Mars has no little green men, but it's a fascinating place. It has a mountain three times the height of Everest and a deep valley that dwarfs the Grand Canyon. Although Mars has no liquid water on the surface, if the southern polar icecap melted, it could cover the planet 36 feet deep in water.
Earth's moon is "the Moon” because it was the only one people had ever seen until 1610. That's when Galileo discovered moons orbiting Jupiter. Why did it take until 1877 for someone to find the moons of our neighbor Mars?
The Moon has no air, no sound, no weather and no liquid water. It even has places that are colder than Pluto. But since gravity is weaker there, you could throw a ball a long way, and the footprint you left might last a hundred thousand years or more.
How does the composition of a star affect the temperature? In 1925 a young woman solved this puzzle in her doctoral thesis. Her analysis was a great breakthrough in astrophysics. Otto Struve described it as “the most brilliant Ph.D. thesis ever written in astronomy.”
The biggest, brightest nebula in our galactic neighborhood is not for arachnophobes. It's a cosmic spider hundreds of light years across known as the Tarantula Nebula. Although the nebula is 170,000 light years away it's so luminous that it can be seen with the unaided eye.
An epic tale unfolds across the sky. Woven together are its strands of seduction, hubris and divine punishment, deities and monsters, and a dashing hero to rescue a damsel in distress. Nearly thirty percent of the northern sky is dedicated to the story of Perseus and Andromeda.
The Herschel Space Observatory is the largest telescope ever sent into space. It was an infrared telescope named in honor of William Herschel who discovered infrared radiation, and his sister Caroline who worked with him. What's infrared? Who launched the telescope? What did we learn from it?
While World War I was tearing Europe apart in 1915, a German physicist presented a theory that would shake up the way we see the Universe. The physicist was Albert Einstein, his face still unknown to the world, his name not yet a synonym for genius. How did a solar eclipse in 1919 change all that?
For people living outside the tropics, June 21st is the longest or shortest day of the year, a solstice. It marks the first day of summer in the northern hemisphere and winter in the southern hemisphere. But why do we have seasons? And do other planets have them?