Science Time!
Mercury
Mercury - messenger to the heavens & all those who inhabit it, a small body which boldly faces the sun, the first planet to note whenever one seeks to relay about the solar system.
With its surface covered in pale scars from raw impacts & a smattering of cliffs, Mercury is often compared to the Moon by appearance alone. It doesn't help when both objects are, in a sense, tidally locked to the things they orbit. However, in Mercury's case, the combined efforts of its highly eccentric or oval-shaped path & slow rotation make it so one day is over two Mercurian years. Also thanks to the orbit, the small body is within Earth's proximity for longer than Venus can be per orbit.
Throughout these long days, Mercury's rocky surface is heated to 427 C by the sun's unrelenting rays. Though, the planet's lack of an atmosphere allows nighttime temperatures to fall to -173 C. Only a faint exosphere exists to contain potassium, sodium, oxygen & a few other chemicals - an invisible, rough reflection of the surface's makeup.
Said surface, alongside Mercury's mantle, is proportionally thin for a terrestrial planet. Thus, its iron & nickel core takes up 85% of the planet's radius. In fact, after billions of years since its creation, it is still molten & responsible for generating a magnetic field weaker than Earth's but twenty times stronger than Venus'. It's enough to keep the ionizing solar wind at bay.
Whenever you wish to see Mercury amongst Earth's shifting skies, it never strays far from the sun. Often does it hide amongst the blinding rays of golden light throughout its quick orbit. Be sure to catch it if you could.
Venus
Traveling through the Earthly sky, Venus had been known by many across different cultures, continents & more. In fact, it was once recognized as two separate objects - the Morning Star & the Evening Star. However, a different name would ultimately stick, one for a goddess of love & beauty but still contributing to a different sort of duality.
Venus shares similar densities, masses, iron cores & sizes to its oceanic kin. It also has a geologically active surface & interior, all with mountains, valleys, volcanoes & proportionally few impact craters. However, any Earth-born organism would perish in seconds upon the second planet from the Sun.
Enveloping the world was the thick, highly pressurized atmosphere primarily composed of carbon dioxide & sulfur dioxide - two kinds of greenhouse gases. The latter was responsible for making the planet look so reflective & causing sulfuric acid rain to develop. Down on the surface, it would get so hot that bismuth & lead sulfides wouldn't be able to condense beyond mountaintops, creating a frost-like appearance. Furthermore, despite the planet technically being geologically active, its iron core was unable to maintain a strong magnetic field, exposing the atmosphere to the ionizing wrath of the solar wind.
Like Mercury, Venus possessed an odd pattern of its orbit & rotational period. In this case, a day on Venus would last for about 116 Earth days because of its incredibly slow rotation - one of only two planets to go backwards. Additionally, the planet was known to have a quasi-moon called Zoove - a tiny asteroid-like world thought to have been pushed into its path by the gravity of the nearby Earth about seven-thousand years ago.
Throughout its 4.5 billion years of existence, Venus had been a world of duality within the general vicinity of the Earth & Sun. It was named after a figure of carnal love but would have no second thought in snuffing out said love's offspring. It appeared as two seemingly separate lights from the view of the Earth. Lastly, many pages would be warranted to describe its differences from our home. Though, maybe future ponderings would shed light on what they share.
Earth
The Earth - a world unmatched in geological vigor, atmospheric variability & miraculous recovery. Outsiders may have called it a pale blue dot, one light of many orbiting a golden star, maybe something unremarkable compared to its sibling planets. We, for thousands of years and counting, have called it home.
With it being the most massive terrestrial planet & the densest planet of all, Earth represented an important force in the inner solar system. It was the one to keep its own dust ring in check, while influencing Zoove to occasionally accompany Venus, if one were to exclude the Moon altogether.
The orbital & rotational patterns of Earth were often the first things to be studied inhabiting cultures in one way or another as its path seemingly changed the positions of many objects in the sky. A twenty-four-hour day was nothing new, the rotational period was only six minutes shorter. Orbital patterns had to make up the difference, consistently keeping the planet exactly one AU, or astronomical unit, away from the burning Sun.
While the Earth shares similar masses & sizes with Venus, its geology had set itself apart from the latter largely for one thing - a convecting iron core blanketed by the insulating mantle. This allowed plate tectonics to develop & regulate heat flow through the surface. It also created a potent magnetic field - stronger even than the one surrounding Saturn. Earth had an easier time protecting itself from the solar wind than a much more massive gas giant. In fact, it was structured like that of Jupiter's, armored with radiation belts.
Right at the surface laid unprecedented variations in climate from frozen tundras to wet jungles. Oceans of water kept temperatures & geological activity in check here while creating complex weather patterns. A chemically diverse atmosphere contributed varieties in surface geology. These factors, alongside more, led to the development of a complex, persistent biosphere lasting for billions of years.
For many people alive to this day, it would be easy to become numb to what the Earth possesses, take it for granted or perhaps see it as something expendable. They'd neglect the fact they have & will always be a part of the planet. Regardless of what they or others could've thought, Earth survived things from ecological collapse to planetary collisions & still had enough in it to continue maintaining these qualities. For better or for worse, it lives.
Mars
In war, there was often something lost for the sake of someone's perceived victory. Lives were snuffed out, items & buildings beloved by communities were destroyed, & any uninvolved wildlife weren't treated much differently. Blood that would later be absorbed into the Earth's soil was like the hue that made Mars so distinct in the sky above.
Mars - the last planet of the inner solar system & the least dense of its rocky neighbors was carved out by both meteoroid impacts & geologic processes that dissipated long ago. Its familiar color came from the abundant rust upon its surface, which also boasted features like Valles Marineris - the largest canyon system in the solar system & Olympus Mons - the largest volcano of all. Marsquakes would resonate deep into so-called seismic highways, while polar icecaps would hold frozen saltwater & carbon dioxide in place.
With a thin atmosphere of mostly carbon dioxide, Mars maintained a weather system a bit similar to what would be found in the western United States. Dust devils & dust storms rampaged upon the land & occasionally engulf the planet for months uninterrupted. Carbon dioxide snowed down during the winter & rose back up as geysers. The mantle & core below all of this were frozen over ages ago, stopping the planet from keeping a magnetic field beyond highly magnetized regions in its southern hemisphere.
Mars had been compared to Earth many times in the past, considering the presence of ice caps as well as the similar rotation periods & axes. However, much like what happened with Venus, the red planet had struck down any hopes of it being a habitable world when under detailed scrutiny, just like how the solar wind struck down at its unprotected atmosphere & any oceans it could've held when it was young.
Jupiter
Beyond what the Sun offered, nothing in the solar system displayed size, raw power & influence quite like the planet Jupiter. Not even the nightly sky could’ve easily masked the planet, silently calling the attention of many cultures & leading to the development of the cyclical zodiac. If it were a mighty king, then the stars were its celestial army.
Jupiter – the largest gas giant, a body of mostly hydrogen & helium with splash of other chemicals such as ammonium. Its hydrogen contributed to a thick mantle-like layer of liquid metallic hydrogen, providing immense electrical conductivity & the right conditions to produce a powerful magnetic field. This field was so intense that it generated its own radiation, making it a consistent problem for any spacecraft daring to tread near, especially when its tail-end reached all the way to Saturn’s orbit. Overwhelming storm activity wasn’t foreign to the planet either as cyclones & other formations created the belts & bands found on the gaseous surface. However, like a persistent, ancient scar, the Great Red Spot was easily spotted upon Jupiter’s face. Even if it seemed to shrink over centuries, it remained as a bloodied tempest bigger than the Earth itself.
Additionally, Jupiter’s gravitational was nothing to sneeze at. It was so massive that the barycenter between itself & the Sun, an object it shared a similar chemical composition to, was outside of the latter, indicating how they just barely orbited each other. This same force kept the asteroid belt from coalescing into a singular body, often throwing objects toward the Sun, away from the solar system, or toward itself to consume. In a sense, the planet acted as a great instigator & protector of its rocky siblings such as Earth. If only those two knew how similar they were to each other, for better or for worse.
