How to watch Venus and Mars align in a unique planetary conjunction tonight

Late last year,  Jupiter and Saturn treated skywatchers to a once-in-a-lifetime "great conjunction," when they were closer in the night sky than they had been since medieval times. And in January, our solar system's two largest planets were joined by a third — Mercury — forming a rare three-planet conjunction. 

Now, it's Earth's closest cosmic neighbors' turn. On Monday, July 12, Venus and Mars will align for their own planetary conjunction.  Our "sister planet" Venus — the planet with the closest orbit to the orbit of Earth — is sometimes referred to as the "Morning Star" or "Evening Star," based on whether it is visible around sunrise or sunset. This month, it's the latter, with the rocky, hellishly hot world appearing low in the West during the half-hour following sunset.