Latest articles by Charles Q. Choi
Why does hair turn gray?
Hair grays because pigment-producing cells get stuck within the hair follicle, research suggests.
Why do cats knead?
If a cat kneads on your lap, it's likely because it feels safe around you. But why do they knead in the first place?
New York City may be sinking under its own weight because the buildings are too heavy, scientists warn
Scientists estimate the mass of the 1,084,954 buildings within the five boroughs of New York City is 1.68 trillion pounds.
Modern humans arose after 2 distinct groups in Africa mated over tens of thousands of years
Modern humans may descend from two or more genetically distinct streams that split but continued to occasionally mix over time in Africa.
Some of the 1st ice age humans who ventured into Americas came from China, DNA study suggests
The first wave of humans into the Americas during the last ice age may have hailed partly from northern China, according to a DNA study of ancient and modern Indigenous people.
Modern humans migrated into Europe in 3 waves, 'ambitious and provocative' new study suggests
Modern humans migrated into Europe in three waves: 54,000, 45,000 and 42,000 years ago, a new study claims.
1st mega-tsunami on record since antiquity was triggered by Tonga volcanic eruption
The eruption was the most powerful natural explosion in over a century, triggering a tsunami hundreds of feet high.
Will Earth ever lose its moon?
The moon is slowly creeping away from Earth, but will we actually lose the moon before the sun turns into a red giant and destroys us both?
Why don't hurricanes form at the equator?
Here's why hurricanes, also known as tropical cyclones and typhoons, don't form at the equator and why it would be rare for them to cross it.
Why do dogs tilt their heads?
Dogs commonly tilt their heads, but is it a sign of intelligence, or does it mean something else entirely?
How deep is the Mariana Trench?
The bottom of the Mariana Trench is about 35,876 feet (10,935 meters) deep, making it deeper than Mount Everest is tall.
How many hearts does an octopus have?
Octopuses are odd: They have more than one heart and copper-rich blue blood.
Unknown lineage of ice age Europeans discovered in genetic study
The largest study yet to look at the genetics of ice age hunter-gatherers in Europe has uncovered a previously unknown lineage dubbed the Fournol.
Insect that flings pee with a butt catapult is 1st known example of 'superpropulsion' in nature
Glassy-winged sharpshooters rapidly fire their pee out of butt catapults.
Bering Land Bridge was only passable during 2 brief windows, study finds
The first people to enter the Americas may have taken the coastal route along the Bering Strait Land Bridge during these two periods.
Massive, 1.2 million-year-old tool workshop in Ethiopia made by 'clever' group of unknown human relatives
An unknown group of hominins crafted more than 500 obsidian hand axes more than 1.2 million years ago in what is now Ethiopia.
Prehistoric population once lived in Siberia, but mysteriously vanished, genetic study finds
A genetic study has revealed the existence of a previously unknown hunter-gatherer group that lived in Siberia upwards of 10,000 years ago.
How many times can you fold a piece of paper in half?
It's easy to fold a piece of paper in half once, twice or even three or four times. But what's the highest number of times one piece of paper can be folded in half?
How long do dogs live?
The average life expectancy of a dog is more than 10 years, but life span varies greatly among different breeds.
What is the largest squid in the world?
There are two contenders for the world's largest squid, and both are giants.
Who was the world's first author?
The oldest known writing dates back more than 5,000 years. But who was the first author we know by name?
Why does chocolate turn white (and is it safe to eat)?
Sometimes dark or milk chocolate gets a white sheen or blotchy white spots on it. What is happening, and is chocolate that has turned white safe to eat?
