A mismatched pair of planets huddles close together the next few mornings. One of them is brilliant but small; the other is faint but giant.
Venus and Uranus are low in the east at dawn. Venus is the “morning star” — the brightest object in the night sky other than the Moon — so you can’t miss it. Tomorrow, Uranus is less than two degrees to its upper left — about the width of your finger held at arm’s length. But Uranus is so faint that you need binoculars to pick it out. It looks like a faint star.
The difference in brightness is mainly the result of the different distances of the two planets. Uranus is more than 15 times farther from Earth right now. It’s also 25 times farther from the Sun, so it receives a lot less sunlight. Yet Uranus is more than four times wider than Venus. So if you lined them up side by side, Uranus would far outshine Venus.
Seen through a telescope, Uranus looks blue green. That’s the result of methane in its upper atmosphere. It absorbs red light, allowing only bluer wavelengths to reflect out into space. Hazes of methane and other compounds also block the view of cloud features in the atmosphere, so Uranus generally looks like a smooth, bland marble.
Venus and Uranus will be about the same distance apart on Sunday morning. After that, though, the gap between them will get bigger, as Venus slides to the lower left — leaving its giant but faint companion behind.