Every time Venus passes the Earth, it shows the same face. This remarkable fact has been known for only about 50 years, ever since radio telescopes have been able to […]

Humanity is under attack. The attack is not from large tentacle-flailing aliens, but from invaders so small they can barely be seen, and so strange they are not even clearly […]

The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible near the image center, at least two long funnel-shaped clouds, each roughly half a light-year long, […]

It was bright and green and stretched across the sky. This striking aurora display was captured in 2016 just outside of Östersund, Sweden. Six photographic fields were merged to create […]

Follow a sunset on a clear day against a distant horizon and you might glimpse green just as the Sun disappears from view. The green flash is caused by refraction […]

That’s not a bright star and crescent Moon caught between branches of a eucalyptus tree. It’s Venus in a crescent phase and Mercury. Near the western horizon after sunset, the […]

Still bathed in sunlight, the International Space Station arced through the evening sky over lake Wulfsahl-Gusborn in northern Germany, just after sunset on March 25. The familiar constellation of Orion […]

What are those dots between Saturn’s rings? Our Earth and Moon. Just over three years ago, because the Sun was temporarily blocked by the body of Saturn, the robotic Cassini […]

What’s higher than the Himalayas? Although the Himalayan Mountains are the tallest on planet Earth, they don’t measure up to the Milky Way. Visible above the snow-capped mountains in the […]

Inside the head of this interstellar monster is a star that is slowly destroying it. The huge monster, actually an inanimate series of pillars of gas and dust, measures light […]