A multihued aurora ripples across the night sky over Tromsø, Norway, on January 19. Auroras happen when high-energy particles from the sun slam into Earth's atmosphere, exciting gas molecules in the air and causing them to emit light. The colors seen depend on the type of molecules involved and the altitude at which the most interactions are happening. Green is the most common shade for auroras and is produced by oxygen molecules at relatively low altitudes—between 62 and 186 miles.

These Celestial Highlights Include Flowing Auroras and a Cracked Comet

Catch up on the week's best space images, from a cyclone's glowing eye to a surreal Martian vista

A closeup of a Herculaneum papyrus scroll used in an international scanning project.

Ancient Scrolls Blackened by Vesuvius Are Readable at Last

X-ray scans can just tease out letters on the warped documents from a library at Herculaneum

Ten years ago this week, the Huygens probe gave scientists a first look at the icy surface beneath the haze of Saturn's moon Titan.

Best Space Photos of the Week: From Solar Flares to Saturn's Moons

A spitting sun, a well-loved lake and a happy accident on Mars star in this week's best space images

Hubble snapped this incredibly detailed view of the "Pillars of Creation" to help mark its 25th anniversary.

Top Space Pictures of the Week, From a Hubble Icon to Hungry Black Holes

Ghostly pillars, a dark nebula and a galaxy herd starred in some of the best image-driven stories released at a recent astronomy meeting

This artist's depiction shows a gas giant planet akin to Jupiter rising over an alien ocean.

New Super-Earths Double the Number of Life-Friendly Worlds

Three studies looking at small, rocky planets are helping astronomers figure out how common worlds like ours are in the galaxy

A composite image made in Payson, Arizona, on December 28 shows Comet Lovejoy as it seemed to pass a globular cluster of stars called Messier 79.

How to See This Green Comet With the Naked Eye

The "New Year's Comet" is taking astronomers by storm with an unexpected showing, and it should only get brighter through early January

Arachnophobia, coral reefs, artificial cells and strange amphibians starred in some of this year's science finds you might have missed.

Ten Cool Science Stories You May Have Missed in 2014

ICYMI, there's a newfound coral reef in Iraq, the smallest force has been detected and more in this year's surprising science

This 1897 calendar is brought to you by parading cats.

After 12/13/14, What Are the Next Fun Dates for Math Lovers?

Sequential integers are a bit boring, anyhow. Here are some more exciting sequences to celebrate over the next 89 years

The few remaining scientists at NASA are hard at work on Earth trying to "solve gravity."

Would Astronauts Survive an Interstellar Trip Through a Wormhole?

Well, it depends on your definition of "wormhole" …

Curiosity is able to take pictures of itself on Mars using a camera mounted to its robotic arm. This mosaic was made from 55 snapshots taken in October 2012.

An Insider's Biography of a Celebrity Mars Rover

The chief engineer for Curiosity offers a peek at the NASA rover’s tumultuous rise to stardom in a new tell-all book

From left to right, panelists Eric Hollinger, Rachel Kyte, Cori Wegener and Melissa Songer discuss ideas for living in the Anthropocene.

To Live in the Anthropocene, People Need Grounded Hope

A Smithsonian symposium about human impacts on Earth looked past warnings of global doom to discuss the necessary balance of achievable solutions


See How Humans Have Reshaped the Globe With This Interactive Atlas

Zoomable maps reveal the scope of humanity’s influence on Earth—and the innovations aiming to create a more sustainable future

Pack ice and fjord walls with sedimentary strata.

Have Humans Really Created a New Geologic Age?

We are living in the Anthropocene. But no one can agree when it started or how human activity will be preserved

A shop sells nostalgic souvenirs, including a UK coat of arms, at the Portobello Road market in London.

Ten Unusual National Animals That Rival the Unicorn

Scotland doesn’t have the market cornered on exotic national symbols—check out the mouflon, the takin and the xoloitzcuintli

Figuring out the mysteries of the universe, one galaxy collision at a time.

What Is the Universe? Real Physics Has Some Mind-Bending Answers

Science says the universe could be a hologram, a computer program, a black hole or a bubble—and there are ways to check

Curtains of light weave across the sky over Fairbanks, Alaska, on September 12.

Powerful Solar Flare Paints the Sky With Candy-Colored Auroras

Two back-to-back flares sent clouds of charged particles racing toward Earth, creating auroras that may last through the weekend

A closeup of jars, probably once filled with wine, at Tel Kabri in modern-day Israel.

Huge Wine Cellar Unearthed at a Biblical-Era Palace in Israel

Residue from jars at a Canaanite palace suggest the ruler preferred his red with hints of mint, honey and juniper

Screenshot of fire burning in space.

Zero-G Fire Pulses Like a Jellyfish on the Space Station

Balls of fire burning in low gravity could help scientists create cleaner, more efficient engine fuels

The full moon is seen near Earth's horizon from the International Space Station.

Earth Is Making the Moon All Warm and Soft on the Inside

A new model boosts the notion that a layer of rock near the moon’s core is squishy and perhaps partially melted


Hear How Robin Williams Woke Up the Space Shuttle Discovery Crew in 1988

The actor and comedian provided a special message for astronauts during the first flight after the Challenger disaster

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