Wednesday, February 21, 2024

Related Posts

What Is Astronomy?

Geography comes from two Greek words, GEO (Earth) and GRAPHY (description), meaning ‘description of the Earth.’ It’s about studying the Earth and its features.

Astronomy is the study of the universe. The universe includes all the celestial bodies we can see. It’s expanding, and there are a lot of stars in it.

A star is a celestial object with its own heat and light. Stars have a very long lifespan and go through different stages. Before becoming a star, there is a rarefied gas cloud.

When these gas clouds come together, they form dense clouds called Nebulae. When fusion starts in Nebulae through a process called nuclear fusion, stars are born.

Stars contain hydrogen that fuses into helium. They exist in a state called plasma. The color of a star depends on its surface temperature.

  1. Blue and white color → Young age → High temperature
  2. Orange color → Middle age → Moderate temperature
  3. Red color → Old age → Low temperature (6000°C)

The future of a star depends on its initial mass. A Red Giant is a star (like the Sun) that starts expanding when its hydrogen fuel is running out. If the Red Giant’s mass is less than 1.44 times the Sun’s mass, it becomes a White Dwarf, a small, shining object in its final stage. If it’s more, it becomes a Black Dwarf, a small, dark remnant when the star stops shining.

Case II: If the mass of the Red Giant is greater than 1.44 times the mass of the Sun, it will take the form of a Supernova.

  • Supernova (Abhinav Tara): In this stage, light elements like carbon transform into heavy elements like iron, causing the star to undergo an explosion. Therefore, it is called an explosive star or “Visphotak Tara.”

After the explosion, it takes the form of a Neutron Star.

  • Neutron Star (न्यूट्रॉन तारा): A Neutron Star is formed after a Supernova explosion. Its density increases, and its size becomes small. All components of Neutron Stars are organized in the form of neutrons.
  • Pulsar (पल्सर): This type of star keeps shining and dimming. It emits intense beams of electromagnetic waves, including rapid radio waves.
  • Quasar (क्वेसर): These are nearly the last stage of stars. Quasars have extremely high magnetic capabilities.
  • Black Hole (कृष्ण विवर): It has extremely high density and doesn’t let light pass through it. The discovery of Black Holes was made by Chandrasekhar. A star with a mass three times greater than that of the Sun becomes a Black Hole. Black Holes also have strong gravitational forces, attracting nearby matter and even light. Therefore, the end of stars is often in the form of a Black Hole.
  • Chandrasekhar Limit (चंद्रशेखर सीमा): This is the limit of 1.44 times the mass of the Sun. The fate of stars after the Red Giant stage depends on whether their mass crosses this limit.

Note: Subrahmanyan Chandrasekhar was awarded the Nobel Prize in Physics in 1983 for his contributions to astrophysics and the study of degenerate stars.

  • Galaxy (आकाशगंगा): In the universe, groups of stars are called galaxies. The shape of a galaxy is often spiral, with stars found along the arms of the spiral. As stars age, they move towards the center of the galaxy.
  • Super Cluster (सुपर क्लस्टर): A group of three galaxies is referred to as a Super Cluster. There are three such Super Clusters: Mandakini, Devyani, and NGC-M-33.
  • Andromeda Galaxy (देवयानी): It is the closest galaxy to us. Andromeda is about 2.2 million light-years away from our Milky Way galaxy.
  • Milky Way (मंदाकिनी): Our own galaxy, where the Solar System is located, is known as the Milky Way. It has a spiral shape, and the Orion Nebula is the coolest and brightest region in the Milky Way.

These celestial objects and phenomena offer a glimpse into the vast and intriguing world of astronomy and the universe.

  • तारामंडल (Galaxy): It has three rotating arms. When new stars are formed, they are on the outer arm, so the Sun is also on the outer arm. When stars enter the Red Giant phase, they move to the middle arm. In their final stage, stars enter the central arm. The central part of the Milky Way is called the bulge, where Black Holes are found, and they attract even dwarf and giant stars. The end of stars often occurs in the form of a Black Hole.
  • मंदाकिनी (Milky Way): It was first observed by Galileo. The Sun revolves around the center of the Milky Way in an anticlockwise direction at a speed of 250 km/sec. It takes about 25 crore years for the Sun to complete one revolution around the center. This period is also called a cosmic year. The nearest star to the Sun is Proxima Centauri.
  • तारामडंल (Star Cluster): Groups of stars located at a distance from the Sun are called star clusters. Currently, there are 89 known star clusters. The central and Hydra are the major star clusters, with Hydra being the largest.
  • ध्रुव तारा (Pole Star): It is always visible in the northern direction because it is situated above the north pole of the Earth. In ancient times, it was used to determine direction, so it is also called the Pole Star.
  • साइरस (Sirius): Known as the Day Star, it is the brightest star observed through Orion.
  • हैटर तारामण्डल (Orion): Resembling a hunter, it is also called Mrig. Sirius is located in the southwestern part of Orion.
  • वृहद सप्तर्षि (Ursa Major): A group of seven stars, and the upper star in this constellation is known as the Dhruv Tara (Pole Star).
  • लघु सप्तर्षि (Ursa Minor): Another group of seven stars, it is smaller in size compared to Ursa Major.
  • नक्षत्र (Constellation): Groups of stars near the Sun are called constellations. There are 27 constellations, and the Indian tradition adds Abhijit as the 28th constellation. The Sun passes through 2.25 constellations each month.
  • कुछ प्रमुख नक्षत्र (Some Major Constellations): Chitra, Hast, Vishakha, Shravan, Dhanishta, Magha, Adra, Anuradha, Rohini, etc.

These astronomical features provide insights into the arrangement, motion, and characteristics of celestial objects in our universe.

In simple English:

Origin of the Universe:
The theory of the origin of the universe, known as the Big Bang, was proposed by the Belgian priest Georges Lemaître. According to this theory, about 15 billion years ago, a very dense star underwent a massive explosion called the Big Bang. This explosion resulted in the creation of various fundamental particles like electrons (e–), protons (P+), neutrons (n0), neutrinos, etc. After the Big Bang, space was formed, and the measurement of time began.

These particles came together, forming stars. Groups of stars formed galaxies, and several galaxies combined to create a supercluster. The combination of many superclusters gives rise to the entire universe. The scientist Hubble discovered that the universe is expanding by observing distant galaxies through the telescope named after him.

Scientists believe that there might be a force assisting in the expansion of the universe. When this force diminishes, the universe might contract and return to its initial state, known as the Super Crunch.

Formation of the Solar System:
The region around the Sun and its celestial bodies, including planets, moons, asteroids, and comets, is called the solar system. Various theories have been proposed regarding its formation:

  1. Mono Star Theory: According to this theory, the solar system was formed from pieces of the Sun. Two scholars proposed this idea.
  • Gas Theory: Proposed by Kant, suggesting that the Sun’s rotation caused separation of its outer layers, forming planets. This theory was rejected.
  • Nebula Theory: Proposed by Laplace, stating that the outer part of the Sun cooled, and the separated material formed planets. This theory was also rejected because the structure of planets differs from the Sun.
  1. Dual Star Theory:In this theory, it is suggested that the solar system was formed from two stars. Two scholars proposed this idea.
  • Chamberlin: Proposed that a large star near the Sun caused its upper part to break, forming the solar system.
  • Jeans: Proposed a massive star near the Sun, and its gravitational forces separated the upper part of the Sun, forming planets. Both theories were rejected due to differences in the structure of planets compared to the Sun.
  • Double Star Theory:
  • Proposed by Lilliton, it suggests that the solar system formed from two stars outside the Sun.
  • One star exploded (went supernova), and its gravitational attraction brought it close to the Sun. This explosion led to the formation of planets, while the other star turned into a black hole.

This theory is widely accepted, and the current understanding is that the structure of the planets aligns with the remnants of the exploded star.

  • Solar System (Sauramandal):
  • Copernicus discovered the solar system.
  • The Sun is at the center of the solar system.
  • The planets revolve around the Sun in elliptical orbits.
  • Sauramandal consists of the Sun, planets, satellites, asteroids, comets, and celestial bodies.
  • The Sun:
  • The closest star to us in the solar system.
  • It is the main component of the solar system.
  • The Sun’s age is approximately 15 billion years, with 5 billion years already passed.
  • Located about 26,000 light-years away from the center of our galaxy, the Milky Way.
  • The Sun orbits the center of our galaxy at a speed of 250 km/s.
  • It takes around 25 crore years for the Sun to complete one orbit around the galactic center.
  • The diameter of the Sun is 13.92 lakh kilometers.
  • Sunlight takes about 8 minutes and 20 seconds to reach Earth.
  • The Sun is primarily composed of hydrogen and helium in plasma state.
  • The Sun rotates on its axis from east to west, with a rotation period of about 25 days near the equator.

On the basis of internal structure, the sun is divided into three parts:

i. Core: This is the central part of the sun. Its temperature is about 15 million degrees Celsius. Hydrogen atoms combine in this region, forming plasma. Nuclear fusion takes place here, producing immense energy.

ii. Radiative Zone: After nuclear fusion in the core, various types of radiation, such as X-rays and gamma rays, travel through the radiative zone. This zone extends outward from the core.

iii. Convective Zone: In this zone, cells of hydrogen gas circulate. The larger cells move inward, while the smaller cells move outward. Energy is transported through convection in this region.

Solar Flare: When there is an excess of energy in the core, it bursts out of the sun’s surface, forming a solar flare. These flares can reach the solar system and affect Earth. The temperature and energy of solar flares vary, influencing their impact.

Solar Spot & Sunspot: Sunspots are cooler areas on the sun’s surface caused by magnetic activity. They appear darker than their surroundings. The discovery of sunspots is credited to Galileo.

Sunspot Cycle: The solar activity, including sunspots, follows an 11-year cycle. In 2013, the 23rd solar cycle completed, and currently, the 24th cycle is ongoing. Each cycle sees about 100 solar events.

Magnetic Arc: When a sunspot forms, the magnetic strength in that area increases. These magnetic fields pull solar material towards them, creating what is known as a Magnetic Arc.

Outer Layers of the Sun: The sun has three outer layers:

i. Photosphere: The visible surface of the sun with a temperature of 6000°C.

ii. Chromosphere: Located above the photosphere, this layer has a temperature of 32,400°C and is responsible for the solar spicules.

iii. Corona: The outermost layer with a temperature of 2.7 million degrees Celsius. It is seen during solar eclipses.

Other Facts about the Sun:

  • The sun is composed mainly of hydrogen (75%) and helium (24%).
  • The sun’s mass is 332,000 times that of Earth.
  • The sun’s radius is 109 times that of Earth.
  • The sun’s gravitational pull is 28 times that of Earth.
  • The sun’s density is 20 times that of Earth.
  • The sun emits 10^26 joules of energy per second.
  • The sun rotates counterclockwise in the west-east direction.
  • The sun’s equatorial region completes one rotation in 25 days, while the polar region takes 31 days.
  • The average distance from the sun to Earth is 149.6 million kilometers.
  • Solar energy is generated through nuclear fusion in the sun’s core.

A planet is a celestial body that doesn’t have its own heat and light; it relies on the nearby star (like the Sun) for heat and light. It revolves around that star.

There used to be 9 planets, but now there are 8. Planets are divided into two types:

  1. Terrestrial Planets (Inner Planets): These planets are similar to Earth in density and are in solid form. They have no or fewer moons. There are four of them: Mercury, Venus, Earth, and Mars.
  2. Jovian Planets (Outer Planets): Also known as gas giants, they are similar in size to Jupiter. These planets are gaseous and have a greater density. There are more of these planets, including Jupiter, Saturn, Uranus, and Neptune.

Pluto: Pluto, initially considered the ninth planet, was reclassified as a dwarf planet by the International Astronomical Union (IAU) in 2006 due to its small size, unusual orbit, and overlap with the orbit of Neptune.

Satellites: Satellites do not have their own heat or light; they rely on the nearest planet or star for that. They revolve around their nearest planet. Satellites are of two types:

  1. Natural Satellites: These are moons, like Earth’s Moon.
  2. Artificial Satellites: Man-made satellites used for communication and weather forecasting.

Goldilocks Zone: It’s a space region where the conditions are just right for life. Earth is in the Goldilocks Zone, and there’s a possibility of life on Mars. Scientists sent a cotton plant to space to see if life could originate there.

In summary, planets are celestial bodies that revolve around stars, and there are two main types: terrestrial and jovian. Pluto is now considered a dwarf planet. Satellites can be natural (moons) or artificial (human-made). The Goldilocks Zone is where conditions for life are optimal, and Earth is in this zone.

Mercury (बुध ग्रह):

Mercury is named after the Roman messenger god. It’s the smallest and closest planet to the Sun. It doesn’t have an atmosphere, so it can’t trap heat. Consequently, temperatures on Mercury vary widely, reaching up to 420°C during the day and dropping to 180°C at night. Due to its lack of atmosphere, Mercury experiences the highest temperature differences among all planets.

Mercury doesn’t have any moons. Because it lacks an atmosphere, it can’t retain heat, and its surface is covered with large craters.

It completes one orbit around the Sun in 88 days, and its rotation period (day) lasts for about 58.6 days. Mercury is much smaller than Earth, being only 1/18th of Earth’s size.

Venus (शुक्र):

Venus is known for its thick atmosphere, primarily composed of carbon dioxide. This atmosphere traps heat, making Venus the hottest planet in our solar system. Its surface pressure is so high that it’s often referred to as the “Veiled planet.”

Venus is similar in size and density to Earth, earning it names like Earth’s sister or twin. It rotates on its axis in the opposite direction, causing the Sun to rise in the west. Venus completes one rotation in about 243 Earth days, but its day (from one sunrise to the next) is roughly 117 Earth days.

Venus doesn’t have any moons, and its atmosphere contains a significant amount of sulfuric acid.

Mars (मंगल):

Mars is often called the “Red Planet” due to its iron oxide-rich surface, giving it a reddish appearance. It has the most similarities to Earth, and scientists consider the possibility of life on Mars.

Mars has two small moons, Phobos and Deimos. It has the largest volcano in the solar system, Olympus Mons, and a canyon system, Valles Marineris.

A day on Mars is approximately 24.6 Earth hours, and it completes one orbit around the Sun in about 687 Earth days.

Jupiter (वृहस्पति):

Jupiter is the largest planet in our solar system, primarily composed of gases. It has a strong gravitational pull, often referred to as a “vacuum cleaner” for its ability to attract and capture space debris.

Jupiter has a vast system of rings and many moons, with Ganymede being the largest. Jupiter’s rotation is fast, completing one rotation in about 9.5 hours. It takes approximately 12 Earth years for Jupiter to orbit the Sun.

Jupiter’s atmosphere contains a high amount of hydrogen and helium. NASA’s Juno spacecraft was sent to study Jupiter, reaching the planet in 2016.

Saturn (शनि ग्रह):

Saturn is known for its prominent ring system, consisting of seven major rings labeled A to G. These rings are composed mostly of ice particles and dust.

Saturn has numerous moons, with Titan being the largest. Titan is unique for having a thick atmosphere and lakes of liquid methane and ethane on its surface.

Saturn’s low density means it would float in water if a sufficiently large ocean were available. A day on Saturn lasts about 10.7 Earth hours, and it takes approximately 29 Earth years to orbit the Sun.

Uranus (अरूण):

Uranus is an ice giant and rotates on its side, likely due to a collision with a massive object. It has a bluish-green appearance due to the presence of methane in its atmosphere.

Uranus has a system of rings and 27 known moons, with Titania being the largest. It completes one rotation in about 17.24 Earth hours and orbits the Sun roughly every 84 Earth years.

Neptune (वरूण):

Neptune, the farthest planet from the Sun, is similar to Uranus in composition. It has a blue color, primarily from methane in its atmosphere.

Neptune has a Great Dark Spot, similar to Jupiter’s Great Red Spot, and a fast rotation, completing one day in about 16 Earth hours. It takes approximately 165 Earth years to orbit the Sun.

Neptune has 13 known moons, with Triton being the largest. Triton is unique for its retrograde orbit and geysers erupting from beneath its icy surface.

Revolution and Rotation:

Revolution refers to a planet’s orbit around the Sun, determining its year, while rotation is the spinning of a planet around its axis, causing day and night. Each planet has its own period of revolution and rotation, influencing its climate and other characteristics.

The first satellite sent by humans went into Earth’s orbit, and the first satellite sent to another planet, Venus, was sent to orbit around Venus. It stays in a solid state.

Small planets (Asteroids) move in the orbits of Mars and Jupiter. They are broken parts of planets, but due to the gravitational pull of Mars and Jupiter, they are trapped between these two planets.

The dwarf planet Pluto used to orbit in the western to eastern (elongated) orbit in 2006. It was reclassified from the category of planets to the category of dwarf planets. Pluto, along with other similar dwarf planets, was placed in a new category called Plutoids.

Ceres is the largest and the brightest dwarf planet, while Vesta, Europa, Ida, Apollo, and Davida are other dwarf planets.

Meteoroids pull the small planets due to the gravitational force of Mars and increase in size. They enter Earth’s atmosphere and start burning due to friction, creating what we call a shooting star or falling star. When a meteoroid falls on Earth, it is called a meteorite. The impact of meteorites has various effects:

  1. When they enter the atmosphere, the friction causes them to turn into dust, resulting in red rain.
  2. Their entry into the atmosphere causes burning, leading to an increase in temperature and global warming.
  3. The Earth’s mass increases, affecting gravitational pull.
  4. The rotation speed of Earth decreases.

Bolide is a term used for a meteoroid that falls in the opposite direction of Earth’s rotation. It appears brighter, and when it lands on Earth, it is called a tektite.

Effects of meteorites:

  1. Their entry creates dust, causing red rain.
  2. Burning meteorites raise temperatures and contribute to global warming.
  3. Their impact increases Earth’s mass, affecting gravitational pull.
  4. Earth’s rotation speed decreases.

Comets are made of dust and ice and follow a path around the sun. When they approach the sun, they heat up and may start glowing or burning. Their tail is always opposite to the direction of the sun.

Comets have three parts:

  1. Nucleus: The main solid part of the comet made of dust, ice, and other solid substances.
  2. Coma: The top part of the comet, releasing dense clouds of water, carbon dioxide, and other gases.
  3. Tail: The part behind the comet, consisting of gas remnants.

Tycho Brahe discovered the comet’s tail. The tail is always in the opposite direction to the sun.

Tolomey said the sun revolves around the Earth. Copernicus discovered the solar system and explained that Earth and other planets revolve around the sun. Kepler explained the motion of planets, stating that planets revolve in elliptical orbits and move faster when closer to the sun. Galileo, with the invention of the telescope, confirmed these theories. Hubble’s observations expanded our understanding of the universe.

The first spacecraft sent by humans went into Earth’s orbit, which is circular. The first spacecraft sent to another planet was Venus, sent to Venus. It stays in a solid state.

Asteroids, small planets, move in the orbits of Mars and Jupiter. They are broken parts of planets, but due to the gravitational pull of Mars and Jupiter, they form a belt between these two planets.

The asteroid Ceres orbits in an elongated (oval-shaped) path from west to east in the asteroid belt.

In 2006, Pluto was reclassified from the category of planets and placed in the category of dwarf planets, and similar small dwarf planets were given a new category called “plutoids.”

Ceres is the largest and brightest dwarf planet, while Vesta, Europa, Ida, Apollo, and Davida are other dwarf planets.

Meteoroids, small asteroids, are pulled by the gravitational force of Mars and move forward on their own. These meteoroids enter Earth’s atmosphere. Due to friction in the atmosphere, they start burning and are called shooting stars or falling stars on Earth. When a meteoroid falls on Earth, it is called a meteorite. Meteorite impacts create craters, like the one in Lonar Lake in India, Natal in South Africa, and the largest one in Arizona, USA.

The impact of meteorites:

  1. When they enter the atmosphere, the friction causes them to turn into dust, creating red rain.
  2. Their entry causes burning, increasing temperatures and contributing to global warming.
  3. Their impact increases Earth’s mass, leading to increased gravitational attraction.
  4. Their impact reduces Earth’s rotation speed. Earth used to rotate in 18 hours, but due to meteorite impacts, it now takes 24 hours.

Comets, made of dust and ice, follow a path in the shape of a parabola around the Sun. When they approach the Sun, they heat up, producing a glowing tail opposite to the Sun.

Comets have three parts:

  1. Nucleus: The main solid part of the comet made of dust, ice, and other solid substances.
  2. Coma: The top part of the comet, from which dense clouds of water, carbon dioxide, and other gases are continuously released.
  3. Tail: The part behind the comet, consisting of gas remnants in the form of a trail.

Tycho Brahe discovered the tail of the comet, and comets always have their tails opposite to the Sun.

The three parts of a comet are important because they help understand the composition and behavior of comets.

Scientists like Ptolemy, Copernicus, Kepler, Galileo, and Hubble have contributed to our understanding of the solar system and the universe.

  • Earth: Earth is the only planet where life is possible. Due to its abundance of water, it is called the Blue Planet. It has 71% water and 29% land.
  • Earth’s density is the highest, at 5 gm/cm3.
  • Among the five planets with active volcanoes in the solar system, Earth is one of them, along with Jupiter, Saturn, Venus, and Varuna.
  • Earth is spherical in shape, referred to as a globe.
  • The equatorial diameter of Earth is 12,756 km, while the polar diameter is 12,714 km, resulting in a difference of 42 km.
  • Earth’s axial tilt is 23.5°, causing seasons and variations in day and night lengths.
  • Rotation: Earth rotates on its axis from west to east, completing one rotation in 24 hours (23 hours, 56 minutes, 43 seconds). Rotation results in phenomena like day and night, the generation of winds (breeze), the creation of jet streams, and the Coriolis effect.
  • Orbit: Earth completes its orbit around the Sun in 365 days, 5 hours, 48 minutes, and 46 seconds, known as a solar year. This orbit leads to events like the changing of seasons, the variation in day length, and the occurrence of days and nights at the poles.
  • Aphelion: When Earth is farthest from the Sun (147 million km), occurring around July 4th.
  • Perihelion: When Earth is closest to the Sun (152.1 million km), occurring around January 3rd.
  • Aphelion and perihelion create an imaginary line called the aphelion line.
  • Astronomical Unit (AU): The average distance between the Earth and the Sun is approximately 150 million km (149.6 million km), and this distance is defined as one astronomical unit. Light from the Sun takes about 8 minutes and 16 seconds to reach Earth, while it takes about 1.28 seconds to reach from the Moon.

These characteristics and movements of Earth contribute to the unique features of our planet and its ability to support life.

  • Moon: The Moon is referred to as the “Jeevashma” (living being) of the Earth, and it is often called the “Night Queen.” The study of the Moon is known as selenology.
  • Due to the absence of an atmosphere on the Moon, there is a significant temperature difference between day and night. Daytime temperatures can reach 100°C, while nighttime temperatures drop to -180°C.
  • The lack of an atmosphere also leads to the formation of large impact craters on the Moon’s surface, creating a landscape with prominent features called mare (seas) and highlands.
  • The absence of an atmosphere on the Moon means that sound is not transmitted, and the sky appears black.
  • The average distance between the Moon and Earth is 384,000 km, and it takes about 1-3 seconds for light to travel from the Moon to Earth.
  • Apogee and Perigee: When the Moon is farthest from Earth, it is called apogee, and when it is closest, it is called perigee.
  • Super Moon: When the Moon comes closest to Earth, it appears larger, and this phenomenon is called a Super Moon. We see about 59% of the Moon’s surface from Earth during this time.
  • Phases of the Moon: The changing appearance of the Moon, called lunar phases, is due to its orbit around Earth. There are different phases like New Moon (Amavasya) and Full Moon (Purnima).
  • Blue Moon: When two Full Moons occur in a calendar month, the second one is called a Blue Moon. For example, if the first Full Moon is on August 2, 2012, and the second one is on August 29, 2012.
  • The Moon has phases similar to the phases of the Moon, and both Venus and Mercury exhibit crescent, quarter, and gibbous phases.
  • The Moon always shows the same face to Earth due to synchronous rotation.
  • Lunar Exploration: The first living being to travel to the Moon was a dog named Laika. Humans first set foot on the Moon on July 21, 1969, during the Apollo 11 mission, with astronauts Neil Armstrong and Buzz Aldrin.
  • Eclipses: When an astronomical body is obscured, partially or entirely, by another object, it is called an eclipse.
  • Solar Eclipse: When the Moon comes between the Sun and Earth, blocking the Sun’s view, it is called a solar eclipse. A total solar eclipse results in the appearance of a ring of sunlight known as the “diamond ring.”
  • Lunar Eclipse: When Earth comes between the Sun and the Moon, causing Earth’s shadow to fall on the Moon, it is called a lunar eclipse. A total lunar eclipse gives the Moon a reddish hue, known as the “Blood Moon.”
  • Transit: The passage of a planet across the face of the Sun as seen from Earth is called a transit. Mercury and Venus can undergo transits.

The Moon’s unique characteristics and its impact on Earth have made it a fascinating celestial body for exploration and study.


Please enter your comment!
Please enter your name here

Popular Articles