Grades 9-12

When Worlds Diverge

Article

When Worlds Diverge

For all their similarities, Mars possesses unique geophysical traits — traits that early on set Mars on a developmental path distinct from Earth's.

Is the Signature Still Wet?

Article

Is the Signature Still Wet?

A series of satellite photographs taken by NASA's Mars Global Surveyor, which has been mapping Mars since 1999, raise the exciting possibility that liquid water may have existed there very recently.

Article: First Planet Finishes Last

Article

Article: First Planet Finishes Last

Mercury is the most unusual of the four planets closest to the Sun. It’s also the most neglected. Until MESSENGER, it was the only one of the four that hadn’t been comprehensively imaged.

Probability and 2004 MN4: A New Drama

Article

Probability and 2004 MN4: A New Drama

In 2004, news of Asteroid MN4 hit the blogosphere: "So, in summary, there's a 1-in-233 chance of the worst disaster in recorded history happening on April 13, 2029, and a 232-in-233 chance of nothing happening." Take a closer, scientific look.

In Hot Pursuit of Asteroids

Article

In Hot Pursuit of Asteroids

Given the potential for asteroids to literally and figuratively impact life on Earth in a profound way, asteroids have been quite sought after since the first and largest one, Ceres, was discovered in 1801. Learn more.

Article: The 142-Megapixel Digital Camera

Article

Article: The 142-Megapixel Digital Camera

The Sloan Telescope has a digital camera the size of a dishwasher that’s sophisticated enough to capture every luminous object in the northern celestial hemisphere. Take a closer look.

Article: One in a Million

Article

Article: One in a Million

Have you ever stumbled upon a discovery while looking for something completely different? See what surprises astronomers found as part of the Sloan Digital Sky Survey.

Interactive

Interactive: How Far is Far?

This interactive explains how astronomers measure the properties of light from faraway space objects to calculate their distance from Earth. Users click through a series of pages that explain the concepts step-by-step with illustrations and animations.

Article: The Big Questions

Article

Article: The Big Questions

What is the Universe’s arrangement today? What did it look like at its birth? And how did we get from then to now? These are just some of the “Big Questions” astronomers are making headway answering.

The Shining Star of South African Astronomy

Science Bulletins

The Shining Star of South African Astronomy

On cloudless, moonless nights, the stars are so bright over the remote village of Sutherland, South Africa, that a person can walk by starlight alone. Learn more about the village’s Southern African Large Telescope (SALT).

Essay: The Success of Failed Stars

Essay

Essay: The Success of Failed Stars

Scientists have been studying brown dwarfs, or failed stars, for nearly a century. What have they learned? And what answers are they still seeking about these objects stuck somewhere between stars and planets?

Article: Lemurs in Madagascar—Then

Article

Article: Lemurs in Madagascar—Then

The lemurs of Madagascar, the most diverse group of primates in the world, had even more members in their ranks before humans first arrived on the island two millennia ago — 16 of the perhaps 70 species aren’t around anymore.

Shaping a Continent: Version 1.0

Article

Shaping a Continent: Version 1.0

Discover how scientists are now marrying traditional fieldwork with cutting-edge computer modeling to produce the first animated, theoretical picture of the Basin and Range Province's geological evolution.

Article: Follow the Magma

Article

Article: Follow the Magma

In 1669, the fastest and largest lava flow documented for Mount Etna on the island of Sicily killed most of Catania's 20,000 residents and destroyed much of the city. Why are scientists now watching Etna more than any other volcano in Europe? Find out.

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