Scholar-Journalist
Astronomy For Beginners
By: Shrawaya Kapoor
Astronomy is the field of science that studies celestial bodies and natural phenomena in space.
The big bang theory is a physical theory that describes that the universe emerged from an infinitely hot and dense state that exploded approximately 13.8 billion years ago. The big bang theory was developed by the contributions of any scientists like Edwin Hubble and Georges Lemaitre.
Celestial bodies made of rock, dust, or gases that orbit a star and have a clear orbit are called planets. The planets in our solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The inner planets made of rock are called terrestrial planets and the outer planets made of gas are called jovian planets. Planets that are outside our solar system are called exoplanets, for example, TRAPPIST 1E.
Planets that do not orbit a star and drift in space are called rogue planets. Celestial bodies made out of hot gases [like hydrogen and helium] are called stars. Stars are classified by their temperature, size, and colour. Our sun is a G-type main-sequence star, The pole star [also known as Polaris] is a yellow-white supergiant star.
Stars from patterns that represent a character, object, or animal are known as constellations. When a star reaches the end of its lifetime it explodes, this process is called a supernova, the remains of stars are white dwarf stars, neutron stars, and black holes.
Celestial bodies made of rocks, dust, or ice that orbit a planet are called moons. They are often referred to as natural satellites. Some moons in our solar system are Callisto, Enceladus, Titania, etc.
Galaxies are huge clouds made out of gases [like hydrogen and helium] dark matter and dust. They stretch thousands of light years across. The galaxy we are currently in is the Milky Way and the nearest galaxy to it is the Andromeda [M31]. Nebulas are similar to galaxies but are smaller, they are made out of gases and dust. A nebula is formed after a supernova explosion. Some examples of nebulas are Cats eye nebula, Helix Nebula, etc.
Celestial bodies in space that have such a strong gravitational pull that not even light can escape them, are called Black holes. The black hole in the center of our galaxy is called Sagittarius A.
A neutron star is a collapsed core of a supergiant star, they are also one of the most dense objects in the universe. The nearest neutron star to Earth is the Vela pulsar.
The distance light travels in a year is called a light year. One light year is 9.46 trillion km. We use light years to denote very long distances in the universe.
The distance between the Earth and the Sun is called an astronomical unit. One astronomical unit is 149,597,870.7 km.
A parsec is also a unit of measurement in astronomy. One parsec is 3.26 light years.
Gravity is the universal force of attraction acting between all bodies of matter, It is the weakest fundamental force. It holds everything in our universe together. Space-time is the 4th dimensional fundamental fabric that combines space and time [this is theoretical]
1st dimension is just a point and has no length, width, or depth.
2nd dimension has length and width. It is shown on paper or computer screens.
3rd dimension has length, width and depth. This dimension is shown in everyday objects such as a football or TV.
4th dimension is space-time itself.
The Fermi paradox is a philosophical question in astronomy that asks why have we not encountered any signs of extraterrestrial life. This paradox is about discovering life beyond Earth.
A planet must have water, an atmosphere, land, and certain chemicals and must be in the habitable zone to harbor life.
Some habitable exoplanets near us are
TRAPPIST 1E is one of the seven earth-sized exoplanets in the TRAPPIST 1 star system, located 39 light years away.
Proxima Centauri B is the closest exoplanet to us but it receives ultraviolet rays from its star that are harmful to us.
Kepler 186F is 10 percent larger than Earth and is 500 light years away
Kepler 62F is 4 percent larger than Earth and is 1200 light years away.
Fun Facts
Stephenson 2 18 is the largest star in the universe.
The Milky Way and Andromeda galaxy are going to collide in 2-3 billion years.
The average temperature of the universe is -270.42 Celcius. Phoenix A is the biggest black hole in the universe.
The nearest star system, Alpha Centauri is 4.2 light years away from us.
The sun is going to turn into a red giant star in 2-3 years.
A day on Venus is longer than its year.
Mars has the tallest mountain in our Solar system.
