According to a new paper proposed by astronomer Rory Barnes of the University of Washington, Earth may seem inhabitable if observed from hundreds of light years away say
Everyone is always excited when we search and find new alien exoplanets, and even more if they are located in the habitable zone of their star. But… until now, no one has asked how Earth might look like to other Alien civilizations that are looking for the same thing as we are… Alien life. We know that Earth is inhabited because, well… we live here, but it might not look so for other Alien civilizations searching the cosmos for life. According to astronomer Rory Barnes of the University of Washington-based Virtual Planetary Laboratory, there are numerous questions we should be asking ourselves, and one of them is how Earth would look like to other civilizations searching through our solar system.
Barnes and his team are creating what is called a “habitability index for transiting planets” which will be used as a guide to give ranks to exoplanets in order to help prioritize the search for life.
Astronomers hunt for exoplanets in the cosmos not through direct observations (because that would be nearly impossible with our technology today) but through the attenuation of light that occurs when a celestial object passes in front of its star, something astronomers refer to as “transit”.
Whether an ‘Alien world’ is potentially habitable or not is something decided by numerous factors including the amount of energy the planet receives from its star, the distance and the radius of the orbital path of the same and the behavior of its neighboring planets. But not only are these factors important, astronomers must also know the size of the planet. In order to do so, they use spectrometry in order to estimate the mass and radius of the host star, from which astronomer can then estimate the size of the planet that passed in front of the star.
They use this data to create a model of a planet — “an idea of a planet,” Barnes said, which is then compared with information about other worlds. “And you basically try and sort out, do I think that could reasonably be a planet that’s habitable?”
Regrettably, validation and confirmation are something time-consuming and expensive for astronomers. This is why the habitability index, proposed by Barnes, could help astronomers rank and prioritize planets which in turn could help them determine whether or not they should take a closer look at it.
According to these calculations and the habitability index, Earth, if observed from afar as we now observe other exoplanets in the cosmos, has about 82 percent of being habitable.
But should Earth have 100%? Well not exactly.
“Basically, where we lose some of the probability or chance for life, is that we could be too close to the star,” Barnes said. “We actually are kind of close to the inner edge of the habitable zone. If we spotted Earth with our current techniques, we would reasonably conclude that it could be too hot for life.”
The habitable zone is considered by astronomers as the swath of space around a star where an orbiting planet could keep liquid water on its surface, something that greatly increases the probability of developing life as we know it. Of course, the entire idea of looking for life as we know it might be a mistake, because life elsewhere could have developed under totally opposite conditions, meaning that somewhere out there maybe life does not need water or oxygen. That, however, is another subject.
Returning to the habitability index, proposed by Barnes and his colleague, we note that the distance to the host star is only one of the numerous other factors Barnes and his team account for with the habitability index. Among other factors, Barnes and his colleagues included the composition of the planet, details of its orbital path and the behavior of neighbouring planets.
Barnes and his colleagues argue that „we have to think about the Earth as if we don’t know anything about it,” “We don’t know that it’s got oceans, and whales and thing like that — imagine it’s just this thing that dims some of the light from a nearby star when it passes,” added Barnes.
It becomes a sort of sociology question, Barnes said. People would get pretty excited if astronomers did spot an exact Earth twin orbiting an exact Sun twin out there, Barnes allowed.
Understand the factors proposed by Barnes and his team, we note that while the paper certainly tries to make life easier for astronomers and scientists around the globe, it could also cause them to miss potentially habitable planets due to a lower index rating. Earth is the best example with only 82 percent according to the habitability index. Even though Earth is teeming with life, scientific calculations could indicate otherwise, causing astronomers to point to planets with a higher habitability index, something that could result in a obvious mistake.