Universe Related Terms

The distance between the Sun and Earth is 150 Million km. When you are trying to tell this to somebody, it gets quite tiring just saying 150 Million km. So the scientists have shortened this distance to 1 AU(Astronomical Unit). Now in today’s blog, we are going to discuss a lot of terms or words related to our Universe.

1.       Star – Stars are large masses of hot boiling plasma. They are mainly composed of Hydrogen and Helium. They are formed from the dust clouds of dead stars or planets. Stars are of many types –

1.       Neutron Star – Neutron stars are the smallest type of stars. They are formed from the remains of a giant star. Neutron stars have one of the strongest gravities in the universe. They are the size of a city (approx. 20km).

2.       Red Dwarfs – Red Dwarfs are the most common type of stars in the universe. They are small and quite cool. Red Dwarfs are also the stars that live the longest. They live so long because they glow very dimly. This dim glow requires very little Hydrogen to produce. Thus they have only lived a fraction of their life. Red Dwarfs can live up to 10 Trillion years.

3.       White dwarfs – White Dwarfs are another variant of stars. When a small star like our sun dies, it doesn’t die with an explosion but a whimper. Medium stars like our Sun don’t have enough energy to explode. They grow to their full size and then just evaporate leaving their core behind. This core then turns into a white dwarf.

4.       Black Dwarf – As we discussed White Dwarfs now; when White Dwarfs also die, they go away with a whimper. When the White Dwarfs die, they turn into Black Dwarfs. Black Dwarfs are very cool since they have lost a lot of their heat.

5.       Yellow Dwarf – Yellow Dwarfs are one of the largest types of Dwarf stars. They are medium in size and are halfway their lifespan. Our Sun is a yellow dwarf star.

6.       Brown Dwarf – Brown Dwarfs are stars that are 15 – 80 times the size of Jupiter. They are also called Half Stars.

7.       Giant stars – Giant Stars are those stars that are more than 8 times heavier than our sun. Giant stars are of Red, Orange, Yellow, and Blue. They are capable of producing a supernova on dying. Example – Rigel.

8.       Supergiant stars – Supergiant stars are those stars that are more than 20 – 30 times heavier than our sun. Supergiant stars are quite uncommon. They are absolutely capable of creating a supernova and a black hole. Eg – V Cephei.

9.       Hypergiants – Hypergiants are the bosses of the stars. They are the rarest type of stars. They are a hundred times heavier than our Sun. They are so large. The largest Hypergiant is Stephenson 2-18. This star is 2150 times larger than our Sun! They are so large that the temperature in their core is from 1 – 2 Billion Celsius thousand times are Sun’s surface temperature. They have the shortest lifespan in the universe. Their Supernova is so strong that they cause a supernova 5 – 10 times stronger than a normal supernova. This type of Supernova is called a hypernova. They can also create black holes and neutron stars.

10.   Pulsars – Pulsars are very fast-spinning stars that emit a lot of electromagnetic radiation from their poles.

11. Spectroscopy - All the stars are detected with a method called spectroscopy. Spectroscopy uses the wavelength provided by the star's light to tell the colour. Based on the colour we can tell the temperature, size, and chemical composition of the star.

These were the stars, let’s go to the planets –

1.       Planet – Planets are small celestial bodies formed from asteroids and other celestial bodies. They are usually made from rock or gas. The largest planet is Jupiter. Note – Planets only include the planets in our Solar Systems.

2.       Exoplanet – An exoplanet is a planet that doesn’t belong to our Solar system but resides in another. Such exoplanets can be way larger than our Solar System’s planets. The largest exoplanet is WASP 12-B. They can have rotation speeds at least 10 times that of Jupiter and Jupiter is the fastest rotating planet.

3.       Rogue Planets – Rogue Planets are those planets that have been separated from their Solar system due to a star or a black hole. Sometimes stars are just moving around and they come across a Solar system. The star’s gravitational pull can kick the planet out of its orbit.

4.       Dwarf Planets – Dwarf planets are those types of planets that are too small to be them and are too large to be an asteroid. There are 5 dwarf planets in our Solar System.

These were the planets, let’s go to the types of black holes –

1.       Stellar Mass Black Holes – Stellar Mass Black Holes are those types of black holes which are at least 4 – 20 times the mass of the sun. They are usually small and are very common throughout the Milky Way. They are formed after the death of a giant star, not Supergiant or Hypergiant.

2.       Supermassive Black Holes – Supermassive Black Holes are those black holes that are millions and billion times the mass of our sun. They are so large that the largest Black Hole discovered is TON 618. This monster has a diameter of 390 Billion Km!!!!!

3.       White Holes – White Holes are the type of Black Holes do the exact opposite of a Black Hole. Instead of eating the matter, they spew it out.

4.       Quasars – Quasars are very bright objects in the universe. They usually are supermassive black holes that have rays coming out of their poles. They have a disk of super-hot particles. This disk is called the accretion disk. The disk spins at a speed of half the speed of light.

Now, these were the types of Black Holes. Let’s go towards the Satellites

1.       Natural satellites – Natural Satellites are celestial bodies that are very small in size. They usually orbit a planet, an exoplanet, or a dwarf planet. They are small in size. Satellites are formed by the debris of their parent planet. They usually were born at the time of their parent's planet’s birth. Earth’s satellite is The Moon.

2.       Artificial satellites – Artificial satellites are man-made objects made by us humans to monitor the atmosphere, nearby space and locate nearby space debris and warn the Earth.

3.       Satellite galaxies – Yes, that is right. Even galaxies have their own satellites. They are a lot smaller than their parent galaxy. The Milky way’s largest and nearest satellite galaxy is the Large Magellanic Cloud.

Now, these were the satellites. Let’s go towards the Large Space Objects.

1.       Galaxies – Galaxies are large clusters of gravitationally controlled stars, black holes, solar systems, and dark matter. They range in all sizes. The largest galaxy is IC1101. This galaxy has a diameter of 3.9 Million light-years. The smallest galaxies are Segue 1 and Segue 3. They only have a thousand stars in them. They are the satellites of Milky Way. We live in a galaxy called the Milky Way with a diameter of 100,000 light-years.

2.       Groups – Groups are clusters of galaxies. Our Milky Way is in the Local group. The local group consists of 50 galaxies including Milky Way and Dwarf Galaxies.

3.       Superclusters – Superclusters are groups of groups. They are connected via various space fragments. Milky Way lies in the Laniakea Supercluster. This supercluster has a diameter of 500 Million light-years. This supercluster contains more than 100,000 galaxies. The largest supercluster is Caelum supercluster with 550,000 galaxies.

4.       Nebulae – Nebulae are large dust clouds created when a small star like the sun dies. Their diameters are measured in light-years.

5.       Observable Universe – The observable universe is the universe that we can see with the help of telescopes. The diameter of the Observable Universe is 92 Billion light-years.

6.       Multiverse – The Multiverse is a theory stating that our universe is in another type of mega – universe along with many other parallel universes. This mega – universe is called the multiverse.

Space Debris

1.       Asteroids – Asteroids are large rocks of elements and dust which are found in the Asteroid Belt and the Kuiper Belt. They range from a few meters to many hundreds of kilometers. The largest asteroid is Ceres.

2.       Meteors – Meteors are small versions of asteroids. They are just a few feet in length.

3.       Comets – Comets are small chunks of ice and dust. They revolve around the sun. They have a long tail behind them.

Dark Matter and Dark Energy

1.       Dark Matter – Dark Matter is a matter that is so dark, that it is undetectable by electromagnetic radiation or light. Dark matter is not proved yet. Scientists believe that Dark Matter is the reason behind unexplainable paths or routes of stars. Dark Matter makes up 20% of the Universe.

2.       Dark Energy – Dark Energy is currently an unexplainable type of energy. Some of us know that the Universe is constantly expanding. Since the Big Bang, the Universe has been expanding and this expansion has been accelerating. The expansion of the Universe is done by the Dark energy. Dark Energy was first questioned by Einstein. Dark energy is undetectable but accounts for 70% of the Universe.

The creation of the Universe

Big Bang – The Big Bang is believed to be the explosion that created the universe. The Big Bang is said to have occurred 13.8 billion years ago. When the Big Bang occurred, the universe was super tiny. Now it is constantly expanding.

Other terms

1.       Goldilocks zone – Goldilocks zone is the zone in a solar system where planets can survive. This zone is neither too hot nor too cold.

2.       Eclipses – Eclipses occur when two objects overshadow each other and come in a straight line.

How to measure these universal objects

1.       Meters – Small objects like meteors and comets are measured in meters.

2.       Kilometers – Objects like asteroids, planets, exoplanets, stars, dwarf stars, moons, black holes, quasars, pulsars are measured in km.

3.       Astronomical Unit – One astronomical unit is 150 Million km. AUs are used to measure the lengths of orbits and the diameter of orbits of planets.

4.       Light Years – One light-year is the distance traveled by light in 1 year. 1 light-year is almost 9.5 Trillion km. Star systems, nebulae, galaxies, groups, and superclusters are measured in light-years. 

Well, this article is finished. I want to thank you for reading my blog. My next blog is – Universe Size Comparison.