StarDate

Robert McCall was not only inspired by spaceflight, he helped inspire others to achieve it. He produced magazine illustrations, murals, postage stamps, and other artwork about space, both real and imagined.

McCall was born 100 years ago today, in Columbus, Ohio. During World War II he wanted to be a pilot. But he was colorblind, so the Army made him a bombardier instead.

After the war, he produced artwork for several magazines. And in the early 1960s, he illustrated articles on the space program for Life magazine. That led to an invitation from NASA to join its art program. He was given inside access to the early space missions.

Many of his works were realistic depictions of those missions. Others were realistic depictions of imaginary missions — to the Moon, Mars, and beyond.

McCall produced murals for the National Air and Space Museum, Johnson Space Center, and others. He designed crew patches for the final flight to the Moon and other NASA missions. And he did a score of stamps with space themes.

McCall also worked on films. He created promotional artwork for “2001: A Space Odyssey,” and concept art for “The Black Hole” and the first Star Trek movie.

McCall died in 2010. But his work is in view in museums, art galleries, web sites, and elsewhere — perhaps inspiring future scientists and engineers to reach for the stars.

Script by Damond Benningfield

Orion strides across the southern sky this evening. The hunter climbs into good view in the east and southeast shortly after nightfall. His brightest star, Rigel, stands to the right of his three-star belt.

If the hunter ever gets tired during his never-ending journey across the sky, he can always prop his feet up for a little rest. That’s because a “footstool” has been provided for him in the adjoining constellation Eridanus, the river. The stool is marked by the moderately bright star Cursa. Its name comes from an Arabic phrase that means “the footstool.”

For the most part, Cursa is unremarkable. It’s a few times bigger and heavier than the Sun, and a few dozen times brighter. It’s used up the original hydrogen fuel in its core, so it’s undergoing a series of changes. The changes will cause its core to get smaller and hotter, igniting the next round of nuclear fusion. As that happens, its outer layers will get bigger and cooler. That will make Cursa shine much brighter than it does now. It’ll also give the star a definite orange hue.

One remarkable thing did happen to the star more than three decades ago. For a couple of hours, it flared to more than 10 times its normal brightness. But it hasn’t repeated the flare-up, so astronomers can’t explain the footstool’s brief showiness.

Cursa stands just above Orion’s foot — bright blue-white Rigel — in early evening, ready to give the hunter a break in his journey across the night sky.

Script by Damond Benningfield

It’s likely to be many years before people land on Mars — and decades before they begin to settle there. Yet engineers and artists are already pondering what living on the Red Planet might be like. They’ve come up with ideas for habitats, rovers, space suits, and many other components of everyday life.

Many of those ideas have come together in “Moving to Mars,” an exhibition in London. It includes concepts developed for NASA and the European Space Agency as they plan early human missions.

As part of a NASA competition, one design firm came up with a concept for a habitat that makes use of Martian dirt. Robotic machines would land on Mars and use the dirt to construct a shield against radiation from the Sun. Later, modules shipped from Earth would be inflated below the shield. The modules would include living quarters, labs, and workshops.

Other designers have looked at ways to reduce the amount of material that has to be shipped from Earth, such as making clothing from used parachutes.

By the time anyone heads toward Mars, of course, technology will have changed. So few of today’s designs are likely to be selected for the trip. Yet they may spur more ideas as we get closer to the first journeys — making it possible to live on Mars.

And Mars is in good view the next couple of mornings. It looks like a modest orange star, low in the southeast at first light. It stands below the Moon tomorrow, and to the upper right of the Moon on Monday.

Script by Damond Benningfield

The Sun is making itself scarce as seen from the northern hemisphere right now. That’s because tomorrow night marks the winter solstice, so the next couple of days are the shortest of the year — the days with the shortest interval between sunrise and sunset.

Astronomically, the solstice marks the beginning of winter. The Sun stands farthest south in the sky, so the southern hemisphere receives most of the Sun’s energy, leaving the north dark and cold.

Perhaps a bit surprisingly, though, the solstice isn’t the coldest time of year. If you look at the average temperatures here in the United States, you’ll find that the weather is coldest anywhere from a few days to a couple of months after the solstice. The lag tends to be greater from northern latitudes than southern ones.

The effect is called the seasonal lag. And there are a couple of reasons for it. For one thing, the Sun stays low in the south for a good while after the solstice, so its rays come in at a low angle. That’s the least efficient angle for heating things up — they get warmer much faster when the Sun is higher in the sky.

The most important reason for the lag, though, is that it takes the land and oceans a long time to begin warming up — especially the oceans. It’s not until well after the solstice that they absorb enough energy to start warming up — and to start heating the air as well — building toward their peak well after the summer solstice in June.

Script by Damond Benningfield

In the final day of its life, the core of a massive star is a busy factory. It churns out new chemical elements at an incredible rate. And when that day ends, the star explodes. That scatters some of the newly formed elements into space, where they might someday be incorporated into new stars and planets.

All stars create energy by “fusing” lighter elements to make heavier ones. Stars that are at least eight times the mass of the Sun produce a larger variety of elements.

Near the end of that process, a layer around the star’s core has been converted to silicon. Over the final day, the silicon stages complicated reactions that produce sulfur, calcium, titanium, iron, and others.

Most of those elements take part in the nuclear reactions. But not iron. It takes more energy than the star can produce for the iron to fuse together to make still-heavier elements. So the star stops producing energy. Its core collapses, and its outer layers are blasted into space. For a brief time, the explosion produces enough energy to make even more elements.

Such stars are the source of the iron, silicon, and many other elements found here on Earth — elements forged in the stars.

One star that’ll be making those elements appears near the Moon the next couple of mornings. Spica will stand below the Moon tomorrow, and to the right of the Moon the next day. Spica is massive enough to end its life as a supernova — and spew a bounty of elements into the universe.

Script by Damond Benningfield

One of the brighter stars in Cepheus, the king, is between 850 and 900 light-years from Earth. Knowing that range is especially important because the star is like a mile-marker. Its distance helps astronomers measure the scale of the entire universe.

Delta Cephei is high in the northern sky as night falls. It’s above the figure of Cepheus, which looks like a child’s drawing of a house.

Delta Cephei is at the end of its “normal” lifetime, so it’s going through some changes. They make the star unstable, so it pulses in and out like a beating heart. Each “beat” takes more than five days. And during that time, Delta Cephei gets noticeably brighter and fainter.

So do many other stars — Delta Ceph is the prototype of an entire class of stars, called Cepheid variables. And in 1908, Henrietta Swan Leavitt found that the longer it took for such a star to “pulse,” the brighter the star was.

By measuring the distances to a few of these stars, astronomers could then determine the true brightness of any of them. So by measuring how bright a Cepheid looks, they can calculate its distance. And Cepheids are bright, so they’re visible even in nearby galaxies. That allows astronomers to measure how far away those galaxies are.

And that acts as a calibration for ways to measure the distances to galaxies that are even farther — all the way to the edge of the visible universe. That’s all made possible by a few stellar mile markers — like Delta Cephei.

Script by Damond Benningfield

The final installment in the nine-movie “Star Wars” saga is set to open in theaters this week. Reports say the budget for production, marketing, and distribution will top 300 million dollars. And the movie is almost certain to rake in more than a billion dollars at the box office.

That’s about what it cost to build, launch, and operate the most recent American mission to Mars. InSight is designed to learn more about the planet’s interior by listening for marsquakes, and by measuring temperatures — which it’s had some trouble with.

Over the last few years, the price of a blockbuster movie has been creeping closer to the cost of sending a spacecraft to Mars or the Moon. A 2016 European Mars lander, for example, cost about the same as the 2012 movie “John Carter,” which was set on Mars. Both of them failed. And a companion orbiter cost about as much as “The Last Jedi.”

And when you consider the amount of money many films earn at the box office, the comparisons are even more staggering. The $630 million brought in worldwide by “The Martian” could just about have covered the entire budget of MAVEN, a Mars orbiter.

Smaller spacecraft and commercial competition could reduce the costs of missions in the years ahead. And better technology should make it possible to provide better views from solar system explorers. So someday, a high-def livestream from the surface of Mars itself might cost less than a fictional view in a theater.

Script by Damond Benningfield

Here on Earth, the poles are a lot colder than the equator — by a couple of hundred degrees. And it’s the same for most of the other planets. That’s because the Sun shines more directly on the equator than the poles, pumping in more energy.

But for some stars, it’s just the opposite: the poles are much hotter than the equator.

A prime example is Regulus, the bright star that marks the heart of the constellation Leo, the lion. It’s close to the right of the Moon as they climb into good view late this evening.

What we see as Regulus is one of four stars that make up the system. The others are so faint, or so close to the bright star, Regulus A, that they’re invisible without some help.

The poles of Regulus A are almost 10,000 degrees hotter than its equator. And that’s because of the star’s high-speed rotation.

Regulus A spins at about 700,000 miles per hour at the equator — hundreds of times faster than the Sun spins. The fast rotation pushes gas at the equator outward, so Regulus is about a third wider through the equator than through the poles.

That puts the poles much closer to the star’s core, which is where it generates energy. Because of that, the poles are hotter than the equator. And that makes them brighter than the equator, too. So if we could see Regulus A from close range, it would look a little like a lozenge that’s bright at the top and bottom, and much fainter around the middle.

Tomorrow: fact and fiction in the stars.

Script by Damond Benningfield

The bright yellow-orange star Capella stands about a quarter of the way up the northeastern sky at nightfall. It’s the leading light of Auriga the charioteer. Capella links with the constellation’s other major stars to form a hexagon, which spreads out below and to the right of Capella at that hour.

Several star clusters reside in or near the hexagon. These are families of scores to hundreds of stars. Each family is bound together by the stars’ mutual gravitational pull.

The best-known clusters are Messier 36, 37, and 38. They’re easy targets for binoculars.

M37 is the brightest of the three, even though it’s about 4500 light-years from Earth. It stands a little below the hexagon. The cluster contains more than 500 stars, all of which may be up to 500 million years old. M36 contains about half as many stars, and is only about 25 million years old. And M38 is smaller still, and about halfway between the ages of the other two.

Over the eons, all three clusters will lose some of their stars. Those at the edges of a cluster are more loosely bound than the ones near the center. The gravitational “fingers” of the rest of the galaxy’s stars and gas clouds eventually will drag the stars away. In fact, it’s possible that one or more of the clusters could completely disintegrate. All of their stars would then go their separate ways — leaving their stellar homes for the wide-open spaces of the galaxy.

Script by Damond Benningfield

Exactly 10 years after its launch, a small space telescope has discovered stars and galaxies galore — not to mention asteroids, star clusters, and many other intriguing objects.

WISE — the Wide-field Infrared Survey Explorer — was designed to look at the sky in wavelengths that are blocked by Earth’s atmosphere. Those wavelengths reveal details about how stars are born, how galaxies evolve and merge, and much more. And they reveal especially cool objects such as asteroids and the “failed stars” known as brown dwarfs.

By the end of its first year in orbit, WISE had scanned the entire sky twice. It cataloged about 750 million infrared objects. By then, it had used up the ice that kept its instruments cold. So the spacecraft was placed in hibernation.

Some of its instruments could still work without being super-cold. So WISE was revived to pursue a new mission: hunting and tracking N-E-Os — Near-Earth Objects. These are asteroids and comets that come close to Earth’s orbit, making them potential threats to our planet.

That mission — known as NEO-WISE — continues today. So far, it’s yielded more than a hundred new NEOs. And it’s produced images of hundreds of previously known ones. The images help reveal the sizes of these objects — details that tell us how much of a threat these space rocks might present.

Script by Damond Benningfield