in 2006, the International Astronomical Union (IAU) downgraded the status of Pluto to a dwarf planet.

That left the Sun with eight orbiting planets. Pluto is much farther away from the Sun than the most distant planet, Neptune.

This will be a much longer flight for our imaginary aircraft. At its closest point to the Earth, Pluto would still be 4.28 billion kilometres, or 2.7 billion miles away.

Using that distance, our fictional aircraft would take 610 years to reach Pluto.

The size of the solar system does not end there; there is thought to be a cloud of icy objects that surrounds the sun, and the closest edge of the Oort cloud could be 2,000 astronomical units away.

One astronomical unit is the distance between the Sun and the Earth; that average distance is over 149 million kilometres or 92 million miles.

For our Boeing 737 to reach the closest edge of the Oort cloud would take over 42,000 years.

Higher estimates place the outer edge of the Oort cloud at 200,000 astronomical units away from the Sun. Now our flight time gets silly; that long journey for our Boeing aircraft would take over 4 million years. Wow!

Our galaxy, the Milky Way, is estimated to be over 100,000 light-years in diameter. Now consider this fact: light travels at 1,080 million kilometres, or 671 million miles per hour, and yes, there are a lot of hours in 100,000 years. That makes you realise how massive our galaxy is.

Arguably, the solar system is one light-year in diameter, so it could be said that our galaxy, the Milky Way, is over 100,000 times wider than the solar system.

One estimate for the number of galaxies in the universe is 2,000,000,000,000; that's 2 trillion.

With highly advanced telescopes, we can now see galaxies that are over 13 billion light-years away.

I hope that this short article has put the size of our solar system into some sort of perspective; it is indeed tiny in comparison to our galaxy.

The size of the solar system in comparison to the universe is unfathomable; it is beyond minuscule.

The end.

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