The search for life includes the most advanced observation machines that are known in humanity. They peer about the light years, looking for any evidence of evidence-that there is other life, beyond. What if, despite all our efforts, those observations do not provide proof of life elsewhere in our Milky Way system?
That is a scary question. What if we continue to build more and more sensitive telescopes to examine explanations of temperature and still not to find anything, asks Universetoday.com.
How many planets do we have to study to reach the conclusion, there is no one but we in the cosmos? At present, astronomers only have a small fraction of worlds, about 7,000 at the last count. A team of researchers led by Dr. Daniel Agerhausen from ETH Zurich and the Seti Institute considered what we could learn about the possibilities of living in the universe as future searches appear as empty as the current do.
They have tackled those questions via a Bayesian analysis to record constantly changing information to calculate and update probably in the number of exoplanets that could have life.
In their work, the team members assumed that the number of planets observed would be large enough to draw strong conclusions about the prevalence of habitability and live in our galactic neighborhood. However, there are still uncertainties. Even with advanced instruments, exoplanet search assignments must carefully take into account uncertainties, strangers and prejudices (such as assumptions about certain types of worlds).
The Agerhausen team has established the minimum number of exoplanets that scientists should find out how many worlds can exist with life. If scientists were to investigate 40 to 80 exoplanets and ultimately do not detect any life on one of them, this would imply that less than 10 to 20 percent of the comparable planets are home to life.
Extrapolate over the Melkweg, and you will discover that only about 10 billion of his worlds can be inhabited planets. For our part of the Melkweg it can indeed be a very small number.
Challenges in exploring distant worlds
Studying planets around other stars is not an easy task. First you have to “suck” them from the bright light of their stars. Once you have found them, you have to make some assumptions about their makeup.
Are they rocky with atmospheres (such as the earth)? Are they gas giants? Lava Worlds? Ice Giants? How close are they with their star? Do they have moons? If they have a living environment, what kind of life? And so forth.
Every type of world determines whether or not life can exist there. Moreover, each observation has its limitations, and that is reflected in the data. For example, observations can miss certain atmospheric clues that indicate their life (or the non-existence).
Scientists can completely skip certain planets and reject them as uninhabitable when they may be perfect for life. Or they can completely miss a number of planets due to observational limitations. The uncertainties are discouraging.
“It’s not just how many planets we perceive – it’s about asking the right questions and how sure we can be in seeing or not seeing what we are looking for,” said Angerhausen. “If we are not careful and be recovered in our possibilities to identify life, even a major investigation can lead to misleading results.”
Gain a lot of uncertainty from the search for life
Future searches for life on other worlds are on the drawings. Their success depends on scientists who make the right assumptions about where life can (and cannot) exist.
These assumptions – based on prior knowledge and continuous observations – should reduce many uncertainties about habitable worlds. For example, the large interferometer for exoplanets (life) was led by Eth Zurich and suggested for the launch in the following decade or so.
It is designed to look for life on exoplanets and at the same time catalog the diversity of worlds as part of his observations. To do that, the instruments on board measure the atmospheric composition of moderate terrestrial planets in the Melkweg.
The spectrometer studies the atmospheric gases for traces of relevant molecules. Think in this way: if such a probe would study the atmosphere of the earth, oxygen molecules and gases such as methane and other hydrocarbons would detect as indicative of life.
To prevent zero results, the searches of life depend on the Bayesian statistics that Angerhausen and colleagues have done. In essence, it will study the atmospheres of dozens and dozens of worlds that are comparable to the earth in mass, jet and temperature.
The aim is to find the signatures of water, hydrocarbons related to life and other biosa signatures. The results must “strengthen” the number of exoplanets studied to give a more statistical accurate accounting of planets that could (or do) life. In particular, the science teams want to see how much there are in our neck of the galactic neighborhood.
We will always have some uncertainty
Ultimately, the observations of life (and other surveys) will help answer a whole new series of questions about life -bearing worlds. How many planets have life? Which fraction of them are rocky worlds and what percentage thereof is in habitable zones?
Of those, which have clear signatures of water vapor, oxygen and methane in their atmospheres? The work that the Agerhausen team does to calculate statistical opportunities will help the life mission (and other similar missions) the right research questions when it comes to the search for habitable worlds. If the result is a single positive detection, according to Angerhausen, then uncertainties become reality.
“Even if we don’t find life,” he be on it, “we can quantify how rare – or ordinary – planets with detectable biosa signatures can be real.”
Even if future surveys such as life do not find evidence of life on neighboring exoplanets, they will still open a window to understand how rare or common habitable places are in the universe.
By considering carefully uncertainties and asking precise questions, scientists can create powerful tools to understand our place in the cosmos. Ultimately, exoplanetary science is not only about finding answers to questions about habitability and the existence of life. It is also about asking the right questions and embracing uncertainty as part of the trip.
