Galaxy questions and answers: All about Galaxy

Galaxy

In this article, you can find galaxy questions with their short and considerable answers. These questions contain a proper and exact answer with some interesting facts about the galaxy.

So by reading these questions, you must find some amazing facts about the galaxies in our universe. Here starts with the first and simple one:-

What is Galaxy?

Galaxy is a system of millions to trillions of stars and their solar systems, interstellar gas, dust, and dark matter bound together by gravity. Some of the galaxies have a few hundred million stars, whereas some galaxies have more than a hundred trillion stars.

 

Name of Our Galaxy

What is the name of the galaxy we live in?

We live on a planet whose name is Earth. Earth is a part of the Milky way galaxy. So the name of the galaxy we live in is ‘Milky Way’.  ➡ (More about Milky Way Galaxy)

Milky Way galaxy is also a part of a group of galaxies called the Local Group. The diameter of the milky way galaxy is approximately 150,000 light-years, whereas the mass is about 1.5 trillion times the mass of the sun. 

 

Largest known Galaxy

What is the largest known galaxy in the universe?

There are approximately 100 billion galaxies in the universe and IC 1101 is the largest known galaxy of our Universe. 

largest galaxy

Largest galaxy: Not real image

The approximate diameter of this galaxy is 6,000,000 light-years, whereas the diameter of our galaxy Milky Way is just 150,000 light-years. The mass of this galaxy is equivalent to 100 trillion stars

IC 1101 is a supergiant elliptical galaxy that exists in the center of a group of galaxies Abell 2029. The distance of IC 1101 galaxy from the earth is 1100 million light-years. 

 

Brightest Galaxy

What is the brightest galaxy in the universe?

In 2015 NASA’s spacecraft WISE discovered the brightest galaxy in the Universe. This galaxy is categorized into a new group of objects known as ‘extremely luminous infrared galaxies, or ELIRGs’. The name of the galaxy is WISE J224607.57-052635.0. WISE is the acronym of ‘wide-field infrared survey explorer’.

The galaxy WISE J224607.57-052635.0 has a brightness of more than 300 trillion suns. The main source of the intense light from this galaxy is the supermassive black hole that exists at its center and it releases more than 10000 times energy compare to our galaxy Milky-Way.

 

Types of Galaxies

How many types of galaxies are there in the universe?

There are mainly four types of galaxies in the Universe, classified according to their shape and appearance. This classification of the galaxies is called ‘Hubble Sequence’. So according to Hubble Sequence four types of galaxies are ‘spiral, barred spiral, elliptical, and irregular’.

Spiral galaxy consists of a bulge at the center, a disc, and a halo with spiral arms. Here spiral arms are wrapped around the bulge of stars. Spiral arms consist the most of the gas and dust that form new stars in the arm, whereas bulge contains older stars.

Barred spiral galaxies also have spiral arms but these arms are connected with a bar of stars. The arms of the bar-shaped stars extend outwards from the center. Our Milky Way galaxy is a barred spiral galaxy that contains two hundred billion (2 ×1011) stars.

Elliptical galaxies have a shape of spherical to elongated ovals. According to Hubble Sequence classification spherical shape galaxies denoted by E0, whereas the most oval-shaped galaxies denoted by E7.

Irregular galaxies do not fall in the categories of the Hubble Sequence, so these galaxies have no distinct shape.

 

Age of Galaxy

How old are galaxies?

According to many astronomers, our universe is 13.8 billion years old. Most galaxies started developing when the universe itself was in the young stage. 

So many galaxies are older than 13 billion years. It takes millions of years to develop a galaxy, so they may be as younger as they get their existence. The youngest known galaxy ‘I Zwicky 18′ is 500 million years old. Astronomers believe that our milky way galaxy is almost 12.8 billion years old. 

age of galaxies

Age Facts: Not to Scale

Oldest and Most Distant Galaxy

What is the name of the oldest galaxy?

How far is the most distant galaxy?

In 2016 by some astronomers, during a survey and data studying with Hubble Space Telescope’s CANDELS and Spitzer Space Telescope’s GOODS-North, they identified a galaxy which gets existence just after 400 million years after the big bang. It means the age of this galaxy is around 13.4 billion years and it is the oldest galaxy in the known universe.

The name of this oldest galaxy is GN-z11. Light rays from this galaxy take 13.4 billion years to reach on the earth and according to researchers, this is the most time taken by any light rays to reach on earth. So the galaxy GN-z11 is also the most known distant galaxy in the universe.

The size of the GN-z11 is only 25% of our Milky Way galaxy and the mass is only 1% of the Milky Way. Due to the expansion of the universe its distance from the earth is approximately 32 billion light-years. 

 

Intergalactic space

What is intergalactic space?

The empty space between galaxies is known as intergalactic space and it is filled with faint gases. These gases are so empty and have an average density of just less than “1 atom per cubic meter”

intergalactic space

The present material of intergalactic space is called the intergalactic medium (IGM). These mediums are mostly filled with ionized hydrogen but also some rare amounts of higher elements like carbon, oxygen, and silicon are present. The intergalactic space between the Milky Way galaxy and its neighbor Andromeda galaxy is approximately 2.5 million light-years


 

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