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According to the European Space Agency, humanity has been in pursuit of the stars for a long time, with the history of astronomy tracing back to the Assyro-Babylonians around 1,000 BC.
Each planet in our Solar System orbits the Sun along a distinct path. Currently, Earth’s orbit is nearly circular (in terms of spatial distance) – Earth’s orbit varies by a maximum of around 2% from its average position. This relatively low variability allows life to flourish on Earth, as our planet never gets too far or too close to the Sun. The Measure of Things explains that Earth is held in this orbit due to the gravitational force exerted by the Sun’s mass.
However, other massive bodies also drift within our Solar System and influence Earth’s orbit, such as Jupiter and Saturn – the two largest planets in the Milky Way galaxy, weighing 318 and 95 times that of Earth, respectively. As per Space, these colossal planets have played a crucial role in establishing the proper positions of inner planets within the Solar System and shielding them from collisions with asteroids and other massive objects in space.
Solar System’s Vacuum Cleaners As scientists lack direct observations from the early Milky Way era, they often turn to evidence from other planetary systems to uncover secrets about our own history.
One revelation is that giant planets like Jupiter can attract smaller celestial bodies as they move towards the Sun’s center. This phenomenon has earned them the moniker “Solar System’s vacuum cleaners,” as they sweep up other planets or encountered small celestial bodies.
Jupiter, though the largest planet, isn’t the sole guardian of Earth within our solar system. In a study aimed at illustrating how Earth and other planets would fare without the two largest planets, a NASA researcher simulated scenarios using what’s known about these planets’ impacts.
What they discovered was that without Saturn, our planet would experience more collisions with asteroids, much like if Jupiter was absent. The gravitational force of these giant planets is believed to prevent floating objects within the asteroid belt from colliding with Earth and other inner planets, as well as to prevent these small bodies from conglomerating into another planet. Jupiter can also fling small objects out of the Solar System, throwing them into alternative orbits, according to NASA.
Planetary Impacts Researchers are only beginning to explore the ways in which the presence of other planets affects life on Earth. By studying climate models from Earth’s history, scientists published a study in the Proceedings of the National Academy of Sciences revealing more about Saturn’s influence on life on our planet.
They found evidence in Earth’s sedimentary cores of cycles of drying and refilling of water bodies throughout its history. They then correlated this with changes in Earth’s magnetic field, indicating variations in its orbit. Due to its massive size, Saturn’s gravitational pull is known to influence Earth’s orbit, but what this study unveiled is something novel – Saturn’s ability to shift Earth’s orbit every 405,000 years. This process, which has been ongoing since the time of dinosaurs, has led to more extreme seasons on Earth, with patterns found in Earth’s core samples used in the study.
In another simulation study by researchers at the University of Vienna, scientists discovered that without Mars, our planet’s orbital path would deviate from relative regularity – Earth’s orbit would move closer to the Sun by about 10%. According to New Scientist, this distance might still allow the origin of life, but it would certainly lead to a life vastly different from what we know today.
In fact, even a 20-degree tilt change of Mars would make Earth’s orbit shift – during part of the year, our planet would be closer to the Sun than Venus is currently. And if Mars tilted 30 degrees, Earth would be ejected from the Solar System entirely, as New Scientist suggests. At that distance, without the warmth of the Sun, life would become untenable on the blue planet.