The question of whether we’re alone in the universe is one of the questions that has frustrated mankind since we first looked to the skies and wondered what is out there. While our space exploration efforts have been relatively limited to date, what are the chances of us finding life on other planets?
How Many Habitable Planets Are There
We can start to get an idea of the massive size of the universe when we consider that the latest estimates suggest there may be 20 sextillion planets out there. This figure is based on numerous assumptions, so it’s unclear how accurate it could turn out to be.
The next point to consider is how many of these planets are habitable. Some sources suggest that we use 2.5% as the percentage of planets that may be suitable for life. In 2019, Penn State University researchers put the number of planets in our galaxy with the right conditions for life at up to ten billion.
It’s worth bearing in mind that scientists can’t yet be certain about what makes a planet habitable in the first place. We tended to focus in the past on Earth-like conditions with a planet orbiting a yellow dwarf star. Yet, it’s become clear that red dwarf stars and others may also allow life to flourish in the right conditions.
What Evidence Have We Found So Far
NASA has confirmed that its exoplanet program aims to discover life on other planets. However, they admit that this search could take decades, with no guarantee that we’re lucky enough to find the right planets or even that these planets exist.
We occasionally see news stories about discoveries being made on Mars or elsewhere, but for the moment none has provided the evidence needed to give a definitive answer.
Telescopes, space probes, and other methods have so far failed to produce compelling evidence that life exists on other planets. However, the search is going to continue as long as we continue to be fascinated by this subject.
Why Haven’t We Found Evidence of Life
Assuming that life exists somewhere else in the universe, shouldn’t we have found some evidence by now? Physicist Enrico Fermi coined the Fermi paradox in the 1950s. He asked that if the conditions for life springing up are as widespread as appears to be the case, then, ‘where is everybody?’
Several theories have been put forward to explain the lack of evidence found so far. Some suggest that intelligent life is too rare for us to find each other across the vast distances in the universe. Others believe that advanced civilisations have been too short-lived to create the kind of technology and far-reaching impact that would make them obvious to us.
What Does the Future Hold
As we explore more of the world around us, we likely get a clearer view of whether life on other planets is a possibility. While the idea of meeting extra-terrestrials remains tantalisingly distant, we can at least start to narrow down our search.
The Drake Equation is a mathematical formula put forward by astrophysicist Frank Drake as a way of calculating how many alien civilisations may exist in the Milky Way. This famous equation contains a huge level of uncertainty since the numbers included in it are extremely approximate.
Once further research starts to fill in some of the blanks contained in the Drake Equation, we could see more accurate estimates begin to appear. Unless we get lucky and the perfect piece of evidence falls into our hands, this can only be done by continuing to carry out research using all of the scientific knowledge and instruments known to us.