You heard in the globular cluster lesson that such objects are good tracers of our galaxy’s size and form. This means that, because these clusters of stars are part of our galaxy, their dispersion throughout space aids in defining the galaxy’s borders. Because star clusters are massive and bright, they stand out against the background and are easy to notice even from afar.
In this scenario, an analogy might be to think of them as the city’s biggest skyscrapers. These tall structures are easily visible from a distance, allowing you to estimate your distance from the city. You may also determine the size of a city by counting how many buildings it has and how far apart they are.
Harlow Shapley was using the Milky Way’s nebulae to acquire a deeper understanding of the galaxy. He mapped their placements on a two-dimensional chart after measuring their positions and distances. In the two-dimensional plot below, I’ve recreated his work using recent data for the ranges and positions of all known star clusters.
Today in this article we are going to know What is the relationship between globular clusters and milky way? So, without further ado, let us get straight into the matter!
What is the definition of a globular cluster?
Globular clusters are densely packed, symmetrical groups of stars that orbit most spiral galaxies in their wide stellar halos. Globular clusters are assumed to have originated early in the history of the galaxy since they include some of the galaxy’s oldest stars.
Could it be that a spiral galaxy like our Milky Way was once an amorphous cloud of gas and dust when it was first forming? Could the universe’s initial stars have become globular clusters? Could these clusters have remained in the halo surrounding a galaxy’s core as the remainder of the spinning galaxy flattened out and produced spiral arms? That scenario would explain why globular clusters orbit in the halo of a galaxy and contain the galaxy’s oldest stars.
However, no one knows for sure how globular clusters evolved or what role, if any, they had in the evolution of galaxies. We do know that globular clusters are the oldest, largest, and most massive star clusters, as well as the oldest stars.
Their age is shown by the virtually complete absence of metals, or elements heavier than hydrogen and helium, which were present in the early cosmos before the birth of stars and galaxies. The heavier materials were forged within the confines of starships.
Clusters that are open
Stars in open clusters most likely originated from the same nebula at approximately the same time. These clusters, which include dozens or hundreds of stars, are significantly smaller than globular clusters and have irregular rather than spherical forms.
Open clusters are also generally younger than globulars, and they are frequently rich in gas between the stars. The Milky Way has around 1,000 known open clusters, but scientists believe the true number might be 10 times greater.
This is due to the fact that they prefer to live in the dense portion of the galactic disc, where the density of stars, gas, and dust prevents us from seeing everything there is to view.
Because of their position, passing stars and other objects tend to drive open clusters apart over extended periods of time. As a result, the majority of open clusters in the Milky Way are less than a billion years old, with older clusters found further from the galactic centre.
Because they are generally made up of young stars, open clusters serve as valuable laboratories for studying star evolution.
Open clusters are one method for measuring distances in space. Because all of the stars in the cluster have the same age, the major distinction between them is established by their masses.
The mass of a star influences its hue in middle-age: heavier stars are brighter and bluer, while lower-mass stars are redder. Mapping the apparent brightness of each colour star in a cluster and comparing it to the known quantity of light radiated by those stars allows us to determine how far that light travelled to reach us. This is referred to as main sequence fitting.
An association is a collection of extremely young stars, generally containing 5 to 50 hot, brilliant O and B stars dispersed across a 100–500 light-year-diameter region of space.
For example, the majority of the stars in the constellation Orion belong to one of the closest stellar associations. There are hundreds to thousands of low-mass stars in associations, but they are much fainter and less visible.
The existence of extremely hot, bright stars in the association suggests that star creation occurred within the previous million years or so.
Because O stars live their whole lifetimes in less than a million years, they would be extinct unless star creation occurred lately. As a result, it is not unexpected that associations are discovered in areas rich in the gas and dust needed to create new stars.
It’s as if you’re looking at a brand new structure that’s still surrounded by some of the materials used to create it, and the landscape is still exhibiting traces of construction.
However, because associations, like regular open clusters, are located in regions filled by dusty interstellar matter, many are concealed from our perspective.
Clusters of Globular Objects
Globular clusters were named by the fact that they are almost symmetrical spherical systems of hundreds of thousands of stars. Omega Centauri, located around 16,000 light-years distant and containing several million stars, is our Galaxy’s most largest globular cluster (Figure 1).
It’s worth noting that the brightest stars in this cluster are red giants that have already passed through the main-sequence phase of their development and are red-orange in hue. The surface temperatures of these stars are typically about 4000 K. Globular clusters, as we will discover, are among the earliest components of our Milky Way Galaxy.
What is it like to live within a globular cluster? The stars would be approximately a million times closer together in the dense core regions than in our own neighbourhood.
If Earth were to circle one of the core stars in a globular cluster, the nearest stars would be light-months away rather than light-years. They would still be visible as points of light, but they would be far brighter than any of the stars we see in our own sky. The Milky Way would most likely be impossible to discern through the cluster’s intense cloud of brightness.
In our Galaxy, around 150 globular clusters have been discovered. The vast majority of them are contained inside a spherical halo (or cloud) that surrounds the flat disc produced by the vast majority of our Galaxy’s stars.
All of the globular clusters are extremely far from the Sun, with some reaching distances of 60,000 light-years or more from the Milky Way’s main disc. Globular star clusters have sizes ranging from 50 to more than 450 light-years.
Must read for more information
We looked examined the connections between the structural characteristics of the Milky Way’s globular clusters, their internal dynamical phases, and the proportion of mass lost due to tidal forces (disruption). The Milky Way gravitational field has long been thought to have a significant influence in the mass loss process of globular clusters during their lives.
FAQ related to Globular clusters and the Milky way
Q- What are the similarities between globular clusters and the Milky Way?
Ans- In a nutshell, globular clusters are spherical groups of stars that spin in the stellar halo of spiral galaxies. Around 150 globulars may be found in our Milky Way galaxy, including some of the galaxy’s oldest stars.
Q- Is the Milky Way a globular cluster of stars?
Ans- The Milky Way’s core is home to two giants: the galaxy’s largest hole and a cluster of trillions of stars that is denser but more massive than any other star cluster in the galaxy. Nuclear star clusters are the thickest star clusters in the universe, and they can be found in many galaxies.