There's one planet in our solar system where a single day lasts longer than an entire year. Which planet is it? Mercury Venus Mars Jupiter None Deep inside two planets in our solar system, scientists believe it literally rains diamonds. Which pair of planets? Mercury and Mars Earth and Venus Uranus and Neptune Jupiter and Saturn None Astronauts returning from spacewalks say space has a distinct smell that clings to their suits. What do they most often compare it to? Fresh rain Seared steak and hot metal Pine forest Nothing β space is odorless None Mercury is the speediest planet, racing around the Sun in just 88 Earth days. So how long is a single day on Mercury, from one sunrise to the next? About 24 hours, like Earth About 10 Earth days About 176 Earth days β roughly two Mercury years Mercury has no day or night None Neutron stars are the collapsed cores of giant stars, and they're famous for being almost unbelievably dense. About how much would a single teaspoon of neutron star material weigh on Earth? About 10 pounds About a ton About a billion tons About a hundred pounds None Stumper. In 1977, NASA launched the two Voyager spacecraft, each carrying a gold-plated record meant as a message to any aliens who might find it. Which of these is actually on the Voyager Golden Record? Spoken greetings in 55 languages and a Chuck Berry song A live broadcast of the 1977 World Series The complete works of Shakespeare on microfilm A frozen sample of Earth's ocean water None Time's up