Our galaxy could have millions of Earth-like planets with life that radio dish telescopes and SETI continue to search for.
Our galaxy could have millions of Earth-like planets with life that radio dish telescopes and SETI continue to search for. Contributed

DARK SKIES: Curious astronomers sometimes left in the dark

OUT of the countless billions of galaxies in the universe, nothing is more exciting to astronomers than finding something new, such as a comet, an asteroid, a planet orbiting another star, a supernova, colliding galaxies or a whole mass of them.

So how do astronomers know if they have found a new galaxy?

They don't, as what they see as "new” has been sitting there since the beginning of time and they have just come across it by accident.

You've probably walked along a sandy beach and spotted something that stirs the imagination.

As you get closer, your heartbeat races - it has a shape! Your curiosity kicks in. What is this? Where did it come from? What's it made of?

Upon closer inspection your senses tell you it's foreign.

It deserves a closer inspection but with what?

The same sort of contemplation applies to astronomers.

As they scan the universe, using powerful radio, ultraviolet, infra-red, visible, X-ray and gamma ray telescopes, they are always finding something new.

From ongoing research, astrophysicists can determine if the discovery is within our galaxy or from another, as the universe as we know it is infinite - with no beginning or end.

Over the past 25 years the Hubble Space Telescope has been operating, it has found and imaged colliding galaxies, strange-looking nebulae and galaxies. Some are so distant, they look like a "white sheet”.

With all our technology, it's impossible to tell how many galaxies exist.

Are they part of the universe we know?

As a noted astronomer once said, "There will come a time in the far distant future when all matter and energy that makes up a universe of uncountable stars, planets and galaxies has depleted itself.

"Nothing will remain, except a jet black void, where no light of any kind will ever been seen, ever again.”

Of all the questions asked on this planet, one sticks out the most: are we alone?

Could there be other solar systems with Earth-like planets harbouring life as we know it?

To search for those answers we turn to SETI - the Search for Extra Terrestrial Intelligence program, which was in full swing back in the 1980s.

Although it did not pick up any telltale sounds of life beyond the solar system, it continued to operate 24/7.

But due to ongoing costs and no results, SETI was wound back.

But what if SETI did pick up a signal from within our galaxy?

Would we have the means to interpret a message?

Probably not, as the type of signal received could be in a code unlike what computer programmers use today.

From the very first radio transmission by Marconi in 1923, to TV, radio and mobile phones, everything is being transmitted from this planet out into space.

Who knows? One day, after earth's inhabitants have made total peace with each other, a radio telescope dish may receive a message we can interpret: "Planet Earth, do you copy?”