Оn the Universe scale: How many Earths can fit in the Sun?

23rd Apr 2023
Оn the Universe scale: How many Earths can fit in the Sun?

The query, “how many Earths fit in the Sun” is one of the most popular searches in Google on space topics. It may seem that the answer is not at all complicated if you apply elementary mathematical calculations. But surprisingly, opinions on this matter are divided. So, then, what is the correct answer? Let’s try to find out how many Earths could fit into the Sun!

А little bit about proportions

Did you know that the diameter of the Earth is 7,917 miles (12 741 km), and the surface area is 317 million square miles (510 162 048 square kilometres)? Seven billion people and thousands of species of flora and fauna can easily fit on Earth, and there is still a lot of free space. But on the scale of our solar system, the Earth is as tiny as a grain of sand. Judge for yourself.

Besides our Earth, there are seven more main planets in the solar system, five dwarf ones, hundreds of satellites, hundreds of thousands of asteroids and their fragments, and a myriad of space dust hovering between them. But all this makes up only 0.14% of the total mass of the solar system, while the remaining 99.86% is included into the Sun, even if it’s just a little yellow dwarf star. Still, compared to our planet, it is truly gigantic. So just how many times can the Earth fit into the Sun?

What does NASA say?

The NASA website tells us that the Sun is the largest object in our solar system. Its mass is (1.98847 ± 0.00007)⋅1030 kg, and its diameter is about 865,000 miles (1.4 million kilometres). The Sun is ten times larger than Jupiter, the largest planet in the solar system, and 109 times larger than the Earth! Does that mean that 109 Earths can fit in the Sun? Not quite.

The enormous mass allows the Sun to generate enough gravity to keep everything in orbit around it, from the largest planets to the smallest debris. To match the mass of the Sun, the Earth would have to be 330 thousand times more massive, and when the volume is concerned, it would have to be 1.3 million times larger! But does this mean that 1.3 million Earths fit in the Sun?

Can 1 000 000 Earths and more fit in the Sun?

No, they would not fit, and here’s why. Figure 1.3 million is obtained by dividing the volume of the Sun (1,412 х 1018  km3) by the volume of the Earth (1,083 х 1012 km3). Such a calculation would be reasonable if our planet somehow melted and turned into a liquid mass. But fortunately, it is still solid and, according to scientists, will remain in this state for at least another 300 million years until the Sun, gradually evolving into a red giant, burns it down. If you want to know about that, read our article How old is the Sun.

But the Earth is not only solid. Both our planet and the Sun are spheres, and it is not so easy to fill one large sphere with a mass of tiny spheres. The division of volumes would be accurate for square figures, which can be perfectly sized. But with spheres, things are somewhat different.

Check out the photo below, massively discussed on Reddit. In it, you see many small balls fit in a big one. Now imagine that each small ball is our Earth, and the big ball is the Sun.

Even the densest filling of space with balls of the same radius leaves about 26% of the larger sphere space empty. That is why the above calculation is incorrect, and so is the number 1.3 million.

So how many Earths can fit in the Sun? To get the correct answer, we must subtract 26% from 1.3 million, which will equal 962,000.

How many Earths can fit in the Sun to be exact?

Luckily for us, the exact calculation of how many Earths fit into the Sun was made by YouTuber Nick Lucid.

He ran several simulations and concluded that the total number of entire Earths that would fit inside our Sun is 932,884. At the same time, the exact loss coefficient for the empty space between the spheres in his calculation was 27.97%, and not 26% as we thought above.

 Check out this video, it is very entertaining.

1 300 000 Earths won’t fit in the Sun

As we can see, the real number of Earths in the Sun, in any case, falls really short of 1.3 million. And you can safely assert this in a dispute with any amateur space theorist.

Final thoughts

Of course, the answer to how many Earths fit in the Sun is of no practical value. The Earth is one and only, and even in the entire Universe, there are no two absolutely identical celestial bodies. But such questions always cause heated discussions, fueling public interest in space and increasing our knowledge about it. And as we all know, it is in a dispute that the truth is born.

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