8 Biggest Stars In The Universe [Insanely Big]

Biggest Stars In The Universe [Insanely Big]

Our galaxy is filled with various massive stars of varying sizes. Stars are the most fascinating celestial objects out there that are often seen as bright dots scattered across the sky. Knowing their size would leave people stunned.

Read on to know more about big stars in the universe. Trust us, some of these are so big, their size will leave you baffled!

Are These Stars Bigger Than The Sun?

When we talk about stars, the first one that comes to mind is the Sun. It is a well-known fact that the Sun is the largest object in our solar system. But it isn’t necessarily the largest star out there. The size of a star is always calculated in comparison to the size of our Sun.

They can be calculated in terms of mass or diameter. Keep in mind that stars keep varying in size all the time. Scientists can never state the exact size of an individual star in the sky.

We can spot various stars through our windows if we use a powerful telescope or a pair of binoculars. But even when viewed through a telescope, they are extremely bright and hard to determine accurately.

What Are Hypergiants And Supergiants?

These are two terms about stars that we will encounter in our study. Hence, it makes sense to understand what they mean and what visual picture we can conjure when we hear these words.


Hypergiants and supergiants are highly luminous stars in the universe. Hypergiants are normally larger than supergiants and have more mass. There may be yellow hypergiants, red supergiants, blue supergiants, and so on.

Hypergiants are very rare and have a high mass, size, and luminosity. They are unstable and keep losing mass owing to high stellar winds. What makes these stars interesting to study is their star formation, stability, and ability to provide astronomers with the evolution of stars.

Which Stars Are The Biggest Ones In Our Universe?

This list may be subjective, as different people claim that different stars are the biggest in the universe. Nevertheless, this list comprises the biggest stars that are much bigger than other stars in the sky.

The biggest stars known to astronomers to date include:

V838 Monocerotis

This is a red star that belongs to the Monoceros constellation. It is around 19,900 light-years away from the Earth and was discovered after a notably massive eruption in 2002.

Following the outburst, it was one of the largest known stars for a short period. It is one of the world’s biggest stars owing to its solar radii range of around 380 to 1,970.


Belonging to the constellation Orion, this star has a solar radius about a thousand times brighter than the Sun. It is visible from October to March and is close to 640 light-years away from the Earth.

Don’t believe it? Its range is between 950 to 1,200 solar radii and there are chances of it turning into a supernova. What makes this star unique is both its size as well as its brightness.

How big and bright is it? It is notably:

  • The tenth brightest star in the entire universe
  • Visible on Earth through our naked eyes as one of the biggest stars
  • Orion’s second brightest star

UY Scuti

This star is another red hypergiant that was first discovered in 1860. It has a very high mass, size, and luminosity. Furthermore, it has almost 1,700 times the solar radius of the Sun.

It is around 9,500 light years away from the Earth and is about 47% cooler than the Sun. Lying near the core of the Milky Way, this hypergiant is easily one of the biggest stars in the whole universe.

VY Canis Majoris

This star is massive and luminous, but it used to be one of the biggest stars in the galaxy just a few years back. Now, it continues to be a red hypergiant that is a part of the Canis Major constellation.

It is 3,900 light years away from the Earth and is known to keep changing frequently. Even its solar radius varies often and is about 1,420 on average.

KW Sagittarii

This red supergiant is also known as KW Sgr. It is located in the Milky Way within the boundary of the Sagittarius constellation. It is approximately 7,800 light years away from the Earth and has a 0 Kelvin temperature.

It isn’t rare for stars to have such temperatures, but this continues to be one of the most important aspects of this star. KW Sagittarii is roughly 1,480 times the radius of the Sun. Using a powerful telescope, we can find it past the orbit of Jupiter.

V766 Centauri Aa

We might have heard of Alpha Centauri and Beta Centauri. This star is located just outside of Centaurus. It is slightly Southwest of Beta Centauri and is about 21% cooler than the Sun. This hypergiant is yellow and has a varying magnitude of 6.17 to 7.50.

This tends to keep changing every 495 days. When compared to the Sun, this star has a mass of 13.0 solar masses.

RW Cephei

The third largest star in the universe is the RW Cephei which belongs to the Cepheus constellation. It is an orange hypergiant that has a solar radius of 1,535 and is 11,400 light years away from the Earth.

To make it more palatable regarding how big this star is, we can replace it instead of the Sun. In this case, it would stretch beyond the orbit of Jupiter. This is how big the star is compared to the Sun.


This star is the second largest star most prominently in the universe. It has solar radii of 1,540 to 1,730 and is 163,000 light-years away from the Earth. It is a red supergiant that is located in a satellite galaxy of the Milky Way called the Larg Magellanic Cloud.

It is believed that this star was even bigger in 2004 when it was around 3,000 solar radii. Its brightness keeps fluctuating owing to the star’s light getting obscured by the presence of torus-shaped clouds of dust.

What Other Big Stars Exist In The Universe?

These are just a few of the biggest stars in the universe that have interesting points of study surrounding them. Owing to a lack of accuracy while determining the sizes of big stars, the list is subjective.


Nevertheless, some of the other stars that are of massive sizes in the universe include:

  • KY Cygni
  • AH Scorpii
  • PZ Cassiopeiae
  • Westerlund 1-26
  • HD 143183

Be informed that this list of big stars can keep changing at any time. They tend to erupt and shed their masses which calls for frequent recalculation of their solar radii. This is why astronomers are so fascinated when it comes to stars. They indicate a lot about stellar evolution and provide a lot of scope for future study.

It is also worth noting that there might be even bigger stars than those that are hidden in the universe. This is due to dust and other particles present in the Solar System that hides them from astronomers.

Frequently Asked Questions

Which Star Is The Biggest In The Universe?

UY Scuti is notably one of the biggest stars in the universe owing to its solar radius which is 1,700 times more than that of the Sun. It is almost 9,500 light-years away from the Earth with very high luminosity and mass.

What Are Big Stars Generally Called?

The biggest stars are often called the red giants. This is because of the helium that sinks to the star’s core and increases its temperature. The outer shell of hot gases they possess expands and can even lead to the star’s demise. Nevertheless, many stars are cooler than the Sun.

How Do You Classify A Star As A Big One?

Depending upon the radius of the star and its mass, we can determine if the star is a big one or just another one among the millions of stars in the universe. The sizes of stars are compared to the size of the Sun and how much temperature or mass they possess.

Summing Up

Stars are massive luminous celestial objects and determining which ones are the biggest is often a difficult task. Nevertheless, some stars in the universe are massive and indubitably larger than the rest.

It is difficult for scientists to confirm the exact size of stars. It is also unknown if there are more big stars in the universe that are yet to be found. They may be hidden by dust and irregular gases. After all, stars are made of hydrogen and helium, which themselves are gases.


The biggest stars of today may crash and turn to dust. A small star may gain high solar radii and become a red hypergiant. The possibilities are endless and unpredictable even for the most knowledgeable scientists.

Hence, our best bet is to keep staying star struck and keep researching to find out more about our universe.

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