StarDate

Two constellations that are entwined in both mythology and the sky climb into good view in the east and southeast this month.

Ophiuchus, the serpent bearer, is one of the larger of the 88 modern-day constellations. Its brightest stars form a pattern that looks a bit like the outline of an old coffee urn. It’s flanked by the two halves of Serpens, the serpent. The snake’s head rises above the serpent bearer, with its tail below.

In mythology, Ophiuchus was associated with Asclepius, the son of the god Apollo. He became a great healer, in part because of an encounter with a snake. One day, he saw a snake resurrect another one by laying some herbs on top of it. Asclepius began using those same herbs. He not only healed the sick, but he managed to raise the dead as well.

That was bad for the business of Hades, the god of the underworld. He complained to Zeus, the king of the gods. Zeus killed Asclepius with a lightning bolt. But according to one version of the story, that set off a tiff between Zeus and Apollo. To end it, Zeus moved Asclepius into the stars — as the serpent bearer.

To find the serpent bearer and the serpent, look low in the sky as night falls for two prominent stars: Altair, which is due east, and Antares, in the southeast. Ophiuchus and Serpens spread far above these bright stars.

We’ll have more about Ophiuchus tomorrow.
 

Script by Damond Benningfield

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60 years ago today, the Soviet Union astonished the world:

RADIO MOSCOW: This is Radio Moscow. For the first time in history, a woman has gone up into outer space. A Soviet citizen, Tereshkova.

Valentina Tereshkova was a 26-year-old textile worker. She was picked by Soviet Premier Nikita Khruschev, who was a master of space propaganda. It was the height of the Cold War, and space travel was a powerful symbol of national power. Every space flight was held up as an indicator of a superior way of life.

Only a few astronauts and cosmonauts had left Earth by then — all of them men. Sending a woman into orbit was designed to show that the Soviet space program was more advanced than the American one.

Khruschev himself selected Tereshkova to fly solo aboard the Vostok 6 capsule. Another cosmonaut was already in orbit, aboard Vostok 5. The two craft briefly passed within three miles of each other. That was trumpeted as a major accomplishment as well.

Tereshkova spent three days in space, during which she talked to Khruschev by radio. After returning to Earth, she was awarded the Order of Lenin and became a goodwill ambassador.

Tereshkova later was elected to the Russian parliament. But she never flew in space again. Neither did any other woman for almost 20 years. Today, more than 70 women have entered orbit. And female astronauts are training for trips to the Moon — extending the path laid by Valentina Tereshkova.
 

Script by Damond Benningfield

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You might think that asteroids are a dime a dozen. After all, astronomers have discovered more than one-and-a-quarter million of them. Most are in the asteroid belt — a wide band between Mars and Jupiter. But more than 30,000 pass close to Earth.

Yet that dime-a-dozen valuation is way off. Many asteroids contain vast amounts of metals. That makes them potential gold mines — not to mention mines of iron, nickel, cobalt, silver, platinum, and other elements.

The Near-Earth asteroids might someday be mined for those metals. They could provide resources for solar-system exploration at a lower cost than bringing them up from Earth.

A study a couple of years ago, for example, estimated the value of the asteroid 1986DA. It’s about a mile and a half wide, and 85 percent of it could be metals. It comes close to Earth, making it fairly easy to reach. And the bounty might be worth the effort. The study estimated its value at almost 12 trillion dollars — about half the annual American economy.

Bigger asteroids farther from Earth could be worth even more. NASA is scheduled to launch a mission to the metal-rich asteroid 16 Psyche later this year. The asteroid is near the outer edge of the asteroid belt, and is about 140 miles in diameter. That places its value at perhaps 10 billion trillion dollars — a one followed by 19 zeroes — a fortune awaiting future miners in the asteroid belt.
 

Script by Damond Benningfield

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A space rock the size of a small boulder exploded above New Mexico 25 years ago this week. Fragments of the boulder, known as meteorites, rained across 10 square miles of east-central New Mexico, near the town of Portales. Local residents, scientists, and meteorite hunters combed the countryside for weeks. They found hundreds of pieces, ranging from tiny pebbles to a chunk a little bigger than a softball.

Many of the fragments wound up in museums and labs. But quite a few stayed in private hands. Today, they’re some of the most valuable rocks on the planet. In 2022, the Christie’s auction house sold the largest piece of the Portales meteorite, which weighed about 11 pounds, for more than $50,000.

Other meteorites can be even more valuable. The Christie’s auction fetched a total of more than four million dollars for meteorites. That included the single most expensive one yet sold — 722,000 dollars for an 18-pound slice of a meteorite from China. And fragments that weigh as little as a few grams can sell for tens of thousands of dollars — several times the value of gold.

Meteorites that were observed during their fall to Earth, such as the Portales fragments, are worth more than those that were picked up at random. And the most valuable of all are pieces of the Moon and Mars — rare and expensive rocks from beyond Earth.

More tomorrow.
 

Script by Damond Benningfield

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Nelda Wallace was drinking coffee on her porch in Portales, New Mexico, when an unexpected visitor dropped in: a 37-pound space rock. It half buried in the dry soil about 75 feet away, and was so hot that she couldn’t pick it up.

About the same time, another Portales resident, Gale Newberry, walked into his barn, where he found a big hole in the roof and a one-pound rock embedded in the wall.

Both rocks were part of a larger space rock that exploded high in the sky 25 years ago today. Since then, residents, scientists, and meteorite hunters have found hundreds of bits of the original rock, totaling more than 150 pounds.

The excitement began about 7:30 a.m. A rancher in nearby Happy, Texas, heard a double sonic boom and several loud pops. He also saw a bright trail across the sky, which lasted only a few seconds. After the original rock exploded, fragments pelted 10 square miles of east-central New Mexico, centered on Portales.

The original rock was part of an even bigger space rock. It came from the asteroid belt, between the orbits of Mars and Jupiter. Collisions with other asteroids melted bits of iron and nickel, which then flowed into cracks in the rock. Later, another collision blasted the Portales meteorite into space. Eventually, its orbit overlapped Earth’s, and it plunged into our planet’s atmosphere. The extreme pressure caused it to explode — raining shrapnel across the dry New Mexico landscape.
 

Script by Damond Benningfield

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Stars produce their own “acne” — blemishes on the surface. It’s more common on young stars than old ones. In fact, astronomers can use the blemishes to help determine a star’s age.

The blemishes are called starspots. They’re magnetic storms that can span thousands or hundreds of thousands of miles. They’re up to a few thousand degrees cooler than the rest of the star, which makes them darker.

The Sun produces these storms as well — sunspots. On average, they cover only about three-hundredths of a percent of the surface of the Sun. But spots can mark much more of the surface of a young star — a quarter, a third, or more. That can make the star’s overall brightness dip by a small but measurable amount.

The difference is a result of the star’s age. When a star is born, it spins fast — in a few days or even hours. That generates a powerful magnetic field. And it’s the magnetic field that creates the starspots. Lines of magnetic force get tangled and twisted. Where those lines penetrate the surface of the star, they create spots. And when the lines snap, they can create outbursts that are thousands of times stronger than any we’ve seen from the Sun.

As a star ages, though, it slows down. Its magnetic “dynamo” gets weaker, so the number of spots goes down. So astronomers can get a pretty good idea of a star’s age by combining its rotation rate with the number of spots — the common “blemishes” of youth.
 

Script by Damond Benningfield

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Venus is moving past a “beehive” of stars over the next few nights. The “evening star” will pass as close as about half a degree from the hive’s outskirts.

The beehive is the star cluster Messier 44, in Cancer, the crab. When viewed through a telescope, it looks like a swarm of angry bees.

So far, astronomers have identified about a thousand stellar bees in the hive. Two-thirds of them are red dwarfs — the smallest, coolest, and faintest class of stars. About a third are similar to the Sun. And a few are either giants or the “corpses” known as white dwarfs.

The giants are among the most massive stars in the cluster. Heavier stars burn through their nuclear fuel more quickly than lighter stars do. When it’s all gone, the star puffs up — it becomes a giant. The corpses began as even more-massive stars. They used up their fuel, became giants, then shed their outer layers, leaving only their hot but dead cores.

So the mass of a giant reveals how long it’s been around. And that can tell us the minimum age of a cluster — the cluster can’t be any younger than those stars. Using this and other techniques, most estimates put the age of the beehive at a little more than 600 million years.

The beehive stands to the upper left of Venus tonight, and a little closer to the planet over the next couple of nights. You need binoculars to see it, though — a hive of fairly young stars buzzing near the evening star.
 

Script by Damond Benningfield

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When we look into the sky, we see one big, blinding star — the Sun. All the other stars are mere pinpoints of light; the brightest star in the night sky looks less than a hundred-billionth as bright as the Sun.

But the residents of many other star systems would have two or more bright stars to look at it. That’s because most of the stars in the galaxy are members of systems with two stars, three stars, or even more.

An example is Dubhe, which marks the lip of the Big Dipper’s bowl. The dipper is high in the northwest at nightfall, with Dubhe at the bottom, as though pouring the dipper’s contents onto the ground.

Dubhe actually consists of two pairs of stars.

The brighter pair is quite impressive. One of its members is a giant. The star is nearing the end of its life, so changes in its core have caused its outer layers to puff up. The star is almost 20 times wider than the Sun, and hundreds of times brighter. Its bloated surface is fairly cool, so it glows orange.

The star’s companion is no slouch, either. It’s still in the prime of life, just as the Sun is. But it’s more massive than the Sun, so it shines brighter. And its surface is much hotter than the Sun’s, so it shines pure white.

The stars are a couple of billion miles apart — more than 20 times the distance from Earth to the Sun. Even so, if a planet orbits either star, both stars would appear blindingly bright — two “suns” for the price of one.
 

Script by Damond Benningfield

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Hermann Oberth is one of the fathers of rocketry. He inspired some of the most successful rocket designers and builders of the 20th century. Yet his “offspring” — his pioneering ideas about rockets — almost weren’t born. He first wrote those ideas in 1922, in his PhD thesis at the University of Heidelberg in Germany. His professors rejected it. “Too farfetched,” they said.

Yet Oberth’s conclusions were correct — and he knew it. So he published them at his own expense. His book, “The Rocket in Interplanetary Space,” was released 100 years ago this month.

In it, he concluded that rockets using liquid fuels would be much more efficient than those using solid fuels. No one had yet built such a rocket, and wouldn’t for a few more years. Oberth also concluded that rockets could escape Earth’s gravity, and that humans could safely go along for the ride. He even came up with the idea of multiple stages — a design that’s used in most modern-day boosters.

Oberth’s 92-page book caught the eye of several young rocketeers in Germany, who formed a famous rocket club. One of their leaders was Wernher von Braun, who would develop the V-2 terror weapon for Germany, and the Saturn 5 Moon rocket for the United States.

Oberth continued to develop his ideas, and published an extended version of his book in 1929. It offered a lot more detail on how to get into space — ideas that weren’t so “farfetched” after all.
 

Script by Damond Benningfield

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A big impact basin gives one of the moons of Saturn a dual personality. From some angles, it makes Mimas look like a giant eyeball. But from others, it gives the moon a more sinister look — like a Star Wars “death star.” And for scientists, the basin is a tool for understanding the structure and history of this intriguing moon.

Mimas is the smallest and closest of Saturn’s major moons. It’s about 250 miles in diameter, and it’s about half as far from Saturn as our moon is from Earth. It may be only a billion years old — less than a quarter of the age of Saturn itself.

The impact basin is called Herschel. It’s about 80 miles across and six miles deep. It was gouged by an impact so powerful that it almost blasted Mimas to bits.

Mimas is made mainly of frozen water, with only a smattering of rock. But there are some oddities in the way it twists back and forth. They suggest that an ocean of liquid water could be buried about 15 or 20 miles below the surface. And according to a recent study, the idea is supported by Herschel’s contours.

The ocean would have been buried much deeper when Herschel was created. Since then, the little moon’s icy crust has gotten thinner — although scientists can’t yet explain why.

Saturn appears near our Moon in the wee hours of tomorrow morning. It stands to the upper left of the Moon at first light, and looks like a bright star.
 

Script by Damond Benningfield

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