A lifespan can be extremely long or very short.

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A mayfly is a small flying insect that lives around lakes, ponds, and streams in North America. An adult mayfly will live less than 24 hours.

Mice like the ones you see around your home have very short lives, living in the wild, their lifespan is roughly one year.

An average human lifespan is described as three score years and ten, which is 70. I am over that age, so I suppose every year now is a bonus for me.

Bowhead whales can live over 200 years.

One organism, the bristlecone pine tree can live for a very long time. An unnamed tree still alive today has an estimated age of over 5,000 years. It grows in the White Mountains of California.

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How far have our radio signals gone?

Image credit. Alessandro Cerino Unsplash

The first radio broadcast was transmitted around 1920, radio waves travel at the same speed as visible light, an incredible 1,080 million kilometres per hour.

Those early signals are still travelling through space, and are now 955 trillion kilometres from the Earth.

If an intelligent alien life form detected them now and sent a signal back, we would have to wait over 100 years for a reply.

Imagine a sphere 200 light-years in diameter with the Earth at the centre, that is how big a footprint our radio signals have in space.

Now imagine the size of that sphere inside our galaxy, which has a diameter of well over 100,000 light-years.

Considering the vast distances, you can understand why we have never heard from extraterrestrials.

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Homo Sapiens rule the world.

Image credit. Capri23auto Pixabay.

Our early ancestors existed in east Africa six million years ago.

Primitive life on our planet can be traced back at least 3.5 billion years.

Humans, known as Homo Sapiens have been around for roughly 200,000 years. Civilisation as we know it has existed for 6,000 years.

The evolutionary path for life on Earth has been very long, but at last, we have finally arrived.

Some animals have evolved to be stronger, larger and faster than we are and some can fly. Many never leave the water, but what sets us apart is that we have developed the most advanced brain.

That amazing brain has given us intelligence, curiosity, and the ability to carry out the science which is providing a better understanding of our world and life itself.

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The predictable tides.

Image credit. Cristina Anne Costello Unsplash.

Living by the sea, I am accustomed to seeing the tide rise and fall twice each day. But what causes the tides?

Gravity is the cause, anything with mass has a gravitational force.

The Moon's gravity pulls at our oceans, creating a bulge. As the Moon circles the Earth, the bulge changes position, meaning that the water level can be higher or lower at different locations all around our planet.

The highest tides (spring tides) occur when the Sun, Earth, and the Moon form a straight line. Now the gravity of the Sun and the Moon pull together, creating the highest tides. The lowest tides are called neap tides.

There is an estimated 1.35 billion cubic kilometres of water on our planet which covers just over 70% of its surface.

End of article.

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We can only imagine what our early ancestors were thinking as they gazed up at the night sky, were they curious as to what the heavens had to hide?

Now it is very different as we have developed sophisticated telescopes and other specialised scientific instruments that are helping to reveal some of the secrets the Universe holds.

Simple life forms were living on our planet over 3.5 billion years ago, since that time billions of animal species have existed, and millions of species are still alive today.

The evolutionary path for life has been long but at last, we have finally arrived. Our highly developed brain has given us intelligence and curiosity, now we can try and make sense of our existence.