What if the size of the sun was smaller than the size of the Earth?

Written By طقس العرب on 2023/10/11

This article was written originally in Arabic and is translated using a 3rd party automated service. ArabiaWeather is not responsible for any grammatical errors whatsoever.

Arabia Weather - What is the size of the Sun compared to the Earth? Imagine if you could reduce the sun to the size of a basketball. At this time, the Earth will have been reduced to the size of a sesame seed, which is how massive our star is compared to the Earth.

But what if this fireball of gas and plasma isn't the biggest thing in our solar system? Will our planet still revolve around the sun? Or will the sun revolve around the huge Earth? What will happen to our planetary neighbors? What would this imaginary solar system look like?

Imagine the sun being smaller than the Earth

Here's what would happen if the Sun were smaller than the Earth. Put our Sun next to a supergiant star, and you wouldn't even be able to see it. But compared to the Earth, the Sun is huge.

To fill the Sun to the size of the Earth, you would need the equivalent of 1.3 million Earths. It is so large that it makes up more than 99% of the mass of the entire solar system. But it looks small when we see it from Earth because it is 150 million kilometers (93 million miles) away from us.

Well, if we assume this scenario and the Sun is smaller than the Earth; Our solar system will look completely different, and the bad news is that the Earth will no longer be habitable, and the Sun will no longer be a huge star.

In this universe, size is important, as is distance. We see the Earth close enough to the sun not to freeze, as is the case with Mars, and it is also far enough to protect it from burning, as happens with the planet Venus.

We are lucky to be in the residential area of the sun; This means that the size of our planet, the size of the Sun, and the distance between them are what make the evolution of life on Earth possible here on Earth. But, what would happen if the Sun were smaller than our planet?

The mass of a star is responsible for its color and temperature

The mass of a star determines its color and temperature. Larger stars are hotter and bluish in color, while smaller stars are cooler and red. Regarding the Sun, it is a white star, not as large as a massive giant star and not as small as a red dwarf star.

You might think that by shrinking the Sun, it would turn into a smaller red dwarf star with a smaller habitable zone. But this is not the case. By definition, a star, whether a massive giant or a red star, is only a star when thermal fusion occurs in the star's core.

What is the smallest size that stars can reach?

We haven't measured many red dwarf stars yet, but the smallest star we've discovered so far has a mass ten times that of Earth. This is very close to the size theoretically necessary for the star to sustain this merger. Anything smaller than ten times the mass of Earth would not yet be a star, but would instead be the cool, dark remnants of a star.

What if we reduced the size of the sun to be smaller than the Earth?

If whatever causes the Sun to shrink to become smaller than the Earth, it will then not have enough mass to create nuclear fusion and will be completely extinguished. Our solar system would then lose its only star since the Sun is the source of gravity holding us in its orbit and all the planets including Earth would wander through space in search of another anchor. This will not be a happy ending for life on Earth.

What if we inflated the size of the Earth to be larger than the Sun?

Let's try again, and this time let's make the Earth larger than the Sun, while the size of the Sun remains the same. The Earth's weight will be at least 333,000 times greater than it is now. Imagine the gravity it would have then, your body wouldn't be able to handle the force of gravity which would be enough to crush your bones

In reality; A planet of this size would generate enough heat and pressure in its core to become a star itself.

In either case, there would be no chance for life to survive on Earth. But life could develop on other planets, or even on the moon.