# How big is the largest star in the universe?

The diameter of the earth is about 1.28 kilometers and the mass is about 60 trillion tons. By human standards, the earth is already very huge, and the sun is extremely huge. The volume of the sun is about 1.3 million times that of the earth, and the mass is 330,000 times that of the earth. From the mass point of view, the mass of the sun accounts for 99.8% of the total mass of the solar system.

In fact, looking at the entire universe, the mass of the sun in the universe is at a low-medium position, and its volume is still very small compared to the largest star in the universe, and a planet as huge as the earth is just a dust in the vast universe. . How big is the largest star in the universe?

# The largest star

The largest known star in the universe is called UY Scuti. Its size is so huge that the sun appears insignificant in front of it.

UY Scutum is a red supergiant star about 9,500 light years away from Earth. According to scientists’ calculations, the diameter of UY Scutum reaches 2.38 billion kilometers, while the diameter of the sun is only 1.392 million kilometers. The diameter of UY Scutum is 1708 times that of the sun. In terms of volume, UY Scutum is 5 billion times the sun and 650 billion times the earth.

Maybe many people have no idea about this data. Let’s put it this way, the average distance between the sun and the earth is 150 million kilometers, which is only 1/16 of the diameter of UY Scutum. If the sun in the center of the solar system is replaced by UY Scuti, the edge of UY Scuti will be close to the orbit of Saturn (Saturn is 1.4 billion kilometers away from the sun), and the earth will be swallowed mercilessly from Jupiter.

If you fly at the speed of light and circle the equator of UY Scutum, then you will need 6.9 hours, and circle the sun’s equator at the speed of light in just 14.6 seconds. It will take more than 10 years to fly around the UY Scutum equator with the fastest aircraft launched by mankind so far.

Because of its huge size, although its mass is not the largest known in the universe, it is also relatively large, about 7-10 times the mass of the sun. Due to its huge mass, the nuclear fusion reaction on UY Scutum is very intense, so its life span is relatively short. It is estimated that its life span is only tens of millions of years, while the sun’s life span is as high as 10 billion years.

# The most massive star

The largest star in the universe known to man is R136a1, which is a blue supergiant star. It is estimated that the mass of R136a1 is at least 265 times that of the sun.

R136a1 is located in the Large Magellanic Cloud, approximately 165,000 light-years away from Earth. Due to its huge mass, R136a1 is very bright. If R136a1 is placed in the solar system, its brightness relative to the sun is equivalent to the sun relative to the moon. Although the mass of R136a1 is very large, due to its high density, its diameter is much smaller than UY Scutum, only 29 to 35 times the diameter of the sun, but it is also approaching Mercury’s orbit.

And R136a1, like UY Scutum, has a very short life span, less than 10 million years. At the end of their lives, they will end their lives in the form of supernova explosions, each becoming a black hole.