Over the centuries, science has become increasingly successful in explaining the mysteries of the cosmos. We now know that the universe was created 13.7 billion years ago in a Big Bang and that it has been expanding ever since. Physicists have convincing theories and empirical evidence about how galaxies, stars and planets formed and why they behave as they do. The presence of life on Earth can be explained by Darwin’s theory of evolution by natural selection. However, there are still some things that are baffling and seem to defy understanding.Here are three of the most inexplicable mysteries.

1 –   Where Is Everyone?

As far as we know, life only exists on Earth. No evidence has ever been found that it might occur anywhere else – either within our Solar System or in the further reaches of the galaxy. But the famous Drake Equation predicts that the Milky Way should be teeming with life. This equation takes a number of variables and applies some very conservative estimates as to the number of stars with planets, how many of those planets can sustain life and then how many intelligent species might arise on them. The result is that there should be thousands of other civilisations in our galaxy. So where are they?

2  –  What Came Before the Big Bang?

To many scientists, this is a meaningless question. Since time and space were created by the Big Bang, it makes no sense to ask what came before, as there was no before. But the question refuses to go away and some physicists now accept that it is reasonable to ask it. They postulate that our universe may have been created by another one located in a different dimension. Another explanation is that it is in a never-ending cycle of expansion and contraction and has existed for ever and will never come to an end.

3 –   Observer Effect

The observer effect is perhaps the most mysterious and also downright odd question faced by scientists. In quantum physics, the very act of observing something can have an effect on it. The classic example is the famous double-slit experiment, in which electrons are fired through one or two slits at a sensor. The pattern that they form will depend entirely on whether or not they are being observed. The very act of observation seems to cause them to behave in different ways. Although now incorporated into theories of quantum physics, exactly why and how this occurs is still a mystery.
This has been a guest post by blogger Jack Rasmussen.
Jack
has studied the solar system and its 8 planets since an early age and in 2012 he developed the astronomy website planets.org.uk. Follow the latest developments and discoveries in space science on the website’s frequently updated Facebook page.