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Help astronomers look for Planet 9

There might be an unknown 9th planet that orbits far from Earth, on the outer fringes of our solar system. You can help astronomers find it, if it exists!

Today in science: John Glenn

On February 20, 1962, John Glenn became the 1st American to orbit Earth and the first American space hero.

Do animals dream?

Your dog or cat might look as if it’s dreaming when its whiskers twitch and legs wiggle. But are animals really dreaming?

What is radiocarbon dating?

At a very steady rate, unstable carbon-14 gradually decays to carbon-12. The ratio of these carbon isotopes reveals the ages of some of Earth’s oldest inhabitants.

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Star brightness versus star luminosity

Some extremely large and hot stars blaze away with the luminosity of a million suns! But other stars look bright only because they’re near Earth.

Last quarter moon is February 18

A last quarter moon rises around midnight. It appears half illuminated from Earth. The exact last quarter phase will come on February 18, 2017 at 19:33 UTC.

Watch SpaceX Dragon launch February 18

SpaceX is scheduled to launch its Dragon spacecraft resupply mission to the International Space Station no earlier than 10:01 a.m. EST (1501 UTC) on Saturday, February 18. How to watch.

Gemini? Here’s your contellation

How to see the constellation Gemini in the night sky, plus some of ancient lore about the legendary Twins.

Star of the week: Castor

Castor is one of 2 bright stars in the constellation Gemini the Twins. It appears as a single star, but it’s actually a multiple star system.

Toxic pollutants persist in deepest ocean

Banned chemicals from the 1970s have been discovered in the bodies of crustaceans in the deepest of Earth’s ocean trenches.

Where’s the moon? Waning gibbous

Watch for the moon late at night now, or before dawn. Last quarter moon will come on February 18.

Compare sizes of sun and stars

It’s hard to comprehend the sheer size of objects in space, but take 2 minutes and give it a try!

What causes the aurora borealis?

The aurora borealis, or northern lights, are an ethereal display of colored lights shimmering across the night sky. What causes them?