StarDate Billy Henry

The Moon passes especially close to the star Pollux tonight — the brighter “twin” of Gemini. The star stands just to the right of the Moon at nightfall. The other twin, Castor, is farther along the same line.



The Moon always passes closer to Pollux than to Castor. That’s because of the relationships of the three bodies to the ecliptic — the Sun’s path across the sky.



The Moon’s orbit is tilted a bit with respect to the ecliptic. Over the course of a month, it meanders to either side of the ecliptic. And over a period of almost two decades, its maximum distance from the ecliptic varies as well. At most, the Moon can appear 6.6 degrees from the ecliptic — the width of three fingers held at arm’s length. So the Moon can pass close to, or even cover up, any star or planet within that distance from the ecliptic.



Pollux and Castor are outside that zone. Pollux is 6.7 degrees from the ecliptic, while Castor is about 10 degrees away. So the Moon can sometimes appear to almost touch Pollux, while always keeping a little bigger gap with Castor.



Over millennia, the ecliptic shifts with respect to the background of stars. So for thousands of years, the Moon could sometimes pass in front of Pollux, hiding it from view. That last happened about 2100 years ago. Pollux will move back into the Moon’s range in about 10,000 years — setting up some especially close encounters.



Script by Damond Benningfield

It’s hard to think of the White Sands region of New Mexico as confining. It covers thousands of square miles, and few people live there. In the late 1940s, though, the U.S. military was feeling hemmed in. It was launching rockets from White Sands. They could go high, but they couldn’t go very far without flying over towns or cities — a possible danger to residents.



So Congress passed a bill establishing the Joint Long-Range Proving Ground at Cape Canaveral, on the Atlantic coast of Florida. President Harry Truman signed it into law 75 years ago today.



“The Cape,” as it’s been known for most of those years, offered many advantages. The region had a small population, the climate wasn’t too extreme, and there were thousands and thousands of miles of ocean to plop rockets into. Launches to orbit have benefited from its southern location — rockets get a “boost” from Earth’s rotation.



It took a year to clear away some of the scrub and build the early launch pads. The U.S. Army launched its first rocket there in July of 1950 — an American-built version of the German V-2 terror weapon.



Since then, thousands of rockets have taken flight from the Cape and the facilities on nearby Merritt Island. They’ve sent satellites into orbit, astronauts to the Moon, and probes to all the planets of the solar system — and beyond. And today, the facilities are busier than ever — at the first American spaceport.



Script by Damond Benningfield

Science and science fiction can intertwine in some interesting ways. Consider krypton — the chemical element and the fictional planet.



The element was discovered in 1898. It makes up a tiny fraction of Earth’s atmosphere — about one part in a million. It’s colorless, odorless, and tasteless. And it almost never reacts with other matter. It’s used in some fluorescent light bulbs and in lasers.



In 1938, the creators of “Superman” needed a home planet for their visitor from another world. They named it Krypton, after the element, and wrote that the planet had exploded.



As scientists learned more about how elements form, they calculated that krypton must be forged in supernovas — the explosions of massive stars. The immense energy smashes together atoms to make heavier ones. The elements are fired into space, where they can be incorporated into new stars and planets. And that’s where Earth’s krypton came from. Some is in the air, but a little bit is found in the solid planet.



A few years ago, scientists studied some radioactive forms of krypton far below the surface. The krypton matched that found in meteorites. The scientists concluded that big space rocks brought not only krypton, but water, carbon, and other essential ingredients as Earth was taking shape.



So an element found on Earth and immortalized in the comics came from exploding stars — and played a role in learning about the formation of Earth.



Script by Damond Benningfield

The names of the stars that are visible in the night sky can be obscure. But that’s not the case for the star known as Elnath. The name comes from Arabic, and it means “the butting one.” That makes perfect sense when you consider that it forms the tip of one of the horns of Taurus, the bull. It’s the second brightest star in the constellation.



Elnath is quite impressive. It’s about five times the mass of the Sun, more than four times wider than the Sun, and about 700 times brighter. Its surface is much hotter than the Sun’s, so Elnath shines almost pure white. And the star is only about 100 million years old, compared to four and a half billion years for the Sun.



Look for Elnath near the crescent Moon the next couple of nights, quite low in the early evening sky. It’s above the Moon tonight, and closer to the lower right of the Moon tomorrow night.



Elnath was the favorite star name of Sandy Wood, my predecessor as the host of Star Date. After first hearing the name, she jokingly decided that she wanted to be called “the butting one,” and often signed her emails to colleagues as simply “Nath.”



Sandy passed away earlier this year. She was with Star Date for 28 years and more than 10,000 episodes. She won fans around the country and around the world. Her warmth, kindness, and giddy sense of humor were legendary. A friend and colleague perhaps described her best: She was joy in human form. Sandy Wood will be missed — and remembered.



Script by Damond Benningfield

It’s easy to see pictures in the night sky. Just pick out some stars and connect them to make a pattern. The skywatchers of ancient Babylon linked some stars to show a man pouring water from a jar. Today, that picture is known as Aquarius, the water bearer. The constellation is in the east-southeast before dawn.



Near the left side of the constellation, you’ll find a much smaller star picture: a bowling ball scattering some pins. The ball is the planet Saturn, which looks like a bright star. And the pins are represented by five stars of Aquarius. The stars are faint, so you need dark skies to see them, and binoculars will enhance the view.



The brightest of the five stars is to the upper left of Saturn by less than the width of a pencil held at arm’s length. Phi Aquarii consists of two stars. The brighter one is about as massive as the Sun, but many times larger. That’s because it’s billions of years older than the Sun, so it’s moved from the prime life into the next phase.



About the same distance to the lower right of Saturn is Chi Aquarii. It’s a giant as well, but even bigger and brighter. That makes it visible across 600 light-years of space.



Finally, three stars are a little farther along that line —Psi 1, 2, and 3 Aquarii. The brightest is number one — a triple star 150 light-years away.



Saturn will roll past the stars over the coming days — leaving some faint “bowling pins” behind.



Script by Damond Benningfield

In our region of the Milky Way Galaxy, the stars are a long way apart. The Sun’s nearest neighbor is more than four light-years away — 25 trillion miles. In the core of a globular cluster, though, the stars are packed hundreds of times more densely. That means the stars are only a few light-months apart, or even light-weeks — much closer than in our own neighborhood.



One of the most prominent globular clusters is in Hercules, the strongman. M13 — the Hercules Cluster — is perhaps 25,000 light-years away. It contains several hundred thousand stars.



M13 and the other globular clusters are thought to be the oldest inhabitants of the Milky Way. So most of the stars in the cluster are more than 10 billion years old — more than twice the age of the Sun.



Such stars are fainter, redder, and less massive than the Sun. From a planet near the cluster’s middle, you’d see a whole bunch of stars in the night sky, and almost all of them would be yellow, orange, or red — remnants of the early galaxy.



M13 is low in the northeast at nightfall. It’s along the line that connects the top two stars in the “Keystone” — a lopsided square of stars that outlines the strongman’s torso. Under clear, dark skies, the cluster looks like a dim fuzzball. It’s easier to see if you look out of the corner of your eye. It’s an easy target for binoculars — the glow of an ancient family of stars.



Script by Damond Benningfield