Spica (labeled in green), Mars (labeled in red), and the crescent moon nestled in Virgo low in the Pittsburgh sky.
Credit: Kayla Waugaman Carnegie Science Center

July 29, 2025

On the evening of July 30, one of the bluest stars in the sky will gleam just above the waxing crescent moon. Spica is a blue giant star and the brightest in the constellation Virgo. Virgo, known as the “Maiden of the Harvest,” was well known to farmers. The brilliant star, Spica, represents a sheaf of wheat held by the maiden, and its Northern Hemisphere rising marked the beginning of the planting season.

Blue stars have the highest temperatures. They burn bright and fast. Between the high temperatures and high luminosity, they blast enormous amounts of energy into space and burn through their fuel faster than stars like our sun. In fact, they are the shortest-lived stars. As stars go through life cycles, their appearance changes over a time frame too large for us to notice. Most of the stars we see are in what’s called the “main sequence,” part of their lives, and become blue giants as they scorch through their hydrogen. Because blue stars burn out quickly, they are rare among stars; yet, they appear common due to their incandescent light, which draws our attention. Regulus in the springtime constellation, Leo, and Rigel, gracing the wintertime constellation, Orion, are well-known blue-giant stars.

In Antarctica, on July 30, the moon will briefly cover sparkling Spica. In Pittsburgh, the pair will shine beautifully close together.

Are you as fascinated by the night sky as we are?

Join us for SkyWatch: Carnegie Science Center’s monthly opportunity to catch a glimpse of the stars with professional telescopes. Get a great view of the Pittsburgh skyline as you stargaze with other space enthusiasts. Plus, watch a feature show at the Buhl Planetarium and participate in fun, astronomy-themed activities.