The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radiation, and is the most important source of energy for life on Earth.
It turns out that our Sun Is an average-sized star. There are bigger stars, and there are smaller stars. We have found stars that are 100 times bigger in diameter than our Sun.
To know more about the sun and stars read the article below.
What Is A Star?
Many stars can be observed by looking into the night sky. But what’s a star? A star is an astronomical body that shines due to the radiation produced internally through nuclear reactions.
They are gaseous bodies that are made predominantly of hydrogen and helium.
At the beginning of their life, stars fuse hydrogen into helium to produce energy. After the hydrogen fuel has been exhausted, more massive stars begin to fuse heavier elements.
When a star reaches the end of its life, it releases most of its mass back into the interstellar medium. This is done either through the formation of a planetary nebula or a supernova.
In this way, stars produce and distribute heavier elements such as carbon, nitrogen, and oxygen in the universe.
The Sun Is the closest star to Earth; however, many other stars are visible at night. One of the brightest stars in the night sky is Sirius, two stars in a binary system, Sirius A and Sirius B.
It appears so bright because it has a high luminosity and is relatively close to the solar system. Another star that is visible at night is Alpha Centauri. Alpha Centauri is also a multiple-star system, consisting of two Sun-like stars and a smaller, dimmer star.
Is Sun A Star?
Our Sun is a 4.5-billion-year-old star – a hot glowing ball of hydrogen and helium at the center of our solar system.
The Sun is about 93 million miles (150 million kilometers) from Earth, and without its energy, life as we know it could not exist here on our home planet.
The Sun Is the largest object in our solar system. The Sun’s volume would need 1.3 million Earth to fill it. Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in orbit around it.
Its core is the hottest part of the Sun, where temperatures top 27 million degrees Fahrenheit (15 million degrees Celsius).
The Sun’s activity, from its powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system.
NASA and other international space agencies monitor the Sun 24/7 with a fleet of spacecraft, studying everything from its atmosphere to its surface, and even peering inside the Sun using special instruments.
Sun-exploring spacecraft include Parker Solar Probe, Solar Orbiter, SOHO, ACE, IRIS, WIND, Hinode, Solar Dynamics Observatory, and STEREO.
How Big Is The Sun?
The Sun is nearly a perfect sphere. Its equatorial diameter and its polar diameter differ by only 6.2 miles (10 km).
The mean radius of the Sun is 432,450 miles (696,000 kilometers), which makes its diameter about 864,938 miles (1.392 million km). According to NASA, you could line up 109 piles of earth across the face of the sun.
The Sun’s circumference is about 2,715,396 miles (4,370,006 km).
It may be the biggest thing in this neighborhood, but the Sun is just average compared to other stars. Betelgeuse, a red giant, is about 700 times bigger than the sun and about 14,000 times brighter.
Average Size Of A Star
Average stars are also known as intermediate-mass stars. These stars have lifetimes between 50 million and 20 billion years. These stars generate energy from the fusion of hydrogen to helium, then helium to carbon.
But how big is the average star? These are defined as stars with masses between 0.5 and 8 times the Sun’s mass, known as solar masses. One solar mass is 2×1030 kg. These stars are called dwarf stars, and their life cycle has three main phases:
- Yellow dwarf
- Red Giant
- White dwarf
If the size of a star is greater than the average star size, meaning it has a mass greater than 8 M⊙, it is called a high-mass star. These stars start their life in much the same way as an average star.
However, they have much shorter lives, and when they exhaust their fuel source, they experience a supernova. These stars are either neutron stars or black holes for the most massive stars.
The Sun is considered an average star in terms of mass, size, and luminosity. As a result, other stars will often have their properties represented in terms of the Sun.
Do Stars Move?
The stars are not fixed but are constantly moving. If you factor out the daily arcing motion of the stars across the sky due to the earth’s rotation, you end up with a pattern of stars that seems never to change.
The stars seem so fixed that ancient sky-gazers mentally connected the stars into figures (constellations) that we can still make out today. But in reality, the stars are constantly moving.
They are just so far away that the naked eye cannot detect their movement. But sensitive instruments can detect their movement.
Consider driving down the highway in the mountains at 60 mph. The telephone poles on the side of the road seem to whiz past you, but the distant mountains seem to hardly move at all.
They are traveling at the same speed (60 mph) relative to you. The mountains just seem to move slower than the telephone poles because of a perspective effect known as parallax.
Here’s a fun watch on this phenomena:
In general, the more distant an object, the less it moves in your field of view for a certain, fixed actual speed. The stars (even the closest ones) are vastly farther away than the mountains, so their motion in our field of view is minuscule. But they are still moving.
Our Sun is an average-sized star: there are smaller stars and larger stars, even up to 100 times larger. Many other solar systems have multiple suns, while ours just has one. Our Sun is 864,000 miles in diameter and 10,000 degrees Fahrenheit on the surface.