Cosmic Perspectives from Amid the Stars:
Astronomy Blog

Take a look into the early evening sky any night this summer, and you’ll see a bright light over the western horizon, just above where the sun set. It looks like an incredibly bright star, but it’s actually the planet Venus. Venus has often been called Earth’s sister planet. It’s a rocky planet with about the same size and mass, as well as being the closest planet to Earth, but the similarities end there. Venus is actually about as different from Earth as a rocky planet can g

Social media is buzzing with news of a so-called “planet parade” on Saturday, February 28. But before you get your hopes up, let’s separate the astronomical reality from the viral hype.

You might have heard before that the nearest star is 4.24 light-years from Earth. Or that the closest galaxy is 2.5 million light-years from the Milky Way. Or even that the most distant observed objects are 33.8 billion light-years away. But how do we measure these distances in space? After all, there’s no such thing as a cosmic ruler. That’s where the cosmic distance ladder comes in.