Now is a great time to be alive; for those who have always gazed up at the stars glimmering in the night sky, and asked that eternal question, "Are we alone?" We've come a long way from 1961; when Frank Drake devised his iconic equation, which was meant to estimate the number of alien civilizations in our galaxy. His attempt was to approximate an answer to a question that, at the time, seemed unanswerable.
But things are changing. Just decades ago, planets, especially Earth-sized ones, were thought of as quite rare. Today we know that they outnumber the amount of stars themselves! We also know that planets in the so-called ‘habitable’ zones of stars (where conditions would be just right for life to form) are common.
Planet hunters search for these extra-solar planets, called "exoplanets" for short, and they are often finding new and more fascinating worlds. Scientists can find these planets using a variety of techniques. Measuring luminosity output from stars and watching where it dips at regular intervals, measuring a stars wobble away from the centre of gravity and, in rare cases, even directly observing the planets.
Most astronomical news sites now have whole sections dedicated to exoplanets and the search for alien life. In 2014, NASA scientists announced that they expect signs of life to be found within the next 20 years. They even say that this estimate is conservative and that they predict up to 100 million worlds inhabited by extraterrestrial life. So, how exactly do scientists expect to achieve such a goal?
For years SETI, (the Search for Extraterrestrial Intelligence), has been collecting and sifting through mounds of data. You can even participate in the www.setiathome.ssl.berkeley.edu/ program by letting your computer analyse some of the data on its own when you're not using it. However, search efforts have also been ramping up as of late. In July 2015, famed astrophysicist Stephen Hawking and Russian billionaire Yuri Milner announced a new $100 million initiative called Breakthrough Listen. Billed as the most powerful, intense, and comprehensive search for life undertaken in all of human history. These extraordinary listening devices will scour the skies like never before, in search of the tiniest signal - that perhaps we're not alone!
The first sign of life might not even come from elsewhere in the void. Having found signs that there was once water on Mars, scientists are now searching for similar clues to see if life - even the most fundamental microbial forms - once walked the surface of the red planet. Jupiter's moon Europa and Saturn's moon Enceladus, both known to contain liquid seas under their icy surfaces, are also prime candidates for the search for life right here in our solar system.
Regardless, progress in just the past decade, have been remarkable. Astronomers have successfully detected water and auroras on exoplanets, characterized the chemical composition of their atmospheres, and even determined some of the weather on these faraway worlds. It's only a matter of time before they find signs of life, and if they do, there's a good chance we'll be here to witness it.
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