An unprecedented wave of optimism spreads across the astronomical community regarding the prospects of finding an Earth-like planet. This opinion is based on recent advances in exoplanet detection which skyrocketed in the last 5 years. Decades ago, the common conception in astronomy stated that our solar system would be an exception in the infinite space – no planets orbiting other stars were identified. Although quite a few attempts were made to prove the existence of exoplanets (planets orbiting around other stars) throughout the 19th and 20th centuries, only the final decade of the latter (backed by instruments powerful and sensitive enough to gather reliable data) allowed the confirmation of the existence of extrasolar planetary systems.
Today, the most common belief is that at least tens of billions of planets inhabit our galaxy alone. Astonishing results were recently gathered, after the Planet Hunting Kepler Space Telescope was launched in 2009. Since then, 1739 planets are confirmed in the NASA databases (this month). Highly sensitive monitoring technology is available to identify the small light variations of a star, when one of its planets passes in front of it as viewed from Earth (the Transit method, used on Kepler spacecraft), or the small “wobbling” of the star due to the planet’s gravity moving around it (radial velocity measurement), to name two of the most successful detection methods principles.
Despite these spectacular technological breakthroughs, moderation should be the rule in present-day results. One of the most famous planetary systems, belonging to star Gliese 581, in 2010 was widely considered to host several planets, including one candidate for the Goldilocks zone (the distance from the sun that allows the existence of liquid water, and therefore considered to be highly suitable for life development, as we know it). This planet, called Gliese 581g, and being one of the favorite candidates to the Earth-like planet selective group, was recently discovered to be a false positive, along with one of its neighbor, Gliese 581d. Thus, the 2014 study reduced the initially 5 planet list of this star to only 3.
[ads2]
Future measurements will provide new data, some opinions claiming that this planetary system has in fact up to 6 members strongly suggesting that nothing is certain in current planet hunting yet. On the other hand, the giant leap from pure speculations years ago to the present indisputable fact of existence of exoplanets, regardless how may revolve around a sun is overwhelming enough and opens up a new perspective of our place in the universe.