StarDate

You can find Mars in many places.

In the night sky right now, it’s in the east as night falls and arcs high across the south later on. It shines like a brilliant orange star all night long.

But you can also find Mars here on Earth — or at least some reasonable facsimiles, known as analogs. Scientists have found Mars-like conditions in the Arctic and Antarctic, in the mountains of Chile and Hawaii, in a riverbed in Spain, on the glaciers of Iceland, and in several other locations.

Mars is extremely cold and dry. You can’t get all of those conditions on any one spot on Earth. But you can get some of them at different spots.

The closest Mars analog is Antarctica. It’s as cold as much of Mars, and its interior is one of the driest deserts on Earth. Psychologists have studied how people who spend the winter in bases there react to living in a Mars-like environment.

Other Mars analogs have been used to check out robotic rovers and their instruments. And still others are used to evaluate spacesuits, habitats, and other gear for human explorers.

One Mars-analog expedition has been scheduled for this week — COVID-19 permitting. Known as AMADEE, it’ll take place in a crater in the desert of Israel. It’s sponsored by the Austrian Space Forum, which has organized a dozen Mars campaigns. “Astronauts” in spacesuits will conduct experiments like those real astronauts might do on Mars itself — working on Mars without leaving Earth.

Script by Damond Benningfield

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“Polar vortex” is a phrase that’s entered the American lexicon in recent years. It’s a swirling low-pressure system centered on the winter pole. If it becomes unstable, it can sweep outward, bringing bitter misery — something that’s happened a few times here in the northern hemisphere.

Earth isn’t the only planet in the solar system with a polar vortex. Venus has double vortexes at its poles. The vortex around the north pole of Saturn forms a hexagon. And the vortex at the north pole of Jupiter is surrounded by a half-dozen other cyclones, so the whole array looks like a pan of cinnamon rolls fresh out of the oven.

The poles of Mars are encircled by vortexes as well. They’re elliptical — like squashed circles. The transition zone around them is turbulent, and plays a role in circulating dust around the planet. But the vortexes themselves seem to be pretty stable.

Studies suggest the vortexes form when carbon dioxide in the atmosphere freezes on or around the pole where it’s winter. The process pumps energy into the atmosphere, which powers the vortex. And it happens so quickly that the vortex is stable — it doesn’t have time to wobble around. That keeps the coldest air locked near the poles.

And Mars is shining at its best this month. It’s low in the east at nightfall, and looks like a bright orange star. It arcs across the south during the night, and is low in the west at first light.

We’ll have more about Mars tomorrow.

Script by Damond Benningfield

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Venus will receive a visitor tonight — a spacecraft on its way to Mercury. And a lot of folks here on Earth will be looking on.

BepiColombo was launched two years ago. Its mission is to orbit Mercury. But getting there isn’t easy. The craft needs to slow down and sculpt its path around the Sun to intersect Mercury at the right speed and time. So it will fly past Venus twice and Mercury six times, honing its orbit with each pass.

The first Venus encounter comes tonight. BepiColombo will swing just 6600 miles from the planet. And it’ll use most of its instruments to observe it. Among other things, it will measure Venus’s magnetic field and its interaction with the solar wind.

The craft also will peer into the middle layers of Venus’s blanket of clouds — something that no craft has done in decades. Something in that layer absorbs certain wavelengths of light. And some scientists have speculated that it could be microscopic life.

Another craft is orbiting Venus, so the two missions will coordinate their observations. Several observatories on Earth will be studying the planet as well. And so will quite a few amateur observers, whose work can provide a more complete picture of Venus during the encounter — a quick visit en route to another planet.

Venus is the “morning star,” so you don’t need a telescope to see it. By the time Venus rises tomorrow, BepiColombo will have left it behind — until the next encounter, in August.

Script by Damond Benningfield

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If you follow Mars across the night sky, you’ll see some odd goings-on. For one thing, it gets brighter and fainter over a period of 26 months. For another, over the same period it stops its normal motion against the sky, moves in reverse for a while, then stops and resumes its usual course. For centuries, that drove scientists loopy.

Until the mid-1500s, most thought Earth was the center of the universe. In 1543, though, Nicolaus Copernicus showed that Earth and the “planets” all orbit the Sun. That explains most of Mars’s behavior. As Earth and Mars follow their own paths around the Sun, our viewing angle changes, so Mars appears to switch directions.

Yet Copernicus assumed the orbits of the planets were perfect circles — an idea that math couldn’t confirm.

The final answer was provided by Johannes Kepler. He pored over decades of observations of Mars. After eight years of effort, he figured it out: Mars and the other planets follow elliptical orbits — like circles that have been stretched out. When it’s close to the Sun, a planet moves faster than when it’s far from the Sun. Kepler’s laws of planetary motion revealed what was happening with Mars — and all the other planets, too.

And Mars is shining at its best this week because it lines up opposite the Sun. It’s in view all night, and shines at its brightest. It’s low in the east at nightfall, and looks like a brilliant orange star.

More about Mars on Thursday.

Script by Damond Benningfield

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The night sky offers some especially beautiful sights this week. Mars is shining at its best for the entire year. And over the next couple of mornings, the crescent Moon slips past the star Regulus and the planet Venus.

Venus is the brilliant “morning star.” It’ll stand below the Moon at first light tomorrow. At the same time, Regulus — the heart of the lion — will be roughly the same distance to the upper right of the Moon.

By Wednesday morning, the Moon will have dropped past Venus. The Moon will be an even thinner crescent then. So if you look before dawn, you’ll see a brighter glow on the dark portion of the Moon, illuminated by “earthshine” — sunlight reflected from our own Earth.

Mars is in view all night. It’s at a point called opposition. That means it lines up opposite the Sun in our sky. It rises around sunset and remains in the sky all night. And it shines at its brightest — like a brilliant orange star. In fact, this month it outshines everything else in the night except the Moon and Venus.

This is an especially good opposition for Mars. The planet’s distance from the Sun varies by quite a bit. Right now, Mars is fairly close to the Sun. So as Earth moves past Mars in our smaller, faster orbit, the Red Planet is fairly close to us as well — less than 40 million miles. That’s just about as close as it ever gets, so it shines especially bright — all night long.

More about Mars tomorrow.

Script by Damond Benningfield

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Most of the stars that look like the Sun are like the Sun. In other words, stars that shine with the same yellowish color as the Sun are about the same size and mass as our home star. But a few oddballs are much bigger and heavier than the Sun, and much later in life. And two of them stand close together in the night sky. They’re the brightest stars of Aquarius, which is low in the southeast as night falls.

As seen from Earth, Alpha and Beta Aquarii aren’t all that impressive. But that’s only because the stars are more than 500 light-years away. In reality, they’re some of the brightest stars in our part of the galaxy.

Both stars are yellow supergiants. Estimates of their mass say that both stars are about five times as heavy as the Sun. And if you dropped either star in the Sun’s place, it would extend roughly to the orbit of Mercury.

The stars are only about 50 million years old — about one percent of the Sun’s age. Yet because they’re so heavy, they’re already nearing the ends of their lives. They’ve burned through the original hydrogen fuel in their cores. Now they’ve started to burn the “ashes” of those reactions. That causes their outer layers to puff up to huge proportions.

Before long — astronomically speaking — Alpha and Beta Aquarii are likely to expel those outer layers into space. That probably will leave only their hot but dead cores — a pair of white dwarfs shining feebly through the long cosmic night.

Script by Damond Benningfield

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Aquarius drifts across the southern sky on autumn nights. Tonight, it’s in the southeast as the sky gets good and dark, and due south a couple of hours later.

The constellation is known as the water-bearer. It represents a man or boy pouring water from a vase or cup.

Aquarius is one of several constellations in that region of the sky associated with water. Long ago, those constellations made key appearances during the rainy season in the Mediterranean, where the constellations were first drawn. In Egypt, for example, Aquarius heralded the annual flooding of the Nile River — an event that assured a good harvest.

It’s hard to see a water-bearer in the stars of Aquarius. In fact, it’s hard to see any pattern at all — its stars are faint and scattered.

One of its treasures is visible through good binoculars or a telescope: the Helix Nebula. It’s the final gasp of a dying star. As the star used up the nuclear fuel in its core, it blew its outer layers into space. Today, those layers span about six light-years. They’re zapped by intense radiation from the dying core, causing the nebula to glow.

The Helix is actually shaped like a barrel, and we’re looking down the center. The barrel is tilted a bit, so we see its top as one ring, and its bottom as another, shifted slightly to the side. Bright colors and intricate detail show up in images of the nebula — one of the highlights of the water-bearer.

More about Aquarius tomorrow.

Script by Damond Benningfield

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The black holes at the hearts of galaxies are described as “supermassive.” The one in the middle of the Milky Way, for example, is about four million times the mass of the Sun.

Yet “supermassive” doesn’t feel even close to adequate for describing one of the biggest black holes yet discovered. It’s roughly 34 billion times the mass of the Sun — heavier than many entire galaxies. At that mass, it would be about 20 times wider than the orbit of Neptune, the most remote major planet in the solar system.

The black hole sits at the center of a galaxy called SMSS J2157. It’s along the border between the constellations Grus and Piscis Austrinus — a point that scoots low across the south on October evenings.

The black hole is “eating” the equivalent of one Sun every day — more than any other black hole yet discovered. That surrounds the black hole with a disk of hot gas. The disk glows thousands of times brighter than the entire Milky Way Galaxy. Such bright, compact objects are known as quasars.

J2157 is so far away that we see it as it looked when the universe was less than one-tenth its current age. And that’s a problem. Current models can’t really explain how a black hole could get that big in that short a time.

So J2157 is an unexplained super-bright quasar powered by a super-supermassive black hole — a super-interesting monster near the edge of the observable universe.

Script by Damond Benningfield

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From the far-southern United States, the two brightest stars in the night sky stairstep up the south at dawn. The brighter one is Sirius, which is visible from the entire country. The other is Canopus, which is just above the horizon.

Canopus was host to the planet Arrakis in the novel Dune. Its author was born 100 years ago today, in Tacoma, Washington.

Frank Herbert was interested in books from an early age, and in science fiction. And he was a free thinker. He didn’t graduate from college, for example, because he didn’t want to take the required classes to complete a major.

Herbert spent three decades as a journalist. He published his first science-fiction work in 1952. He didn’t make much money, though, so his wife wrote ads for department stores to support them.

Dune was first published in a magazine in the early 1960s. Herbert then rewrote it and shopped it to book publishers. About 20 rejected it before it was picked up by a company that mainly sold auto-repair manuals.

Dune told the story of galactic intrigue. It centered on Arrakis, a desert planet that contained the most valuable commodity in the galaxy: a spice that made interstellar navigation possible. The novel was one of the first to promote the idea of protecting the environment.

Dune became one of the best-selling sci-fi novels in history. Roughly 20 million copies have been sold — all set on a world around the second-brightest star in the night sky.

Script by Damond Benningfield

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The Draconid meteor shower should be at its best late tonight. Bits of comet dust will burn up as they slam into the atmosphere, forming the streaks of light known as meteors. Unfortunately, though, the Moon will be in the way at the shower’s peak, so only a few meteors will shine through.

The shower gets its name from Draco, the dragon. All its meteors appear to “rain” into the sky from that direction.

Meteors sometimes survive their plunge through the atmosphere. On the ground, they become known as meteorites. Some of them are made of iron and nickel. For many cultures, these were a precious resource. And if the meteorite was actually seen to fall from the sky, then it held mystical qualities as well.

Some meteorites were made into knives, axes, and swords — perfect for killing dragons.

Egypt’s King Tutankhamen, for example, was buried with an iron knife made from a meteorite. And in ancient Rome, a meteorite was flattened to make a shield.

In 1621, a ruler in India had two swords and a dagger made from a meteorite. And in 1898, five swords were made from a single large meteorite found just a few years earlier. One of them was presented to the crown prince, Yoshihito, who later became emperor.

And in 1814, a British meteorite expert had a sword made for Alexander the First of Russia. It was intended to honor the emperor for his role in ending a war with France — giving him a truly cosmic reward.

Script by Damond Benningfield

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