Asteroid 33 Polyhymnia is so dense it may actually contain elements never before seen on Earth, according to a new study

• Scientists think an asteroid could contain previously unknown elements. 
• Asteroid 33 Polyhymnia appears to be denser than the densest element in the Periodic Table. 
• The densest naturally occurring element, Osmium, has 76 protons per atom. The asteroid could have more than double that.

An asteroid in the solar system's asteroid belt is so dense that scientists believe it could contain elements never before seen on Earth, according to a study published in The European Physical Journal Plus in September. 

All known chemical elements on Earth are documented in the Periodic Table. There are 118 elements that make up the Periodic Table, organized by their atomic number — the number of protons in the element's atomic nucleus.

Over the years, scientists have been jamming more protons into nuclei to create new elements. But how many protons you can ultimately pack into one space is a scientific mystery. Some experts argue the threshold is 164. 

For their new study, researchers from the University of Arizona, suggest that asteroid 33 Polyhymnia might contain never-before-seen material that reaches that exact threshold.

They calculated what the density of an element with a whopping atomic number of 164 would be —  generally speaking, the higher the atomic number of an element, the denser it'll be, though there are definitely exceptions.

The researchers found that the density of an element with atomic number 164 was roughly the same density as what other experts have already measured for asteroid Polyhymnia.

It "would have a density between 36.0 and 68.4 g/cm³: a range that approaches the expected value for asteroid Polyhymnia," according to a press release.

The densest element on Earth can't compare

Asteroid 33 Polyhymnia might be what's called a compact ultradense object, or CUDO. These objects are thought to have densities far greater than the density of anything on Earth and therefore contain elements scientists have yet to discover. 

For example, the densest element on Earth, Osmium, contains 76 protons packed into each atomic nucleus. If the scientists' new calculations are correct, it would mean CUDOs like asteroid Polyhymnia could be made of material that contains elements with as many as 164 protons per atomic nucleus. 

One of the study's authors, Jan Rafelski, said in the press release: "The idea that some of these might be stable enough to be obtained from within our solar system is an exciting one."