An artist’s concept of an astronaut walking on Mars. But what would happen if the astronaut weren’t wearing a space helmet?
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Mars is the fourth planet from the Sun and one of our closest neighbors in space. But it’s not a very welcoming place for an Earthling to visit.
Don’t call them tentacles: An octopus has eight arms.
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With nine brains, blue blood and a talent for camouflage, the octopus is one of the most fascinating creatures in the sea.
A tornado in Turkey, Texas.
Jana Houser
You can’t photograph the inside of a twister, but radar offers some clues.
The depths of the valleys on a key act like a code that must match the lock.
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A computer security expert explains how keys work – and how they are like passwords.
The Earth viewed from the Apollo 8 lunar mission on Dec. 24, 1968.
NASA
The Earth is a resilient planet, but people are altering it in ways that may take centuries to reverse.
The same thing that makes their eyes glow helps cats see better in dim light.
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A veterinary ophthalmologist explains what’s going on.
Pluto, the largest of the dwarf planets. This image was taken by NASA’s New Horizons spacecraft.
NASA/JHUAPL/SwRI
The dwarf planets in our Solar System are cold, dark, far away and full of surprises.
Artist’s rendering of the Chicxulub asteroid entering Earth’s atmosphere 66 million years ago, triggering events that caused a mass extermination.
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Cockroaches have been on Earth far longer than humans and may outlast us. Here are a few reasons why.
English theatrical productions had all-male casts in the olden days.
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It may have had something to do with protecting female purity. No official statute clearly required men to do all the acting back then.
Murmurations can have as many as 750,000 birds flying in unison.
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These coordinated movements of a flock of starlings follow no plan or leader. Scientists used to think the animals must communicate via ESP to create these fast-moving blobs.
Memorial tanks at the Ukrainian Motherland Monument in Kyiv.
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Who are the Ukrainians and when were they part of the same empire as Russia? A scholar answers basic questions on war in Ukraine.
Listening to music can be a joyful experience.
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As long as you don’t tune out the world and protect your hearing, it’s hard to overdo it.
Cartilage makes this scalloped hammerhead shark’s body flexible.
NOAA NMFS
Hard and strong, or bendy and flexible? A cartilaginous skeleton provides advantages in the ocean, but wouldn’t stand up to life on land.
No matter its cause, diarrhea is uncomfortable.
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Poop comes in many shapes, sizes and textures. The kind that’s too runny might be the result of wayward germs, Crohn’s disease or lactose intolerance.
Step away from the cotton swabs!
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That brownish/yellowish gunk that comes out on your finger if you scratch deep inside your ear? It actually serves an important purpose in your body.
The body starts plugging up wounds as quickly as it can to prevent blood loss and infection.
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Blood plays a vital role in keeping us alive, from delivering oxygen to the body’s organs to fighting off infections.
Specialized anatomy means flightless penguins are master swimmers.
Christopher Michel
How did penguins end up with so few bones – and become lightning-fast swimmers?
Allium schoenoprasum , better known as chives.
Andreas Rockstein/Flickr
Plants need light to feed themselves, so they grow in ways that help them collect as much of it as they can. Sometimes that’s straight up, but not always.
Most candy is basically just a heap of sugar.
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A healthy diet can include some candy. But if you eat too much, it can interfere with your appetite for the stuff your body actually needs.
Lava flows from a fissure in the aftermath of eruptions from the Kilauea volcano on Hawaii’s Big Island, May 22, 2018.
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Volcanoes might seem like nature’s incinerators, but using them to burn up trash would be dangerous and disrespectful to indigenous people who view them as sacred.