The next transit of Mercury will not be until 2032.
Venus's surface is an inhospitable wasteland. But its upper atmosphere is much like Earth.
Full alignment will be easier to see from the Southern Hemisphere—but people at Northern latitudes should still be able to spot Mars, Saturn and Jupiter.
Binoculars or a telescope might be necessary to see some of the planets.
The moon will come within four-moon diameters of Saturn in the night sky.
Around dusk tonight, Castor and Pollux will form a nearly straight line with Venus.
"It's just completely bizarre that we should have two planets the same size but opposite ends of the habitability spectrum."
Are we really alone?
Here's what we know—and don't know—about our neighboring planet.
The moon won't obscure three planets again in this way until 2036.
Hidden volcanoes and greenhouse gases mean if you were standing on the Venusian surface it would be like swimming 1,000 metres below sea level—if the ocean was scorching hot.
Mercury, Venus, Saturn, Mars and Jupiter will be visible in the pre-sunrise sky for the next month.
The bright celestial bodies appeared side by side as they reached a "conjunction" point Tuesday night.
The two brightest celestial bodies, after the sun and the moon, will appear side by side in this month's sky.
Fireballs can be as bright as the sun and larger than a full moon