Milky Way Galaxy from Earth, Shape, Types, Map, Black Hole

Milky Way Galaxy

Milky Way Galaxy:  The Milky Way Galaxy, where we live is a barred spiral galaxy with at least 100 billion stars. It is about 100,000 light years wide and 1000 light years thick, with a central bulge that has a diameter of around 10000 light years. Our solar system is about a third of the way from the center toward the edge. If we were in the bulge, we could see a million stars as bright as Sirius at night, making it much brighter than day. The Sun and solar system are located within the 1000 light year thick disk and are about 95 light years from the central plane.

Milky Way Our Galaxy

There are few places on earth where we can even see the dusty bands of the Milky Way. Dust, gas, energy, a Solar System, and stars make up the Milky Way Galaxy. A spiral galaxy looks like a spinning wheel from above, and our Milky Way has about 100 billion stars. The planets orbit the Sun, which also orbits the Milky Way. It takes the Sun 250 million years to reach the center of our galaxy. There are billions of galaxies in the universe, but we can only see two or three with the naked eye. The closest one is Andromeda, which is moving toward us. Scientists believe Andromeda and the Milky Way could collide in about 4.5 billion years.

Milky Way Galaxy Size

• The Milky Way is huge, about 100,000 light-years across, and is around 13.6 billion years old.
• At the center of the Milky Way is a supermassive black hole called Sagittarius A. Everything in the galaxy orbits around it
• Surrounding Sagittarius A is a dense area of gas, dust, and stars called the galactic bulge. Beyond this is the galactic disc, which contains billions of stars, including our Sun.
•  The Sun is far from the galaxy’s center and takes about 230 million years to complete one orbit around it.
• The nearest galaxy to us is Andromeda, located about 2.5 million light-years away.

Milky Way Galaxy Black Hole

In the 1940s, Isaac Newton predicted the existence of a black hole. NASA scientists later discovered a massive black hole in the Milky Way Galaxy. The black hole was seen to be erupting with hot bubbles and bright gas. This black hole is approximately 900 million light-years from Earth. The black holes consume the stars or solar systems that surround them. The black hole in the Milky Way Galaxy is the size of billions of suns. Two or more black holes are fairly common. An astronomer recently predicted that the Milky Way Galaxy may contain more than one black hole.

Milky Way Galaxy Stars

A star is a huge, glowing ball of gas and dust held together by gravity. They are mostly made of hydrogen and helium. Stars come in different sizes, masses, and temperatures. A star’s color depends on its temperature: the hottest stars look blue, while the coolest stars look red.

Birth and Death of a Star

Stars are born from clouds of gas and dust called nebulae. Gravity causes dense areas in the nebula to collapse, forming a protostar. As the protostar condenses, nuclear fusion begins, creating a star. This fusion releases a lot of energy, making stars hot and bright. We already know that stars are made up of Helium and Hydrogen. As stars move toward the ends of their lives, much of the hydrogen gets converted into helium. Helium sinks to the star’s core, raising the star’s temperature. The hot interior core raises the temperature of the surrounding gases. As a result, the outer shell of hot gases expands, and the star changes colour to form a Red Giant star. What happens to the star now depends on its mass.

When a star has a low mass similar to Earth’s mass, it becomes a white dwarf. As nuclear fusion stops, the star’s core contracts, creating a very dense body called a white dwarf. Eventually, it stops emitting heat and light and becomes a black dwarf. For massive stars, they explode at the end of their life in an event called a supernova. This explosion leaves behind the core. If the core is between 1.5 and 3 times the mass of the Sun, it becomes a neutron star. If it’s more than 3 solar masses, it can form a black hole. Black holes are incredibly dense areas in space with such strong gravity that even light can’t escape them. The boundary beyond which nothing can escape a black hole is called the event horizon.

Milky Way Galaxy UPSC

Event Horizon Telescope is an international collaboration of a group of observatories. It aims to capture images of black holes. In 2019, it released the first-ever image of a black hole. The black hole was located in the centre of galaxy M87. Scientists from the Event Horizon Telescope (EHT) facility recently revealed the first image of the Sagittarius A* black hole at the centre of our galaxy, the Milky Way.

Nearly all galaxies have these massive black holes at their centres, where light and matter cannot escape, making images of them extremely difficult. The black hole was dubbed “the gentle giant in the centre of our galaxy” by researchers.

The Expansion of the Universe is a critical concept for the UPSC science and technology section. Both Indian and global scientists are conducting extensive research in this field to determine how the universe began billions of years ago. In this article, you will learn about the Milky Way and galaxies in a nutshell in preparation for the UPSC IAS exam.

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