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Some of the brightest stars in the night sky are in view early this evening. Sirius, the brightest of all, is low in the southwest as night falls. Bright orange Betelgeuse is well to its upper right, with Aldebaran closer to the lower right of Betelgeuse.
To the eye alone, these stars look changeless. Careful observations, however, show that Sirius moves in orbit with a small, faint companion. Bubbles of gas bigger than the Sun rise and fall across the surface of Betelgeuse. And Aldebaran changes brightness as the result of changes in its core.
All of these changes can help scientists understand how stars work, and how they evolve as they age. The fullest understanding requires observations made over years, decades, or even centuries — something known as “time-domain” astronomy.
And astronomers are putting more effort into that area — preserving observations made in prior years.
Many of those observations are in the form of glass plates. They can reveal how objects have moved, how they’ve changed in brightness, or how they’ve expanded. Harvard Observatory has digitized thousands of these images, some dating back to the mid-1800s, and other observatories are preserving their plates as well.
Some observations will be tougher to preserve — those that are archived on punch cards or magnetic tape, for example. Yet these, too, can help astronomers see how the universe changes from night to night.
More about astronomy technology tomorrow.
Script by Damond Benningfield