StarDate

A half-century ago, the Moon Race was entering its final lap. Three American astronauts were about to ride an Apollo spacecraft into orbit — its first manned flight.

The race had stalled almost two years earlier. The crew of Apollo 1 had died in a fire inside the spacecraft. And the first flight of the Soviet Soyuz spacecraft ended with a fatal crash.

But on October 11th of 1968, the crew of Apollo 7 was standing by at Cape Kennedy, ready to head for Earth orbit: Wally Schirra, one of the original Mercury astronauts, and space rookies Don Eisele and Walter Cunningham. They would spend more than 10 days in space, giving the Apollo mothership and support systems on the ground a thorough checkout.

The mission was a complete success. The Apollo spacecraft performed without a hitch. That cleared the way for the next Apollo to carry astronauts to lunar orbit — bringing the United States just a few steps from victory in the race to the Moon.

And the Moon is quite low in the southwest during evening twilight tonight. It’s a beautiful crescent. The planet Jupiter stands just below it, shining like a brilliant star.

Script by Damond Benningfield

An interloper from another galaxy scoots low across the south on October evenings. It’s a tight family of stars — hundreds of thousands of them. The stars probably belonged to another galaxy that was consumed by the Milky Way in the distant past.

Messier 30 is in the lower left corner of Capricornus. It’s low in the south at nightfall. The sea-goat’s brightest stars form a wide triangle. And bright orange Mars is passing through the constellation right now, making it easier to spot.

Messier 30 is a globular cluster — a ball of stars that spans about 300 light-years. Most of the stars are concentrated in the cluster’s dense core. The numbers trail off as you move toward the cluster’s edge. Anything that wanders too far from the center gets stripped away by the gravity of the rest of the galaxy.

The Milky Way is home to more than 150 globulars. Astronomers have discovered, though, that several of them have come from other galaxies. And that includes M30.

The main clue to its origin is its orbit. As it circles the center of the galaxy, M 30 moves in the opposite direction from most of the stars and star clusters. The only way for such a massive cluster to move against the traffic is if it came from outside the galaxy. So Messier 30 isn’t a native of the Milky Way. Instead, it was pulled in by the Milky Way’s powerful gravity — making it a refugee from another galaxy.

Script by Damond Benningfield

Despite its fame as a member of the zodiac, Capricornus is a bit tough to find. It’s the smallest member of the zodiac, and one of the faintest. It forms a distinctive pattern, though — like the bottom of a bikini bathing suit. So under dark skies, you can pick it out.

The constellation represents a sea-goat. In Greek mythology, though, it was associated with the god Pan. During a battle with the Titans, he had to jump into the Nile to escape. When he did, the bottom half of his body was transformed into a goat.

The brightest star in Capricornus is Deneb Algedi — “the tail of the goat.” It’s a system of at least two stars, and perhaps as many as four.

The main star is about twice as big and heavy as the Sun, and about eight times brighter. It’s at the end of its “normal” lifetime, so it’s puffing up. So someday, it’ll be much bigger and brighter than it is now.

The star has a close companion — so close that the two stars blur together. Astronomers have to use special instruments to study it.

Two more stars appear close to this pair. All of the stars may be bound to each other. On the other hand, the two outliers may simply line up in the same direction as Deneb Algedi, and aren’t related to the sea-goat’s most prominent star.

This is a good time to look for Capricornus, because there’s no Moon in the sky, and the bright orange planet Mars is passing through the constellation. They’re in the south at nightfall.

More about Capricornus tomorrow.

Script by Damond Benningfield

 

An unpredictable meteor shower should be at its best tonight. It could even produce a rare outburst, with hundreds or more “shooting stars.”

A meteor forms when bits of dust and rock burn up in the atmosphere. Most of these particles are tiny, but they hit the air so fast that they vaporize, producing streaks of light.

Tonight’s meteor shower is known as the Draconids, because the paths of the meteors trace back to the constellation Draco. But you don’t need to know where the dragon is to watch the shower. If it appears, you’ll see meteors in all directions.

Most years, the Draconids don’t do much — only a few meteors punctuate the sky. Twice during the 20th century, though, though, the shower turned into a meteor storm — in 1933 and 1946.

This year could produce a good show, too. The comet that sheds the particles that spawn the shower passed by us just a month ago. So Earth could hit a stream of meteor-making particles.

Unlike most meteor showers, the Draconids are best observed before midnight. So you can head out to look for the meteors as soon as the sky gets dark. Your chances of seeing them are best if you get away from bright city lights. And the biggest nightlight of them all, the Moon, won’t interfere, because it’s new tonight.

The Moon is predictable, but the Draconids are not. So no one knows what will happen after dusk tonight — whether we’ll see lots of Draconid meteors or none at all.

Script by Ken Croswell

The Sun is moving across the constellation Virgo this week. Right now, in fact, it’s not far from Spica, Virgo’s brightest star. We can’t see that, of course, because of Earth’s blue skies. The atmosphere scatters blue wavelengths, creating a curtain of light that blocks the view of the stars.

If you look at the sky at local midnight six months from now, though, you’ll see the configuration of today’s noontime stars — what the sky would look like if the Sun weren’t in the way.

The change in configuration is the result of Earth’s motion around the Sun. As we orbit the Sun, its position in the sky relative to the starry background changes. In six months, it moves half way through that background. The Sun itself isn’t moving — we are.

Whatever the reason, though, there’s a different background for the Sun every day — and a different panoply of stars every night. So each star and constellation returns to the same position in the sky at the same time of year. Virgo and Spica, for example, are best seen in the evening hours during spring — six months after they’re obscured by the Sun.

At this time of year, the evening is dominated by the stars of the “celestial sea” — a group of constellations with a watery pedigree. So as night falls, we’ve got Capricornus, the sea-goat, in the south, with Aquarius and Pisces trailing off toward the east. They’re joined later by other watery constellations — enjoying their season away from the Sun.

Script by Damond Benningfield
 

The Big Dipper is plunging toward the northern horizon as night falls now, as if it’s about to dip into a pail of cool water.

Line up the stars at the leading edge of the dipper’s bowl, and follow that line to the upper right. The first moderately bright star you come to is Polaris, the Pole Star or North Star. Earth’s north pole aims toward it, so Polaris forms the hub of the northern sky — all the other stars appear to rotate around it. And it’s always at the same point above the horizon — night and day, all year long.

A star marks the south pole, too. It’s not nearly as prominent as Polaris, though. In fact, it’s barely visible.

The southern pole star is Polaris Australis. It’s also known as Sigma Octantis because it’s in the constellation Octans, which depicts a navigational instrument known as an octant.

Polaris Australis isn’t as impressive as Polaris mainly because Polaris is huge and brilliant — an especially impressive specimen.

Compared to most stars, though, it’s impressive, too. It’s more than half again the mass of the Sun. It’s expanding as it nears the end of its “normal” lifetime, so it’s several times wider than the Sun. And its outer layers puff in and out, so it brightens and fades a bit every couple of hours; on average, it’s about 40 times brighter than the Sun. But it’s also 280 light-years away. That distance keeps Polaris Australis from being a good pointer to the celestial south pole.

Script by Damond Benningfield

 

A star that’s a popular location for mythologists old and new leads the Moon into the sky early tomorrow.

Regulus represents the heart of Leo, the lion. The bright star will stand to the upper right of the crescent Moon at first light.

Regulus is a system of at least four stars. But only one of them is visible to the unaided eye. It is bigger, heavier, and brighter than the Sun. And it’s a whisker less than 80 light-years away. That’s quite close on the astronomical scale.

Regulus is not just bright. It also lies quite near the ecliptic, which is the Sun’s path across the sky. Bright stars on the ecliptic held a special significance for many ancient cultures. So the stars were given powerful names, and they held important positions in skylore.

In Babylon, for example, Regulus was known as the king. In India, it was “the mighty.” And in ancient Persia, it was one of the four “royal” stars — the guardians of heaven. Each star controlled a quadrant of the night sky. And Regulus was the leader of the gang, giving it power over the entire sky.

Regulus is a popular spot for modern mythmakers, too — the people who create science fiction. The star has been featured in several Star Trek series, for example, and in several video games. And in Babylon 5, a 1990s TV series, it was home to the first human colony beyond the solar system.

So the heart of the lion remains a popular setting for big stories.

Script by Damond Benningfield

Getting to Mercury isn’t easy. The next mission to the Sun’s closest planet will need seven years to arrive and enter orbit. And to achieve that orbit, it’ll have to fly past Earth once, Venus twice, and Mercury six times.

BepiColombo is scheduled for launch later this month. The mission is a joint project of Europe and Japan. It’s named for Giuseppe Colombo, a scientist who studied Mercury and worked on Europe’s mission to Comet Halley.

The mission will consist of two spacecraft. They’ll travel to Mercury together, shuttled by a sort of space-going Uber that’s powered by ion engines. When they get to the planet, the two craft will enter separate orbits. One will study Mercury’s composition and structure. The other will study its magnetic field and how the field interacts with the solar wind.

Only two spacecraft have visited Mercury. Mariner 10 flew past it three times in the 1970s. And Messenger orbited Mercury from 2011 to 2015. BepiColombo will build on their work, helping scientists piece together the history of Mercury. And that will help them understand how all of the Sun’s rocky planets were born.

Reaching Mercury is tough because a craft has to fight against the gravitational pull of the Sun. Each of BepiColombo’s planetary encounters will help it put on the brakes, and approach Mercury at the right angle. If everything goes well, the craft will ease into orbit in December of 2025.

Script by Damond Benningfield

The space close to Earth is getting crowded. It’s filling up with spacecraft, old rocket stages, and lots of other debris.

The space a million miles behind Earth is getting crowded, too. It’s filling up with space telescopes.

That point is known as L2. The gravity of Earth and the Sun are balanced there. So any spacecraft that goes there stays there. It’s a good spot for telescopes because their view isn’t blocked by Earth. They can be kept cooler there, too. That allows them to study some of the coldest objects in the universe.

In the last decade or so, several observatories have been sent to L2. That includes Gaia, a European craft that’s plotting the positions of more than a billion stars.

Several more observatories are scheduled to head that way soon. The biggest is James Webb Space Telescope — the biggest and most expensive space telescope ever built. It’ll study the infrared sky, so it needs to get away from the glowing Earth. Launch is planned for 2021.

A Russian craft will head for L2 next spring. Known as SRG, it’ll study galaxy clusters and map the structure of the universe. It’ll also look for black holes and the remnants of exploded stars.

And another European mission, Euclid, will join the others in 2021. It’s designed to study dark energy and dark matter. It’ll look toward intergalactic space — with no Earth to block the view.

We’ll talk about a craft that’ll go even farther tomorrow.

Script by Damond Benningfield

The most successful technique for finding planets in other star systems is known as the transit method. Astronomers watch for a star to fade a tiny bit as a planet passes in front of it. The method finds planets only in star systems with the right geometry. Even so, it’s yielded thousands of discoveries.

And it doesn’t require big telescopes to work. In fact, small telescopes are better for the job. They can watch a larger patch of sky, improving the odds of seeing a transit. And astronomers have built networks of small telescopes just for transit observations.

One that’s just getting rolling uses off-the-shelf cameras and lenses. And it’s designed for the public to participate. Using instructions provided by the project, volunteers can set up their own units for about $5,000.

PANOPTES got started in 2010, with a single camera in Hawaii. Project leaders tested the design. They also worked out ways to control the network, collect and process the observations, and make the data available to others.

Today, about a dozen PANOPTES units are under construction in the U.S. and other countries. And the goal is to add about 10 per year. They’ll be built around the world, providing coverage of the entire sky.

The project plans to support a planet-hunting space telescope known as TESS. PANOPTES observations can help confirm TESS discoveries and provide more information about the planets — big science from little packages.

Script by Damond Benningfield