Look Up! The Valentine's Day Star Is High in the Sky Tonight

ESA/Herschel/PACS/L. Decin et al.
ESA/Herschel/PACS/L. Decin et al. / ESA/Herschel/PACS/L. Decin et al.

At 8 p.m. EST on Valentine's Day, take the one you love outside and look up at the sky. At that time every year, the brightest red star in the sky will reach its highest point. For that reason, it is sometimes called the Valentine's Day Star. It was given its nickname by astronomer Jack Horkheimer, who said that "if you want to give your beloved a really big Valentine, well this is about as big a one as you'll ever find." The valentine even "pulses" over the years as its atmosphere expands and contracts.


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Formally, the star is called Betelgeuse (pronounced like the Michael Keaton character). It is a red supergiant—one of two such stars easily recognized in an evening sky. (The other red supergiant is called Antares.) Betelgeuse is located 640 light-years from Earth. (One light-year is about 6 trillion miles.) The star is really big. If we swapped it for our own Sun, it would burn through the four terrestrial planets of our solar system, and the asteroid belt. Jupiter would likely have a bad time of it as well.

Fans of the Hitchhikers Guide to the Galaxy novels will recognize the star for its association with Ford Prefect, who was born on a planet somewhere in its vicinity. In nonfiction, Betelgeuse has no known planets—the star is only 10 million years old, after all, which is hardly enough time to develop a planetary system. For comparison, our Sun is 4.57 billion years old—an age Betelgeuse will never reach. Scientists know it will explode, but there are different estimates on when that will happen. Some say 100,000 years from now, others say 1 million. 


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Betelgeuse is visible now, so before you drag your love into the cold winter's air for a Valentine's evening of stargazing, it might not be a bad idea to practice finding it first. The good news is that you almost certainly know where it is and have probably seen it before. Betelgeuse is in the constellation Orion's right shoulder. The easiest way to find Orion is to look for his belt: the bright stars Alnitak, Alnilam, and Mintaka. Mentally orient the belt horizontally, and you'll find his head straight up from there (where heads tend to be in relation to belts), and his shoulders are about where you would expect. Betelgeuse is the red one.

Orion was a mighty hunter in Greek mythology. Because he vowed to kill all of the animals of the Earth, Gaia ("Mother Earth") sent a scorpion to kill him. In the story's telling, this is why the constellations Orion and Scorpio are never seen in the night sky at the same time. The gods placed the two in the stars so that one would rise as the other sets. The most notable star in Scorpio? Antares, the other red supergiant.