Searching for life in the Universe.
The likelihood of finding life in the universe other than here on earth is high, and may happen in the near future. We are searching the skies, looking for extrasolar planets around stars similar to our sun, that contain planets in regions likely to be home for oxygen breathing life. Our observatories are getting more powerful, our techniques and computing speeds for data analysis are making huge leaps, so it just depends on the timing being right for us to find a species we can talk to.
For a while now people could refer to what is known as the Drake equation as a means to wrap our minds around the statistical possibilities of finding life that is capable of replying to our calls for a face to face conversation. Such an equation helps us understand finding life is not just dependent upon if it ever existed, but instead if that species ever developed the technology capable of communication, and if they are still around to talk.
N = R* fp ne fl fi fc L
Our searches are getting more specific, finding biologically produced oxygen in the atmosphere of an extrasolar planet may sound like a daunting task, but this would really nail things down. Our home is a complex ecosystem; our bodies evolution was shaped by the environment. Our sun is a good stable size, our planet formed in a region not to cold or too warm for life as we know it. The human body relies on a fresh supply oxygen from our atmosphere, and iron to assist with the internal transportation of oxygen to our cells.
This is where the timing is key, for the universe is billions of years old, the relative abundance of iron changed over time. Stars are the big factories of the universe, fusing elements changing the distribution of material available for the next generation star systems. Fusion produces energy efficiently up to the point of iron on the periodic table, this means through the years the amount of iron and other metals in the universe has increased because of stellar fusion. Metals bond well with oxygen, iron is the most abundant metal in the universe, so as the universe aged the amount of elements capable of transporting oxygen inside living organisms increased.
Astrobiologists are working on understanding the possible biomarkers to help narrow down our search for extraterrestrial life. The first discoveries may be very simple life forms, not very much chance of a two-way intellectual conversation. But, on the other hand, due to the constant work from stellar engines producing the right combinations of elements timing may be on our side to find intelligent life similar to us.