The Milky Way galaxy is estimated to be about 100,000 light-years across and is 12 billion years old. In comparison, the observable universe is 93 billion light-years across and 13.8 billion years old. Suffice it to say, our galaxy and universe are vast. So, why would there only be one planet like ours? Researchers think there are billions of planets like the blue marble of the cosmos.
More Neighbors Than We Thought
The scientific consensus is that there are many Earth-like planets in the galaxy, but the debate is the number. The size of space raises the odds of at least one other planet that harbors life. But what if you were told there were six billion exoplanets similar to Earth in size and terrain?
According to a new study published in The Astronomical Journal, there could be as many as six billion Earth-like planets in just the Milky Way galaxy. Researchers at the University of British Columbia believe there could be one exoplanet for every five Sun-like stars in our galaxy. With an estimated 400 billion stars in the Milky Way, we might be looking at several billion exoplanets (rocky, comparable to Earth’s size, and orbiting a G-type star).
Study authors used information from NASA’s Kepler data mission to determine the number of exoplanets in a goldilocks zone (a region of a star that produces a habitable surface temperature to host liquid water). The team then used a tactic called “forward modeling,” in which you use your model to predict what you would observe and then compare these predictions to your data. Finally, scientists simulated all the exoplanets around stars and labeled individual planets as either “detected” or “missed” based on their size and distance.
Michelle Kunimoto, University of British Columbia (UBC) researcher and the study’s lead author, explained that the purpose of this study is to understand planet formations and evolution theories better and help put together future missions.
This is not the first time UBC has been involved in a similar headline-making story. In March, a UBC student found 17 new exoplanets, including one that is about the same size as ours. It is called KIC-7340288 b and has Earth-like attributes: small enough to be rocky, roughly 1.5 times the size of Earth, and is in the habitable zone.
2020: The Year of Exoplanets
It has been a fruitful year in the hunt for exoplanets. Scientists – professional and armchair – have presented findings that can better help us locate Earth-like planets or improve our understanding of our cosmic neighbors.
One study looked at the nature of the exoplanets in our galaxy, and it concluded that we might be living in a so-called Ocean Galaxy. It is now thought that about 4,000 known exoplanets could be water worlds. Another study suggested that airborne dust on exoplanets could inform us of the presence of alien life. New estimates indicate that about one-fifth of Sun-like stars could have a planet comparable to Earth in its orbit.
Space exploration is booming thanks to a wave of new technologies and a treasure trove of data.
“Know Where to Look”
With all this new information, teams of researchers now “know where to look” in their hunt for alien life. Mineral dust, active volcanoes, and hydrogen atmospheres – there are all kinds of things that experts are looking for in their quest. Considering the immense number of planetary neighbors, it could only be a matter of time before we learn of other lifeforms.