The majestic constellation Orion the Hunter is a familiar celestial friend to stargazers in the Butler night sky during the winter.

I never get tired of looking at it, even in light-polluted skies. As soon as twilight fades, it dominates the southeastern sky with all of its bright stars and celestial treasures, both bright and faint. It’s not difficult to see how ancient Greeks and Romans envisioned Orion as the mighty nocturnal hermit hunter. To me, it also resembles a bow tie or an hourglass in the eastern heavens.

Orion is easy to recognize because of the three bright stars in a row that make up his belt; Alnitak, Alnilam, and Mintaka. Last week in Starwatch, I featured the great Orion Nebula, visible even to the naked eye. It’s a colossal cloud of hydrogen gas more than 1,500 light-years away, where hundreds and hundreds of young stars have and will be born.

This week I want to tell you about Orion the Hunter’s brightest stars, Rigel and Betelgeuse, anchored at opposite corners of Orion. They are the fourth- and fifth-brightest stars in our skies. Betelgeuse marks the hunter’s right armpit, and Rigel marks his left knee. Nowhere else in our night sky will you see two stars this bright so close to each other. They’re physically nowhere near each other but seem that way because both are part of the same constellation and nearly the same direction from Earth.

Being that this is Valentine’s weekend, let me start with Betelgeuse, mainly because it’s a red giant star, but there are other ties as well. Even with the naked eye, you can see Betelgeuse’s reddish hue.

Without a doubt, it’s one of the biggest single things you’ve ever seen. It’s over 20 times the mass of our sun and is estimated to have an average diameter of over 700 million miles. Astronomers have a really difficult time estimating the girth of Betelgeuse, as the gargantuan star is surrounded by a vast cocoon cloud of gas and dust.

It’s also difficult because Betelgeuse expands and contracts just like a beating heart (another nod to Valentine’s Day). When it contracts, Betelgeuse is not quite as bright in our sky. That actually happened last winter, but since then, it’s pretty much gone back to its normal brightness. Even when Betelgeuse is at its minimum diameter, our sun, Mercury, Venus, Earth, and Mars would fit inside of it!

The pulsations of Betelgeuse are a sign that it’s close to the end of its celestial life. Very large stars like Betelgeuse become very unstable as they begin to exhaust the fuel in their cores that keep nuclear energy going. Eventually, they explode in what astronomers call a supernova. No one really knows for sure when this will happen, but it may be within the next 100,000 years.

It’s a good thing that Betelgeuse is more than 500 light-years away from Earth because it could make for a really bad day here on when it does finally blow! If Betelgeuse exploded within a hundred or so light-years of Earth, the radiation from the blast could change or eliminate life as we know it on our planet. Keep your social distance from us, and then some Betelgeuse!

At the other corner of the constellation is Rigel, the brightest star in Orion, slightly outshining Betelgeuse. Rigel is a little over 850 light-years away, with one light-year equaling almost six trillion miles. Rigel is so bright in our winter sky because it’s 60 million miles in diameter and kicks out more than 80,000 times more light than our sun, making it the most luminous star in our part of the Milky Way Galaxy.

Its outer layer has an estimated temperature just under 20,000 degrees, twice as hot as our sun.

There’s a downside to big and bright stars like Rigel. They don’t live as long as smaller stars like our sun. They’re literally gas guzzlers, going through the hydrogen fuel in their cores at highly prodigious rates.

It’s hard to estimate the exact age of any star since there are so many factors to consider. Most astronomers estimate that Rigel is a little over eight million years old and doesn’t have much time left.

By comparison, our own sun sips its nuclear fuel and is about halfway through its expected lifetime of around one billion years. It’s hard to believe, but when dinosaurs roamed around our world, Rigel was not yet in our starry sky, and it will be long gone before our sun checks out.

Next week I’ll finish my little trilogy about Orion and zero in on the fantastic stars that make up the hunter’s belt.

Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Contact him at mikewlynch@comcast.net.