Scene from a desert planet: a panoramic view of the Payson outcrop near the Opportunity rover’s landing site. With its ocean long gone, Mars may yet have liquid reservoirs underground, and spacecraft have seen signs of surface flows. Life, if it ever existed, most likely followed the water.

Would We Know Alien Life If We Saw It?

And have we already seen it on Mars?

Thomas Keilig manages SOFIA’s telescope and science instruments.

A 747 for Star-gazing

How engineers altered a jumbo jet to carry the world's biggest airborne telescope.

The powdery lunar soil was great for making footprints, but was a problem for astronauts like Charlie Duke, shown here during the Apollo 16 mission in 1972. It got in their eyes and throats, and clung stubbornly to every surface.

Stronger Than Dirt

Lunar explorers will have to battle an insidious enemy—dust.

Astronomers observed the ripples in space-time caused by gravitational waves from two black holes colliding.

When Stars Collide

Enter Einstein's grand construct of gravitational wonders, and do not attempt to adjust your television set.

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