1. Astronomy

 1. Astronomy (9/6/2022)

The Galaxy:

    The galaxy is a standard spiral galaxy, characterized by its immense size with a galactic radius of 51,384 light-years. Within this expansive region, the Galactic Habitable Zone spans from 24,150 to 30,830 light-years, offering a potential haven for life-sustaining environments.

The Sun:

    The Sun, our star, belongs to the G type main sequence category and has a mass of approximately 0.843 times that of our solar mass. It is currently 4.168 billion years old and is expected to remain in existence for another 12.524 billion years. With a diameter of roughly 1.2 million kilometers, it is equivalent to 0.872 times the radius of the Sun. In terms of brightness, the Sun is about half as bright as our own sun, as indicated by its absolute magnitude of +5.64. Its surface temperature is around 5213 Kelvin. The Sun's temperature being lower than our sun's results in a goldilocks zone, or habitable zone, extending between 0.678 and 0.976 astronomical units (AU). The frost line for water, on the other hand, is located at a distance of 3.447 AU from the Sun. The Sun is orbited by a total of six planets. The innermost orbit, known as Terra-1, is occupied by a small terrestrial mesoplanet with a mass of 0.023 times that of Earth. This planet orbits at a distance of 0.59  AU from the Sun. Moving outward, the second planet, called Home, is a terrestrial planet located at a distance of 0.89 AU from the Sun, placing it within the goldilocks zone. Home has a mass of 1.54 times that of Earth. The third terrestrial planet, named Terra-2, is found at a distance of 1.49 AU from the Sun and possesses a mass of 1.2 times that of Earth. At a distance of 2.7 AU from the Sun lies the inner limit of the asteroid belt known as the Amasa Belt. This belt houses three dwarf planets and stretches to its outer limit at 4.1 AU. Beyond the Amasa Belt, the largest planet in the solar system can be found. Known as Major-Gas, it is a gas giant located 5.18 AU from the Sun and possesses a mass of 346.8 times that of Earth. Another gas giant resides at a distance of 19.66 AU from the Sun, with a mass of 116.03 times that of Earth. Finally, the last planet in the solar system is an ice giant located 78.1 AU from the Sun, with a mass of 14.53 times that of Earth. Beyond the ice giant lies the Debris disk, spanning from 101.68 AU to 123.18 AU from the Sun, which is home to five dwarf planets.

The Stellar Neighborhood:

    The stellar neighborhood refers to a spherical region around the Sun with a radius of twelve light years. Within this region, there are a total of twenty-five star systems. The closest system, named SYSTEM Q, consists of a single K-class star located just 4.98 light years away from our Solar System. On the other hand, the farthest system, known as SYSTEM C, is situated 11.87 light years away and is a triple star system comprised of two M-class stars and one L-class star.

Home:

    Home is a terrestrial planet currently awaiting an official name, yet its significance within the solar system and this project cannot be overstated. With a mass 1.54 times that of Earth, Home boasts a radius 1.12 times that of Earth, approximately measuring 7,159 kilometers. The gravitational force experienced on this planet is approximately 22% stronger compared to Earth's gravity, while its density amounts to 6.042 grams per cubic centimeter. One notable characteristic of Home is its axial tilt of 24.6 degrees, which contributes to the occurrence of seasonal variations on the planet. With an average temperature of around 14 degrees Celsius, Home provides a relatively moderate and habitable climate. Positioned at a distance of 0.89 astronomical units (AU) from the Sun, Home completes a full rotation in a period of approximately 25.06 Earth hours.

    Home's orbit is defined by a semi-major axis of 0.89 astronomical units (AU). It follows an elliptical path with an eccentricity of 0.0153. During its closest approach to the Sun (perihelion), Home orbits at a distance of approximately 0.876 AU, while at its farthest point (aphelion), it reaches a distance of 0.904 AU. The orbital period of Home is slightly shorter than Earth's, requiring approximately 334.002 Earth days or 0.914 Earth years to complete one revolution around the Sun. In terms of Home's local days, which have a duration of 25.06 hours each, a year would consist of approximately 319.87 days.

    The composition of Home's atmosphere closely resembles that of Earth. Nitrogen (N2) constitutes approximately 73.08% of the atmosphere, while oxygen (O2) makes up around 20.95% of its composition. Notable trace elements present in the atmosphere include carbon dioxide (CO2) at a concentration of 0.02% and argon (Ar) at 0.96%. Due to Home's stronger gravitational force, the atmospheric density on the planet is approximately 1.525 times higher than that of Earth.

    The interplay between the Sun's lower mass and Home's denser atmosphere gives rise to distinctive effects on the coloration of both the vegetation and the sky. Over time, plants on Home have evolved to absorb the specific spectrum of light that maximizes photosynthesis efficiency. Given the Sun's classification as a low-mass G-class star and the additional atmospheric mass of Home, the optimal spectrum of light for photosynthesis would fall within the yellow to ocher range. The sky on Home exhibits a dimmer appearance compared to our Sun, primarily due to its lower brightness and the increased atmospheric mass.

The Moon:

    Home possesses a single satellite that closely resembles our Moon on Earth. This lunar companion of Home has a radius equivalent to 1.017 times that of the Moon and a mass approximately 1.108 times that of the Moon. Comparatively, the gravitational force exerted by the moon is only around 17% of Earth's gravity, while its density measures 3.52 grams per cubic centimeter. Home's gravitational influence sets the closest feasible distance for a moon to form at approximately 20,850 kilometers, while the farthest distance extends to roughly 1.6 million kilometers. The specific moon orbiting Home maintains an average distance of 387,873 kilometers. However, its elliptical orbit, characterized by an eccentricity of 0.05, causes variations in its proximity to Home. At its closest point (periapsis), the moon is approximately 368,500 kilometers away, while at its farthest point (apoapsis), it reaches around 407,300 kilometers. 

The moon's orbital period spans approximately 24.021 Earth days, and it is tidally locked to Home, similar to Earth's moon. This tidal locking results in the same face of the moon always facing Home, establishing a consistent orientation between the two celestial bodies.

Near Home Objects:

    A multitude of Near Home Objects (NHOs) traverse within a proximity of 0.3 astronomical units (AU) to Home's orbit, amounting to thousands of such objects. These include a diverse array of asteroids spanning sizes from mere meters to tens of kilometers in diameter. Additionally, there are various comets that approach Home, although the majority of them possess irregular orbits and lack visibility to the naked eye. However, amidst these celestial wanderers, there exists one comet that can be distinctly observed without the aid of optical instruments.

Apparent Size and Brightness:

    Firstly, let's discuss the apparent size, magnitude, and brightness of the Sun as observed from various planets in the solar system. As a result of the Sun's lower luminosity relative to our own Sun, it would appear notably dimmer. However, it is important to note that Home, being 11% closer to the Sun compared to Earth's distance from its own Sun, influences the level of brightness perceived. From Home's perspective, the Sun would appear approximately 0.5877 times as bright as our Sun.

    Now, let's explore the apparent size, magnitude, and brightness of the other planets as observed from Home. Since Home is the reference point, we will analyze how the planets in the solar system appear when viewed from Home.

Other Orbits:

    In addition to Home, there are five other planets in the solar system. These planets can be classified into two small terrestrial planets, two gas giants, and one ice giant.

Terrestrial-1:

    Terra-1 is a compact rocky mesoplanet situated at a relatively close distance from the sun, orbiting at a distance of only 0.59 AU. As depicted in the illustrations, Terra-1 is positioned in close proximity to the sun, resulting in intense heat and causing the planet to lack a substantial atmosphere. With gravity measuring at approximately 26% of that on Earth, Terra-1 experiences significantly weaker gravitational forces. Furthermore, the duration of a day on Terra-1 is nearly twice as long as that on Earth.

Terrestrial -2:

    Terra-2, a rocky planet slightly larger than Earth, maintains an orbital distance of 1.49 AU from the sun. The following tables provide detailed information regarding its physical and orbital characteristics.Terra-2 orbits the sun at a proximity similar to that of Mars, albeit slightly closer. The combination of this distance and the sun's lower temperature results in Terra-2 being significantly colder than Earth. Despite having an oxygen-rich atmosphere, the presence of such does not contribute much to the planet's warmth. However, Terra-2 does possess an atmosphere with a mass equivalent to 1.1 times that of Earth's atmosphere. Notably, Terra-2 exhibits a relatively rapid rotational period, lasting a little over 17.5 hours. Additionally, a year on Terra-2 encompasses a duration equivalent to

 two Earth years, spanning 998.9 days.

Major Gas Giant:

    This gas giant, known as M-Gas Giant, holds the distinction of being both the closest planet to the sun and the largest in size. Its prominent position in the solar system enables it to exert gravitational influence over the neighboring asteroid belt, playing a crucial role in safeguarding Home from potential impacts by asteroids and comets. M-Gas Giant follows an orbit located slightly beyond five AU from the sun and boasts an impressive retinue of more than 70 moons. A day on M-Gas Giant extends slightly over thirteen hours, while a complete orbital revolution around the sun spans 12.97 Earth years, equivalent to 8,511 days on the M-Gas Giant.

Gas Giant:

    The second gas giant in the solar system, positioned at a distance of approximately 20 AU from the sun, boasts a substantial mass equivalent to 116 times that of Earth. This gas giant hosts an extensive assortment of celestial companions, with over 100 moons adorning its orbit, accompanied by a prominent system of planetary rings. Among its diverse moon population, 11 of them are considered major moons, each possessing a mass equal to or exceeding 0.5 times that of Earth's moon. With a rotational period of 9.67 hours, the gas giant completes a full day-night cycle in a relatively short span of time. On the other hand, its orbital period around the sun extends to approximately 95.915 Earth years, equivalent to over 35,000 Earth days or nearly 87,000 days on the gas giant itself.

Ice Giant:

    The Ice giant, a significant celestial body in the solar system, boasts a considerable mass approximately 14 times that of Earth. Comprised primarily of water and methane ices, this planet is situated at the farthest distance from the sun, resulting in an average global temperature of -249 degrees Celsius. Despite its substantial mass, the Ice giant experiences relatively low gravity, approximately nine times greater than Earth's gravity. With a day lasting nearly seventeen hours, it completes a full rotation on its axis in a moderate timeframe. As for its orbital period, the Ice giant takes approximately 759 Earth years to complete one revolution around the sun, equating to a staggering 395,046 days on the Ice giant itself. Within its celestial domain, the Ice giant is accompanied by two major moons and nineteen minor moons, contributing to the dynamics of its gravitational influence.

The Amasa Belt:

    The Amasa Belt, spanning from approximately 2.7 AU to 4.1 AU from the sun, is a vast ring of asteroids. Within this belt, the majority of asteroids exhibit orbital eccentricities below 0.4 and inclinations less than 30 degrees. The distribution of asteroid orbits is characterized by a peak eccentricity of around 0.07 and an inclination below 4 degrees. While most asteroids follow relatively circular orbits aligned with the ecliptic plane, there are exceptions with highly eccentric and non-planar trajectories. The Amasa Belt has a total mass approximately three percent that of Earth's moon. Asteroids within the belt can be classified into three distinct categories. The largest proportion, accounting for 71% of asteroids, falls under the C-Class classification. C-Class asteroids are rich in volatile compounds and have low albedo due to their carbon-rich composition, along with rocks and minerals.

    Asteroids can be classified into three distinct categories based on their composition and spectral characteristics. The majority, 71% of asteroids, belong to the C-Class classification. C-Class asteroids are characterized by their volatile-rich nature and exhibit a very low albedo. This is mainly due to the presence of carbon in their composition, along with rocks and minerals. The second most common classification is the S-Type, which encompasses 17.5% of asteroids. S-Type asteroids are moderately bright and typically have an albedo of 0.20. They are primarily composed of iron- and magnesium-silicates, giving them their distinct spectral signature. Lastly, the M-Type asteroids make up 11.5% of the asteroid population. M-Type asteroids are identified by their spectral class, which indicates higher concentrations of metals such as iron and nickel compared to other asteroid classes.
    Within the Amasa Belt, a region populated by asteroids, there exists a small group of dwarf planets. The first is a rocky dwarf planet with a semi-major axis of 2.86 AU, placing it closer to the sun than the other two. Accompanying this rocky dwarf planet is a single small moon. This particular dwarf planet holds the title of being the largest object within the Amasa Belt, although its mass is only 1.2% that of Earth's moon. Slightly further out, at a distance of 3.47 AU from the sun, lies an icy dwarf planet. Despite its relatively small size, it is recognized as the smallest dwarf planet within the Amasa Belt. Its mass measures only 0.3% that of Earth's moon. Lastly, positioned as the outermost dwarf planet within the Amasa Belt, is a celestial body with a semi-major axis of 4.062 AU. This dwarf planet boasts a mass of approximately 0.4%

The Debris Disk:

    The Debris Disk, unlike the Amasa Belt, extends much farther from the sun and is significantly larger in scale. Resembling a doughnut-shaped band, this expansive region consists of numerous asteroids and dwarf planets. The inner boundary of the Debris Disk is located at a distance of 101.68 AU from the sun, while its outer boundary extends to 123.18 AU. This vast expanse encompasses a substantial volume, measuring over 256 million cubic astronomical units. In terms of mass, the Debris Disk surpasses the Amasa Belt, weighing approximately 7.44 times the mass of Earth's moon. that of Earth's moon. Within the expansive Debris Disk, five dwarf planets have taken up their orbits. The innermost and largest dwarf planet within the Debris Disk boasts a mass equivalent to 20% of Earth's moon. Orbiting at a distance of 101.7 AU from the sun, this dwarf planet possesses two moons and is adorned with a small set of rings. Moving slightly further out, we encounter a diminutive dwarf planet with a mass merely 1% that of Earth's moon. This small celestial body orbits at a distance of 106.81 AU from the sun. Another compact dwarf planet resides within the Debris Disk, with a mass measuring 9% that of Earth's moon. Its semi-major axis spans 112.6 AU. Presenting a distinct icy composition, the third dwarf planet within the Debris Disk boasts a noteworthy feature—an extensive system of planetary rings. With an axial tilt nearing 90 degrees, it exhibits relative brightness in the night sky. However, it remains just shy of being visible to the naked eye. This icy dwarf planet possesses a mass equivalent to 0.06 lunar masses and gracefully orbits at a distance of 120.03 AU. Lastly, we encounter the outermost dwarf planet, which maintains a semi-major axis spanning 123.15 AU. With a mass equivalent to 0.12 lunar masses, this celestial body marks the conclusion of the five dwarf planets residing within the Debris Disk.