The Universe is a big, cold, dark and lonely place; and it just so happens that on Earth, we have the perfect conditions to support organisms that have gotten more and more complex over time. One of the most unanswered questions in Science, and even in general, is could there be any sort of life elsewhere in the Universe?
How big is the Universe?
We know its big. By that, we mean really big. Let’s come up with an analogy to help visualise what ‘really big’ actually means.
Picturing the size of the Universe
Imagine you have a penny on a table in front of you – now, scale the Sun down such that it is the same size as the penny. The closest star to the Sun is known as Alpha Centauri. To get to it, you must travel 350 miles from this penny, which is roughly the same distance from London to Germany. At this scale, you can see how far everything is from each other in Space; especially considering you can fit 100 Earths in the Sun.
By travelling 7.5 million miles away from this penny, you will have travelled the length of our Milky Way galaxy. To put this into perspective, that distance is like travelling from the Earth to the Moon… 30 times – on the penny scale. Converting 7.5 million miles back to the real scale; you get 100,000 light years.
These distances are crazy! In fact, too crazy to continue using this scale any longer. I strongly advise you to watch this video below. Soon into watching it and you’ll be hooked. This is the best representation I have seen on how big the Universe is and I promise it will make you feel tiny.
As you can see, there are billions and billions of Stars in a Galaxy, and billions and billions of Galaxies in our Universe with a potential of a multiverse that possess different laws of nature as you go from Universe to Universe. If we can produce theories such as these, why have we not found life elsewhere in our Galaxy, never mind the Universe?
Finding life on other planets
On our planet, where there is water there is life. What Astronomers do, is they look for planets that orbit a Star in another Solar System under similar conditions to those on Earth. Planets in a Solar System that isn’t ours are known as Exoplanets.
How do we find exoplanets?
To literally see something, light must travel from that object into our own eyes. In astronomical terms; light must travel into the telescope from the object we are observing, in order to see it .
Since the light of a Star outside our solar system is going to ‘out-shine’ any light coming from one of the planets orbiting it, we cannot directly detect an exoplanet. Astronomers find exoplanets by studying differences in light detected from the Star it is orbiting, over a period of time. Essentially, they look for tiny moving shadows moving across this Star, that turn out to be planets. By studying these shadows further, more can be deduced about their conditions.
Do you see how difficult this process is? It is like detecting a fruit fly flying in front of a car headlight, millions of miles away, THEN, trying to find the fly’s colour.
As you can imagine, even the most powerful telescopes cannot differentiate between the Star’s and Planet’s light; meaning we cannot directly observe exoplanet surfaces.
What if we had a telescope powerful enough?
Unfortunately, having such equipment is not enough due to redshift or blueshift. Imagine you are sat waiting for the bus, and the sirens of a police car from up the road is driving towards you. You may have noticed that as it approaches, the pitch of the sirens get higher, and as the car drives away from you, the pitch lowers, if not, time keep an ear out for it. This is due to the Doppler effect . The same applies with redshift and blueshift.
Since everything in the Universe is moving in different directions, we can have a mixture of two possible outcomes; if the Star we are observing is moving away from us – we get redshift. If the star is moving towards us we get blueshift. Redshift is when the wavelengths of light are ‘stretched’ and so become more red. Blueshift is when the wavelengths of light are ‘squashed’ so become bluer, as shorter wavelengths correspond to bluer light.
Can you see how Star systems moving in different directions at high speeds, a long way away, may affect our results? All we would see in this ‘perfect telescope’ is a red or blue smudge!
So how do we know anything about exoplanets?
We have our incredible technology to thank for this. Once Astronomers find a moving little shadow across a Star in another Solar System; provided they are sure it is an exoplanet, they begin by studying the Star this new found planet is orbiting .
If the distance between the planet and Star are suitable relative to the calculated temperature on this planet (estimations of Star temperatures can be made by simply knowing how big it is), simulations can be made on a highly specialised, highly powerful computer, of this exoplanet’s atmosphere. By using these simulations, we can further work out if this atmosphere allows for water to be present. If water is present, we can assume that the planet may be habitable!
In conclusion, we are far from finding any sort of life on other planets. What do I think? I think there very well may be life elsewhere, considering how small we are in comparison to our Galaxy, mind you our Universe! I mean, have you seen that video above?
Let’s hope intelligent life forms out there are on the same quest as us. Some day, we could bump into them!
If you have any questions, leave them below and until next time, take care.
Please note; no copyright infringement is intended. All images used have been labelled for re-use on Google Images. If any artist or designer has any issues with any of the content used in this article, please don’t hesitate to contact me to correct the issue.
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