While NASA’s New Horizons flies by Pluto and targets new destinations farther than we can imagine, examining our relationship with the Sun could help explain why the Earth can sustain life. What if Earth moved a mile closer to the Sun? Would we all burn up? Would our atmosphere disintegrate? Would we have an extreme runaway greenhouse effect and dry up like Venus? The concept of a habitable zone, sometimes referred to as the “Goldilocks Zone,” is vital in order to explain the possibilities.
WOULD MOVING EARTH CLOSER HAVE A BIG EFFECT?
Since the Earth’s orbit is an ellipse, not a circle, its distance from the sun varies from a minimum of 147.1 million kilometers each January to a maximum of about 152.1 million kilometers each July. The range of this distance has little effect on Earth’s weather with the Northern Hemisphere’s summer occurring during the time that Earth is farthest from the Sun and winter occurring when Earth is closest to the Sun.
THE ANSWER COULD LIE IN THE HABITABLE ZONE
The habitable zone is the region around a star where the average temperature on a planet allows for liquid water, according to Universe Today. However, the concept is based off of the Earth and focused around the range at which worlds similar to Earth could exist. While we are lucky at the moment to lie within the sun’s habitable zone, future generations might not be so lucky. Since stars go through growth and decay as humans do, our sun will continue to grow warmer until our oceans boil away.
THE GOLDILOCKS ZONE ISN’T THE ONLY ANSWER
Although the habitable zone seems like an easy answer to explain why life on Earth is able to sustain itself, the goldilocks zone isn’t the only requirement for life; it also depends on the type of star in a solar system. The moon, for example, is an obvious example of this; it remains our companion without a chance for living life.
Scientists continue to search for the probability of life on Europa and Enceladus, way outside of the sun’s habitable zone. We are lucky to have our Sun because it’s neither too big to harm us with deadly solar flares nor too dim, like red dwarfs, which cannot provide us with the warmth we need.
Gaining insight on what makes Earth different from its neighboring planets could help us understand the likelihood of finding Earth-like worlds in orbit around other stars. According to the 3rd edition of Life in the Universe by Jeffrey Bennett and Seth Shostak, other stars also have their own habitable zones, meaning distances at which a world similar in size to Earth, and with a similar atmosphere, would be habitable. The sizes of these habitable zones, however, are different for varying type of stars.
