But as the telomere vanishes, our chromosomes fray, and cells can no longer replicate to replace old or damaged ones. This is how we age.
Check out some of the coolest discoveries of the last year:
Best Discoveries of 2015
Science suggests having more children helps mothers stay young
Miners in Botswana discovered the second-largest gem-quality diamond ever found. The stone is the biggest diamond to be discovered in more than a century. Clocking in at 1,111 carats, it's a size that makes Kim Kardashian's 15-carat ring look like a dinky toy you win out of a vending machine.
Swiss cheese is one of the easier kinds to identify, thanks to it being riddled with holes. What has remained harder to pin down, however, is how the spaces end up there in the first place. After about a century of research, scientists have finally figured out what causes them. It's hay.
Researchers say they've discovered the first known fully warm-blooded fish. It's called the opah, or moonfish, and it lives in cold environments deep below the ocean's surface. Scientists say the opah generates heat by constantly flapping its pectoral fins.
Stonehenge's origin has been a mystery for centuries, but archaeologists now believe it was actually a "second-hand monument." An earlier version might have been erected in Wales.
Read more here.
A new scientific report suggests that the plague has been infecting humans for about twice as long as previously thought.
Read more here.
British scientists using forensic anthropology, similar to how police solve crimes, have stitched together what they say is probably most accurate image of Jesus Christ's real face, and he's not the light-skinned figure many of us are used to seeing.
Egypt's Ministry of Antiquities has announced that, based on the group's infrared thermography survey, the northern wall seems to register different temperatures. This could indicate that there is a secret chamber on the other side.
In images released by NASA's New Horizons spacecraft, dwarf planet Pluto features breathtaking views of icy mountains, streams of frozen nitrogen and haunting low-lying hazes that hint at the weather changing from day to day on Pluto, just like it does here on Earth.
A new study reveals the mechanisms behind the below-surface ocean phenomenon known as internal waves which can reach more than 600 feet high and travel for more than a thousand miles before breaking under water.
Archaeologists have uncovered human remains of four of the earliest leaders of the English colony that would become America, buried for more than 400 years near the altar of what was America's first Protestant church in Jamestown, Virginia.
According to a recent study, some common household sounds have been shown to trigger seizures in certain cats.The top noise culprits included a metal spoon hitting a ceramic bowl, the tap of a glass, the rustling of a paper or plastic bag, the click of a keyboard or mouse, and the jangle of keys or coins.
Dogs are called 'man's best friend' - women's, too - and scientists say the bond between people and their pooches may be deeper than you might think.
Researchers said oxytocin, a hormone that among other things helps reinforce bonds between parents and their babies, increases in humans and their dogs when they interact, particularly when looking into one another's eyes.
Researchers think they've found an inner-inner core. Iron at the Earth's core forms into crystals. The scientists found within the inner core, there's another region where the crystals don't line up with the rest of the inner core.
The discovery could shed light not only on how exactly the Earth's core works but also on how the core and the Earth itself developed billions of years ago.
The water below the Antarctic ice sheet is as cold and dark as ever, but it turns out it's not as desolate as scientists thought. Researchers recently discovered that there's a whole ecosystem down there, complete with fish, crustaceans, and various invertebrates.
The researchers say one outside explanation for the findings could be that having more children led to more help from the community in child rearing, which freed up energy in the body to maintain cells.
You can read the study in full in the journal PLOS One.