To answer this question, astronomers have been using a variety of methods in the past decades to search for habitable planets and for the signals from extraterrestrial observers. If they discovered Earth as an exoplanet, and were close enough to study the planet further, they would easily see that our atmosphere has been altered by the presence of intelligent, technologically advanced life.
Advertisement
One good thing about this technique is it lessens the area of research, limiting the period of study completion to less than a human life span.
When a planet passes in front of its host star, it causes a small transient dimming of the star.
Search for extraterrestrial life (or SETI) projects have been conducted since the 1960s, but researchers are now planning a new, massive, strategic SETI project called the Breakthrough Initiative. They determined that there are around 10,000 stars where we should be looking transits.
The light from distant stars blots out the comparable faint light from exoplanets, so there are two main ways astronomers infer the presence of these planets.
Astronomers are narrowing down the planets that researchers should look at when searching for life on other planets.
The indomitable Kepler space telescope’s search for exoplanets looks for tiny fluctuations in light as planets transit their suns, and that means we only see planets if they pass between their sun and us – in other words, the orbital plane of the planet has to be oriented just right.
Currently, astronomers are using a variety of methods to look for habitable planets and for signals from extraterrestrial beings.
Maybe a team effort is the best way to search for aliens.
In the next five or so years, the European Space Agency’s Gaia satellite is likely to discover most of the nearby stars in the Earth transit zone, Heller says.
100,000 still sounds like a lot of targets, but it’s way less daunting when you consider the 100 billion stars in the Milky Way galaxy – and it happens to be about the volume of space we can see with today’s radio telescopes. The heavier a star, the shorter it lives, providing less time for intelligence to evolve.
“It’s impossible to predict whether extraterrestrials use the same observational techniques as we do”, said Heller in a prepared statement. These worlds are the proverbial “Holy Grail” as they could be worlds with Earth-like qualities.
Hunting alien life has been one of the most exciting yet elusive endeavors of mankind.
Now, Ralph Pudritz from McMaster University in Canada, together with René Heller from the Max Planck Institute for Solar System Research in Germany, have focused their attention back on Earth by presuming that extraterrestrial observers, also adopting the transit method, may have already detected the Earth.
Advertisement
According to the duo, large-scale projects that hope to pick up a signal from an exoworld – such as the Breakthrough Listen initiative – should focus on the Earth’s “transit zone”. Instead of trying to identify alien life, we should ask ourselves: What happens if alien observers locate planet Earth while it transits the Sun?
