There was a time when the Universe had no light.

The Cosmic Dark Ages.

Image credit. Dirk Wouters Pixabay.

British spelling.

The Universe came into existence about 13.8 billion years ago, but there were no stars at that time.

Look at the image above, can you imagine space with no light?

Most of us are familiar with the night sky. We look up and see the Moon. We can also see some of the planets and of course we can view the stars.

But space has not always been like that. It took about 200 million years after the big bang (the birth of the Universe) for stars to form and shine.

Surprisingly, we can also see the Andromeda galaxy with unaided eyes. The Andromeda galaxy is over 2.5 million light-years away.

Imagine, for every hour of that 2.5 million years, the light from that galaxy has travelled 1,080 million kilometres towards us.

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The Reason For A Leap Year.

Image credit, Thomas Bormans Unsplash.

Our planet Earth takes 24 hours to make a full rotation on its axis. We call that time period a day.

We are all aware that there are 365 days in our calendar year, but a solar year is actually 365 days, 5 hours, 48 minutes, and 46 seconds, which is the exact time the Earth takes to make a complete circuit or orbit around the Sun.

That is the reason a time adjustment is needed, and a leap day is added to the end of February every 4 years. You will know it as a leap year.

That additional leap day is added to keep the calendar year synchronised with a solar year.

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Evolution, Or Not?

Image credit, Church of the King Unsplash.

You are a highly advanced life form, but why has this happened? Why are you here?

Consider yourself very special and unique, the odds against your existence are astronomical.

Evolutionary biologists agree that humans and other living species are descended from simple bacteria-like ancestors.

Bacteria can be traced back at least 3.5 billion years. Over countless generations, small modifications have taken place, and the small changes that are more favourable to life are more likely to be passed on to the next generation. This has been happening since the first life appeared on our planet.

This very long process is called natural selection, which is thought to be the reason you are here. We are the latest result of an unbroken chain of life that started billions of years ago.

Life is amazing, but it must be said that it is not yet fully understood why life got a start on our magical planet, but we have a good idea of how it has evolved.

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What colours do dogs see?

Shutterbug75 from Pixabay.

My dog Kobi will not see red tomatoes the way we see them, to a dog a red tomato would appear brownish-grey.

Cones are photoreceptors cells concentrated in the centre of the retina in our eyes and are responsible for colour vision.

Unlike humans with three types of cones, dogs, cats, and most mammals have only 2 types of cones, the missing one being red.

Other animals including insects can have poorer or much better sight than we have, some can see parts of the light spectrum that we cannot see.

Some animals have no eyes, like the star-nosed mole, Texas blind salamander or the Mexican tetra. They have evolved this way because they live out their lives in pitch-black surroundings, like in caves, beneath the ground, or in the ocean's depths.

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Galaxies are massive objects.

Arnaud Mariat Unsplash.

Galaxies are massive objects holding millions or billions of stars, all held together by gravity.

There are three major types of galaxies the first being a spiral galaxy like our own galaxy, the Milky Way. Most spiral galaxies consist of a flat rotating disk of stars with a bulge in the centre which contains a large concentration of stars.

Another type is an elliptical galaxy which has the shape of an elongated sphere.

An irregular galaxy is the third and it has no regular or symmetrical structure.

It is estimated that there are 2 trillion galaxies in the observable Universe, each one, on average, containing about a hundred million stars.

Yes, the Universe is an enormous place, maybe too large for our minds to comprehend.

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You might enjoy reading some of my easy-to-understand articles regarding the Universe and Life.

Free reads.