How Many Earths Can Fit In the Sun? The Answer Will Blow Your Mind

The Sun is a star that resides at the center of our solar system. This spherical ball of hot gas and plasma converts hydrogen into helium via nuclear fusion. It creates 4 million tons of energy every second, which it emits as light and radiation throughout the solar system. This energy eventually makes its way to Earth and serves as the most important energy source that allows life to flourish on Earth. Although it appears small from a distance, the Sun dwarfs the Earth in terms of size. That said, exactly how large is the Sun, and how many Earths can fit inside it? Let’s take a closer look at the Sun and learn about its formation, structure, and size. 

5 Amazing Facts About the Sun

• While temperatures at the surface of the Sun average around 10,000 degrees Fahrenheit, temperatures at the core can exceed 27 million degrees Fahrenheit. 
• The Sun is sometimes known as a “yellow dwarf,” although it actually radiates white light and is a medium-sized star. 
• It takes approximately 27 Earth days for the Sun to rotate on its axis.  
• The Sun is part of Population I, a generation of young, metal-rich stars commonly found in the arms of the Milky Way galaxy. 
• Sunspots represent dark, cooler patches on the Sun’s photosphere that form when magnetic field concentrations within the Sun rise to the surface. 

Size of the Sun

By far, the Sun is the largest object in the solar system. In fact, its mass constitutes over 99% of the mass in the entire solar system. In terms of shape, the Sun almost appears as a perfect sphere. It has a total radius of around 435,000 miles, meaning its diameter measures around 864,000 miles. Meanwhile, the Sun’s circumference measures around 2,715,000 miles. The total volume of the Sun equals around 1.4 x 10^27 cubic meters, while its mass equals approximately 1.9 x 10^30 kilograms. That said, the sun’s weight and size constantly change over time. Solar winds carry particles away from the sun every second, causing it to lose tons of energy in the process. Still, experts estimate that the Sun has only lost about 0.05 percent of its mass over the last 4.6 billion years. 

Despite its massive size, the Sun only classifies as a medium-sized star. Although it measures 90% larger than the other stars in the Milky Way galaxy, many stars in the observable universe measure significantly larger than our own Sun. Billions of stars measure tens or hundreds of times larger than the Sun. The largest known star in the universe, UY Scuti, has a radius nearly 1,700 times larger than the Sun. This means that nearly 5 billion suns could fit inside of UY Scuti. 

How Many Earths Can Fit Inside the Sun?

From our limited perspective, the Earth appears absolutely massive, while the Sun looks small and distant. However, this perspective could not lie further from the truth. In reality, the Sun measures substantially larger than the Earth by many magnitudes. Unlike the Sun, the Earth is not a perfect sphere. Our rotation causes the planet to bulge slightly along the equator, leading to different radii measurements from the equator and the poles. The radius of the Earth at the equator equals 3,963 miles, while the polar radius equals 3,950 miles, for a total difference of 13 miles. Given these measurements, the Earth’s equatorial circumference equals around 24,901 miles, while its meridional (pole to pole) circumference equals around 24,860 miles. It has a mass of about 5.9 x 1024 kilograms and a volume of around 260 billion cubic miles. 

Upon comparing the Earth’s dimensions to the Sun’s, you can quickly see how drastically they differ. Put simply, the mass of the Sun measures approximately 333,000 times greater than the mass of the Earth. In terms of volume, it would take around 1.3 million Earths to fill up the Sun. Talk about a lot of Earths!

Formation of the Sun

The Sun is approximately 4.6 billion years old. Back then, our solar system consisted of a giant, rotating cloud of dust and gas known as a solar nebula. Over time, the gravity generated by the nebula caused it to collapse in on itself. This made the nebula spin faster and gradually flatten into a disk as it pulled material in the space around it toward its center. Over 99.8% of the mass in the entire system gravitated toward the center, leaving the remaining mass on the fringes. This left-over mess eventually formed into the planets of our solar system that currently orbit the Sun.

What is the Sun Made Of?

The vast majority of the Sun consists of two elements, hydrogen, and helium. Hydrogen makes up approximately 75% of the sun’s composition, while helium makes up just under 24%. The last 1% or so consists of substances known as “metals.” In astronomical terms, “metals” refers to heavier elements such as carbon, oxygen, iron, and neon. 

Like the Earth, the Sun has several regions or zones. The inner region consists of the core, radiative zone, and convection zone. Temperatures in the core can reach 27 million degrees Fahrenheit, and the density is 150 times greater than the density of water. Meanwhile, the radiative zone constitutes the thickest layer of the Sun or about 0.45 solar radii. In the radiative layer, the transfer of energy made in the core is done via radiation, hence its name. A thin layer known as the tachocline separates the radiative zone from the convective zone. In the convective zone, convective currents move the Sun’s energy out toward the surface.        

Past the convective zone lies the Sun’s atmosphere, which consists of the photosphere, chromosphere, transition zones, corona, and heliosphere. The photosphere is the visible surface of the Sun. Photons created in the photosphere escape through the Sun’s atmosphere and turn into visible solar radiation, known as sunlight. Meanwhile, the transition zone emits most of its light as ultraviolet rays and is heated by the super-hot corona above it. Matter blown off the corona turns into solar winds that create a huge magnetic field around the Sun. This field is known as the heliosphere and encompasses all the planets in the solar system. That means that the Earth and all the planets technically lie within the Sun’s atmosphere!

How Far Away Is the Sun from Earth?

The Earth and Sun are both constantly in motion. Moreover, the Earth does not orbit the Sun in a perfect circle. Rather, the Earth’s orbit looks more like an oval, known in astronomical terms as an ellipse. As a result, the distance from the Sun to the Earth changes depending on the time of year. In early January, the Earth reaches its closest point to the Sun, known as perihelion. At this point, the Sun is about 91.4 million miles away. Six months later, the Earth arrives at its furthest point from the Sun, known as the aphelion. At that moment, the Sun is about 94.5 million miles away. This means that the Earth’s average distance from the Sun equals approximately 93 million miles. Astronomers refer to this distance as 1 astronomical unit. This simplification makes it easier for scientists to develop working models of the solar system. 

The photo featured at the top of this post is © Aphelleon/Shutterstock.com