Moon and Antares

The Moon huddles close to the heart of the scorpion this evening – the star Antares. It’s among the 15 brightest star systems in the night sky. If our eyes could see all forms of light, Antares would look perhaps 10 times brighter still. That’s because it emits most of its energy in the infrared – wavelengths that are too long for the human eye to perceive. All stars emit radiation across the electromagnetic spectrum – from radio waves to X-rays. That includes the Sun. But the mix of wavelengths depends on the star’s surface temperature, which we see as its color. Stars like the Sun are yellow-white. Their energy peaks at visible wavelengths – the type of energy our eyes have evolved to see. Stars that are hotter than the Sun look white or blue. But their light peaks beyond those colors – mainly in the ultraviolet – wavelengths that are much too short for us to see. Antares, on the other hand, is thousands of degrees cooler than the Sun, so it looks orange. But it emits most of its light in the infrared. And it produces a lot of it. The star is a supergiant – far bigger than the Sun. At visible wavelengths, it shines about 10,000 times brighter than the Sun. Throw in the infrared and all the other wavelengths, and it could be a hundred thousand times the Sun’s total brightness – one of the true stunners in our part of the galaxy. Tomorrow: A planetary Big Bad Wolf. Script by Damond Benningfield