Pluto is smaller than our Moon, but it's the biggest known dwarf planet. On the inner edge of the Kuiper Belt, the Sun is so far away it would look like a bright star from there. And Pluto can get so cold that its atmosphere freezes and falls to the ground.
Where do comets come from? The Oort Cloud is home to a trillion comets at the edge of the Solar System, nearly half way to the next star. Sometimes they get kicked out and sometimes they come to visit the inner Solar System.
The Solar System's large moons tend towards the weird and wonderful, and Triton is no exception. It has ice volcanoes, a strange “cantaloupe terrain”, and crazy seasons. It's the only large moon to orbit in the wrong direction, so it didn't form near Neptune. But where did it come from?
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.”
Some people think that Venus could be habitable. And perhaps you might daydream about being closer to the Sun when the long winter nights come, and the temperature drops. After all, "Earth's twin" should be a nice place, shouldn't it? Let's talk about that.
Easter Island and a distant dwarf planet – what do they have in common? The answer is Makemake – the creator god in the Rapa Nui mythology of Easter Island. How did his name come to be given to a small frozen body seven billion kilometers (four billion miles) from the Sun?
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?