Every so often I like to go into more detail about the life and times of those twinkling stars we see night after night in the Butler sky when clouds aren’t photo bombing our night skies. All of the stars we gaze on are going through different stages of life. It’s not like the carbon-based life we thrive on, but stars are born, live, and die. The common thread to all three stages is gravity. When it comes to astronomy, you can almost say that gravity is everything. This week I want to take you to the maternity ward of stellar birth.

Since stars, including our sun, are basically huge balls of mainly hydrogen gas, it only makes sense that stars are born out of loose clouds of hydrogen. As it turns out, there are gigantic hydrogen gas clouds, trillions of miles in diameter, all around our home Milky Way Galaxy and the billions and billions of other galaxies that make up our known universe. These nebulae are the birthplace of hundreds and thousands of stars, many of which are born at nearly the same time in these giant stellar nurseries.

There’s a great example of stellar birth in the winter night sky, and it's the Orion Nebula in the constellation Orion. Just below the three bright stars in a row that outline the hunter's belt, there are three that are fainter in a shorter row that depict Orion's sword.

Even to the naked eye, the middle star of the sword seems fuzzy. That's because it’s not a star but a vast cloud of hydrogen gas over 80 trillion miles in diameter and more than 1,400 light-years away, with just one light-year equaling nearly six trillion miles.

So how do these gigantic gas clouds, otherwise known as nebula, become the birthplace of stars? Here’s what happens. The gravitational influence from a passing star or group of stars, or the shock waves from an old exploding star in the distance, stirs up the nebulae. As this happens, random pockets of denser gas begin developing within the nebulae, and stellar birth gets cooking. Since these denser balls of hydrogen are more massive than the surrounding looser nebulae, they start acquiring a gravitational force that draws in more and more of the surrounding hydrogen. As this happens, these protostars become even more massive, giving them a stronger gravitational pull that allows them to pull in more and more of the surrounding gas.

Like a snowball rolling down a hill, these balls of hydrogen gas grow and grow like crazy until they become massive enough to become stars. They get “lit up” and start shining like stars when their nuclear fusion furnaces ignite deep in their interiors. That can’t happen until the giant hydrogen gas ball becomes so massive that its own gravitational force squeezes so hard, causing tremendous pressure to build up in the center of the protostar. We’re talking to the tune of billions of pounds per square inch! Just like a giant pressure cooker, this drives the temperature up millions of degrees inside the core. When a critical level of heat is built up in the center of the protostar, the nuclear fusion furnace gets kicked in, and the star begins its life of shining.

If you look at the center of the Orion Nebula with even a small telescope or good pair of binoculars, you'll see a tiny trapezoid of four stars born by going through this same process. These stars are incredibly young, way less than a million years old. That's like a newborn human baby only a few minutes old in the lifespan of stars. The surrounding hydrogen gas in the nebula is lit up like a fluorescent light by the tremendous radiation pouring out of these baby stars. If you don’t want to wait until this coming late fall or early autumn to check out the Orion Nebula, the Lagoon Nebula in the constellation Sagittarius the Archer rises in the southeast after 11 pm.

Next week in Starwatch I’ll have more on the inner workings of stars. The dynamics are mind-blowing and controlled mainly by gravity

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.