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These Amazing Space Journeys Are Incredible

Comets are lonely space travellers who infrequently visit the sun.

By A B ForbesPublished 2 months ago 3 min read
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These Amazing Space Journeys Are Incredible
Photo by Justin Wolff on Unsplash

British spelling.

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About 27 years ago, I was on a fishing boat travelling from Scotland to Norway.

It was April 1997. The mate of the boat, who, like myself, had an interest in astronomy, called me in the middle of the night.

The sea was calm, and with no clouds, the sky was clear, which was unusual for the North Sea. At the top of the bridge, we lay down and looked up at the night sky, and there it was: Comet Hale-Bopp.

We had viewed the comet on previous nights, but this was different. The comet and the stars looked so bright, so why was the visibility so good? Even the odd shooting star (meteor) streaked across the crystal-clear sky.

The celestial bodies were easy to see because of the lack of light; without the light pollution, it was complete darkness.

Image credit. Jeremy Bishop on Unsplash

This must have been similar to the clear skies our ancestors viewed long before we had towns and cities illuminated by light. Of course, we have come to depend on that artificial light.

Although Hale Bopp and its long, flowing tail appeared bright in the night sky, it was 197 million kilometres, or 122 million miles, from the Sun at its closest approach.

Comets are dirty cosmic snowballs, leftover from the formation of the solar system roughly 4.6 billion years ago.

They are made of ice, rocks, and frozen gases. As they approach the sun, they warm up and release water vapour and gases that stream away from the nucleus. This is what we call a comet’s tail; the tail can stretch away from the sun for millions of kilometres.

Comets have highly eccentric elliptical orbits or oval-shaped paths. Comets close to the sun can leave a trail of debris behind them, which can lead to meteor showers as they enter the earth’s atmosphere and burn, leaving streaks of light behind them.

Short-period comets take 200 years or less to make one orbit around the Sun; long-period comets can take much longer, and some take millions of years to complete one journey around our local star, the Sun.

We know that short-period comets originate from a band of icy objects known as the Kuiper belt, which lies farther out than Neptune’s orbit. Among the eight planets in the Solar System, Neptune is the farthest from the Sun.

The Oort cloud is a distant spherical region containing trillions of icy bodies that circle the sun. Long-period comets are thought to originate from that area of space.

The start of the Oort cloud could be 100,000 times the distance between the Sun and the Earth. So it is no surprise that some long-period comets can take millions of years to complete one orbit around the Sun.

The distance between the sun and the earth is called an astronomical unit, or an AU.

In 1986, my two young children and I watched the short-period comet Halley as it made its closest approach to the Sun on its long elliptical journey through space.

My children may see it again. In 2023, in an area of space farther away than Neptune, Halley’s comet will turn around and start on that long trek back towards the Sun, arriving here in 2061.

Depending on when you were born, some people will see Halley’s comet twice in their lifetime. I saw it once but will never see it again.

Image credit. JULIAN WINFIELD on Unsplash.

Comet Halley was named after English astronomer Edmond Halley.

Comets are usually named after the people who discovered them. Comet Shoemaker-Levy 9 was named after Eugene and Carolyn Shoemaker and David Levy.

No one will ever see that comet again. Shoemaker-Levy 9 entered Jupiter’s atmosphere in July 1994, providing the first direct observation of a comet impacting a solar system object.

Astronomers have found what could be the largest comet ever seen; it is named Bernardinelli-Bernstein. It has an estimated diameter of between 100 and 200 kilometres and will make its closest approach to the Sun in 2031, there is no need to be alarmed; the closest it will get to the Earth will be roughly 1.6 billion kilometres or 1 billion miles.

Throughout recorded history, people have looked up at the night sky and witnessed comets, meteor showers, eclipses, and a few supernovae. It could have been fascinating for some and terrifying for others.

But now we have a far better understanding of our solar system and that gargantuan area we call the universe.

The end.

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You may find my easy-to-understand stories about the universe and life interesting and educational.

If you subscribe to me for free, you will see my latest stories. Regards.

travelspacesciencehumanityastronomy
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About the Creator

A B Forbes

Someone with a lifelong passion for that gargantuan area we call the universe. I also write stories about life itself. Enjoy

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