Mysteries of the world that science has not fully solved

Science has found cures for diseases, taken humans to the Moon and even measured the age of the universe. Yet some questions in the world still have no full answer. These are not ghost stories but real scientific and historical puzzles. Here are mysteries of the world that scientists are still working on today.

1. The Indus script: writing no one can read

About 4,500 years ago, the people of the Indus Valley (Harappan) civilisation wrote in a script on seals, pots and tablets. Thousands of examples have been found, but to this day no one has been able to read the script with certainty. Most of its inscriptions are very short — on average just 4–5 signs — and no bilingual inscription has been found to help decode it, the way Egyptian writing was cracked with the "Rosetta Stone". Read more about ancient India in Amazing facts about ancient India.

2. Roopkund: the "lake of skeletons"

Hundreds of human skeletons have been found around Roopkund lake in Uttarakhand, at a height of about 5,000 metres. For a long time it was believed they were all travellers who died at the same time, perhaps in a hailstorm. But a DNA study in 2019 surprised everyone: the skeletons belong to people from different periods — some from around the 9th century and some about 1,000 years later — and they include people of Mediterranean origin. Why and how they reached such a height is still not fully clear. Read about hail in Why does hail fall.

3. The Voynich manuscript

It is a handwritten book of about 240 pages, with text in an unknown script and drawings of strange plants, stars and people. Carbon dating showed that its pages are from the early 15th century. Even great code-breakers have not been able to read it — some think it is a secret code, others an unknown language.

Did you know? "Göbekli Tepe", found in Türkiye, is more than 11,000 years old — thousands of years older than the pyramids of Egypt and Stonehenge in England. Its huge carved stone pillars were built at a time when humans had perhaps not even begun farming. That raises the question of how and why hunting people built something so large.

4. The giant statues of Easter Island

Remote Easter Island (Rapa Nui) in the Pacific has about 900 giant stone statues ("moai"), some weighing many tonnes. How they were moved long distances from the quarry without wheels or large animals was long a mystery. Some experiments showed that they could have been "walked" forward by rocking them from side to side with ropes — and the island's folk tales also speak of the statues "walking".

5. Dark matter and dark energy

Perhaps the greatest mystery is the universe itself. According to scientists, the stars, planets, gas and we ourselves together make up only about 5% of the universe. About 27% is "dark matter", which cannot be seen but holds galaxies together with its gravity, and about 68% is "dark energy", which is making the universe expand faster and faster. What these two really are, no one yet knows. Read Facts about the Milky Way.

Mystery versus superstition

Real mysteries are ones where the evidence exists but the full answer has not yet been found — like the Indus script. Scientists investigate them, use new tools and slowly get closer to an answer. By contrast, scary stories without evidence usually do not survive investigation.

More articles: Interesting facts.