If you’re a geology nerd, you might already know the answer to this – or, you’ll think that you do, at least.

The thing is, the universe is a big place, so you just might be wrong.

Elements have shaped every interaction in the universe, and are a consequence of how we utilize them. If you think that means there is an easy answer to this question, think again.

First, we start with weight and mass, which are two different – but linked – scientific concepts. Mass is an intrinsic property of matter, while weight is a force that depends on the surrounding gravitational field.

Mass, then, makes the most sense when trying to define the literal “heaviest.”

In many places, the answer is uranium. The isotope uranium-238 is typically considered to be the heaviest element found in the natural world. It’s atomic mass is 238 – 92 protons and 146 neutrons.

Every other element with a higher number of protons was first created in a lab. That said, plutonium (94 protons) does occur naturally, which means plutonium-244 is the answer (though extremely rare).

Scientists have created much bigger elements than plutonium, though.

Oganesson (Og) is the heaviest element every synthesized, with 118 protons and 176 neutrons (atomic mass 294).

It was discovered in 2002 and the Joint Institute for Nuclear Research (JINR).

It’s possible that the answer could be different one day. Scientists are always experimenting with stable protons and neutrons in order to get to a bigger mass element.

So, go ahead and answer this question at parties with confidence.

At least, for the foreseeable future.

If you think that’s impressive, check out this story about a “goldmine” of lithium that was found in the U.S. that could completely change the EV battery game.