What If Earth Was Bigger Than The Sun?

What If Earth Was Bigger than the Sun?

As the biggest thing in the solar system, everything revolves around the Sun. And who knows where Earth would be if it didn’t have the raging ball of fire nearby? Our solar centerpiece towers over its neighbors, but what if another rose to take its place?

This is Unveiled, and today we’re answering the extraordinary question; What if Earth was bigger than the sun?

So, how big is our home planet right now? And how does it compare to the sun? Ranking as the fifth largest planet in the solar system, Earth boasts a 25,000 mile circumference and a diameter of just over 7,900 miles. Not bad, but those figures pale into insignificance alongside our central star which has a circumference stretching for well over 2.5 million miles - and a diameter of more than 850,000 miles. All in all, the Sun occupies such an enormous volume of space that it could carry approximately 1.3 million Earths.

So, Earth ever being bigger than the sun is clearly impossible. But, in a hypothetical scenario in which it was, there are two ways it could play out; either Earth ‘outgrows’ the sun, or the star undergoes an unexpected case of shrinkage and becomes smaller than our planet. Either way, the fundamental make-up of the solar system changes and humanity is in for a rough time.

The first option sees Earth increase to 1.3 million-times its current size to match the Sun. Assuming its general mass increases at the same rate, the planet's gravitational pull would also drastically grow to be vastly more powerful than our current version. If this expansion were to happen suddenly, everything on the planet's surface would be crushed to dust.

Very quickly, unless the moon also receives an equivalent upgrade which would see it grow to be bigger than Jupiter, our natural satellite wouldn’t be able to resist Earth's new gravitational force. And so, it would plummet to the planet's surface, causing yet more destruction.

Further afield, the Earth would now wield a gravitational pull on the Sun itself, as well. If Earth only slightly outgrew the sun, as the distance between the Earth and the Sun’s cores would remain the same, the two objects could even begin to orbit each other, entering into an effective stalemate since neither one holds enough influence to force the other into submission - like two colossal, cosmic boxers circling each other but the punch never arrives.

On the other hand, if the two bodies were to somehow swap sizes, so the Earth is as big as the sun now and vice versa, the star would eventually orbit around the planet. Although, at this point, the Earth could no longer be described as “a planet”. According to the International Astronomical Union, a planet - in the solar system, at least - has to tick a few boxes; mainly, it has to hold the required self-gravity to sustain a spherical shape and must also orbit around the sun without succumbing to any debris scattered along the way. This definition isn’t without its detractors, but even counter-arguments – usually pertaining to Pluto – would struggle to cater for our scenario.

So, if Earth would no longer qualify as a planet, then what would it be? Well, it would almost certainly have to be a star. Unlike planets, stars are capable of producing their own light; a phenomenon that’s mostly dependent on mass and energy. If an object meets the necessary size, its core becomes hot enough to cause hydrogen atoms to fuse into helium. As a specific example of why size matters; despite consisting of the same gases as the Sun, Jupiter is nowhere near large enough to make the grade as a star.

Perhaps unsurprisingly, any super-sized-earth-transforming-into-a-star scenario leaves zero room for humankind. The sheer heat generated from such an expansion would cause our planet’s rocky composition to break down into gas, and we’d definitely be doomed. But, could the same be said about the entire solar system?

If Earth (or, indeed, anything else) were to transform into a star and form a Binary system with the current Sun, our solar system would actually be behaving more typically. Because, in other systems, it’s actually more common to find two (or more) stars orbiting around an established center of mass rather than one flying solo. Our solar system runs so smoothly thanks to every mass primarily being influenced by one dominant gravitational pull. For example, the moon is primarily affected by the Earth, while Earth is primarily affected by the Sun. The solar system is, in effect, perfectly balanced to maintain equilibrium.

But, back to our hypothetical Sun-Earth binary star system… and compared to some other systems the two dominant forces would be relatively far away from each other - which is bad news for all the other planets.

Rather than revolving around a solitary mass, planets would fall under the influence of two. The outer most planets might be able to survive by skirting the Binary Stars as though they were a single entity, but the likes of Mercury, Venus and Mars in particular would increasingly become unstable, caught in a kind of cross-system crossfire. Because of their closer proximity to Earth, Mars and Venus could naturally drift towards the new star causing impossible-to-predict changes to their atmospheres and fundamental makeups. The layout of the solar system would just be completely different, and though there could well remain a ‘goldilocks’ zone where life could exist, there’d be no real indicators of where that zone would be, and whether any planet could still occupy it.

So, what if Earth was bigger than the sun in the other way? In that, the sun shrunk - in terms of size, mass and every measurement - to be smaller than the Earth is now? Well, the effects of this second scenario are much easier to predict - but, as you may’ve guessed, the results wouldn’t be pretty. Once again, humanity is doomed, but this development brings untold, horrendous consequences for the entire solar system - mainly, that it would no longer exist. This (theoretically impossible) super-small sun couldn’t provide the energy to power even the planets closest to it, while it’s gravitational influence would disappear as well. Earth, Mars and everything else would turn into dead, frozen balls of ice, cast off into outer space, destined to travel the universe for eternity or until they crash into (or are caught up in) another star system. It’d be the end of days for our particular corner of the Milky Way.

Thankfully, these situations are very much hypothetical scenarios. But, that’s what would happen if the Earth was bigger than the Sun.