Humanity may not be extraordinary but rather the natural evolutionary outcome for our planet and likely for others, according to a new model for how intelligent life developed on Planet Earth.

The model upends the decades-old "hard steps" theory that intelligent life was an incredibly improbable event and suggests that maybe it wasn't all that hard at all. A team of researchers at Penn State, who led the work, said the new interpretation of humanity's origin increases the probability of intelligent life elsewhere in the universe.

"This is a significant shift in how we think about the history of life," said Jennifer Macalady, professor of geosciences at Penn State and co-author of the paper, which was published on Feb. 14 in the journal Science Advances.

"It suggests that the evolution of complex life may be less about luck and more about the interplay between life and its environment, opening up exciting new avenues of research in our quest to understand our origins and our place in the universe.”

First developed in 1983, the "hard steps" model argues that our evolutionary origin was highly unlikely due to the time it took for humans to evolve on Earth relative to the total lifespan of the sun—and therefore, the likelihood of human-like beings beyond Earth is extremely low.

In the new study, a team of researchers that included astrophysicists and geobiologists argued that Earth's environment was initially inhospitable to many forms of life and that key evolutionary steps only became possible when the global environment reached a "permissive" state.

For example, complex animal life requires a certain level of oxygen in the atmosphere, so the oxygenation of Earth's atmosphere through photosynthesizing microbes and bacteria was (God’s) natural evolutionary step for the planet, which created a window of opportunity for more recent life forms to develop, explained Dan Mills, postdoctoral researcher at the University of Munich and lead author of the paper.

"We're arguing that intelligent life may not require a series of lucky breaks to exist," said Mills. "Humans didn't evolve 'early' or 'late' in Earth's history, but 'on time' when the conditions were in place. Maybe other planets are able to achieve these conditions more rapidly than Earth did, while other planets might take even longer.”

In the new study, the researchers proposed that the timing of human origins can be explained by the sequential opening of "windows of habitability" over Earth's history, driven by changes in nutrient availability, sea surface temperature, ocean salinity levels, and the amount of oxygen in the atmosphere.

During medieval times, almost all Christian theologians accepted the Ptolemaic Earth-centered Greek view of the universe as an absolute universal truth of both nature and religion. The Catholic Inquisition punished those who dared to voice other ideas.

Even in America today, many Christians avoid learning about new scientific discoveries. According to a February 2015 study, Religious Understandings of Science, members of non-Christian religions—42 percent of Jews and 52 percent of Muslims, Buddhists, and Hindus (taken as a group)—are more than twice as interested in new scientific discoveries as Protestant evangelicals (22 percent). About 30 percent of all evangelicals see the worldviews of science and religion as being in opposition.

I do not know why so many Christians believe that the rarity of life in our universe proves that God must have created life only on this planet. Perhaps they believe that if intelligent life were found to exist on other planets, it would diminish the miracle of God's creation of human beings.

For me, the opposite is true. That God's universal creation is filled with life is simply the result of God's mercy and love for all living things. The Qur'an and the Hebrew Bible both teach that the Living God created the whole universe to be conducive to the universal development and evolution of life in general and intelligent life in particular.

Now, some scientists have identified a group of planets outside our solar system with the same chemical conditions that may have led to life on Earth. They found that the chances for life to develop on the surface of a rocky planet like Earth are connected to the type and strength of light given off by its host star.

They propose that stars that give off sufficient ultraviolet (UV) light could kick-start life on their orbiting planets in the same way it likely developed on Earth, where the UV light energizes a series of chemical reactions that produce the building blocks of life.

Carbon from meteorites that slammed into the young Earth interacted with nitrogen in the atmosphere to form hydrogen cyanide. The hydrogen cyanide rained to the surface, where it interacted with other elements in various ways, powered by the UV light from the sun. The chemicals produced from these interactions generated the building blocks of RNA, the close relative of DNA, which most biologists believe was the first molecule of life to carry information.

Today, very few religious people think that if the Earth revolves around the sun, it makes humans less important to God. The value, meaning, and importance of human life are not scientific issues; they are religious issues.

So too, when before the end of the next decade, astronomical evidence of stars with Earth-like planets at the right distance from their star to have liquid water and an atmosphere with oxygen is found, there will be no need for evangelical Christians to deny the evidence and condemn the scientists as anti-religious.

Religious people need to know that the Torah and the Qur'an clearly teach that the Living God created the whole universe to be conducive to the universal evolution of life.

As a Psalm of David says, “Your kingdom is a kingdom of all worlds, and Your dominion is for all generations.” (145:13). And as the Qur'an says, “We have not sent you but as a blessing for all the worlds.” (Al-Anbiya 107). Muslim commentators say this refers to the 18,000 worlds created by Allah. Our world is just one of them. (Mir'at-e-Kainat, vol. 1, p. 77).