StarDate

It’s been 44 years since any new samples of the Moon were brought to Earth. But a new delivery could arrive in a few months. A Chinese mission scheduled for launch by the end of the year could scoop up several pounds of rock and dirt.

It’ll be China’s fifth lunar mission. The second was just settling into lunar orbit 10 years ago today.

Chang’e-2 compiled one of the best maps of the Moon to date. It also scouted possible landing sites for the next mission.

After that, Chang’e-2 left lunar orbit. It orbited a point in space where the gravitational pull of Earth, Moon, and Sun are balanced. Then it headed out again, to tag along with an asteroid that passes close to Earth.

A lander and a rover followed Chang’e-2. And Chang’e-5 will continue that progression by bringing samples to Earth.

It will land atop a large mound on the edge of the Ocean of Storms, one of the dark markings on the lunar surface. The mound includes several volcanic cones. So the samples could include rocks that came from deep inside the Moon.

Chang’e-5 will scoop up dirt and rocks at the surface, and drill for more rocks from several feet below the surface. It’ll store the samples in a small rocket, which will link up with an orbiter for the trip home.

Look for the Moon climbing into good view by 10:30 or 11 tonight. Aldebaran, the bright eye of the bull, will rise to the right of the Moon, and perch below the Moon at first light.

Script by Damond Benningfield

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This month is all about Mars. The Red Planet lives up to its nickname, shining orange or red all month long. And it’s the third-brightest object in the night sky this month, after only the Moon and the planet Venus.

Mars looks so bright because Earth is passing by the planet. So Mars will spend October at or near opposition, when it lines up more or less opposite the Sun. That means it’s in view pretty much all night. And it’s closest to Earth not only for this year, but for many years to come.

Mars will be at its absolute closest tomorrow morning on American clocks — about 38.6 million miles away. We won’t be this close to Mars again until September of 2035.

Mars reaches opposition every 26 months or so, when Earth moves past the planet on our smaller, faster orbit around the Sun. Mars’s orbit is quite lopsided, though. So its distance at opposition varies by tens of millions of miles, depending on what time of year it takes place.

The best oppositions come in late summer. The opposition in August 2003, in fact, was the closest in almost 60,000 years.

This year’s is quite good as well — only about four million miles farther than the one in 2003. So Mars will be a brilliant red jewel sparkling all month long.

Tonight, look for the Red Planet in the east shortly after the sky gets good and dark, shining like a brilliant star — and remaining in view for the rest of the night.

Script by Damond Benningfield

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Draco is a pretty well-known constellation. Or at least its name is. Just about anything that’s called “the dragon” is going to attract people’s attention.

But the star pattern itself is tough to follow. It’s a meandering trail of stars that curls around the Little Dipper. But most of the stars are faint, so you need dark skies to see them. From light-polluted cities, Draco is more of a stealth dragon — hard to see in the skies above.

In Greek mythology, the dragon protected a magical apple tree planted by Hera, the wife of Zeus, the king of the gods. One of the 12 labors of Heracles — better known by his Roman name, Hercules — was to steal some of the apples. To do so, he had to kill the dragon. Hera placed the dead creature in the sky.

The head of the dragon is marked by a four-sided figure. It’s high in the northwest as night falls, far to the upper left of the Pole Star, Polaris. A couple of the stars in the head are fairly bright, but the other two are faint.

In the skylore of ancient Arabia, the four stars were mother camels. They were protecting a baby camel, which was represented by an even fainter star at the center of the quartet. The baby was being threatened by jackals or hyenas — a pair of stars that stands below the camels in early evening.

Look for the long, sinuous body of the dragon curling to the left and upper left of Polaris as darkness falls. It rotates down toward the northern horizon during the night.

Script by Damond Benningfield

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A star system in Cepheus is big and messy. And every couple of decades, it fades considerably.

VV Cephei is about 5,000 light-years away. It’s a binary — two stars locked in a mutual orbit around each other. Both stars are about 20 times the mass of the Sun. But their sizes are vastly different. One is perhaps 15 or 20 times the diameter of the Sun. But its companion is more than a thousand times the Sun’s size — one of the biggest stars in the galaxy.

The difference is caused by their stage in life. The smaller star is still in the prime of life, “burning” the hydrogen in its core to make helium. But the larger star has moved on to the next stage. That’s caused its outer layers to puff up to gigantic proportions. And a strong “wind” of charged particles blows from the star out into space.

In addition to the wind, a ribbon of gas funnels from the bigger star to its companion, forming a wide disk around the companion.

Every 20 years, the bigger star passes in front of the smaller one. Each eclipse lasts more than 21 months. That makes the system shine a good bit fainter than average. The most recent eclipse ended last year, so VV Cephei won’t fade again until 2039.

When it’s not in eclipse, the system is just visible to the unaided eye. It’s at the center of a four-sided figure that forms the body of Cepheus, the king, which is high in the north-northeast at nightfall. You need dark skies to spot this big, messy star system.

Script by Damond Benningfield

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The night sky offers three beautiful pairings as we head into the weekend. They include the four brightest objects in the night sky.

As night falls, the planets Jupiter and Saturn are in the south. They look like a pair of bright eyes, although one glistens far brighter than the other.

Jupiter is the brighter one. For now, it’s the fourth-brightest object in the night sky. Saturn is to the left of Jupiter. It’s not nearly as bright as Jupiter, but it outshines all but a few other objects.

Jupiter and Saturn are moving closer together, and will appear to almost touch each other in December.

The second pair climbs into good view by a couple of hours after sunset: The Moon and, quite close by, the planet Mars. Mars is the third-brightest night-sky object right now. And it’ll keep that ranking for several weeks. That’s because Earth and Mars are passing close to each other this month.

The Moon will move well past Mars by tomorrow night, although they’ll still be within shouting distance.

The final pair is well up in the east at first light: the planet Venus and the star Regulus. Venus is the “morning star” — the brightest object in the night other than the Moon. Regulus, the heart of Leo, the lion, stands just a whisker above it.

Venus will drop away from Regulus over the coming mornings. But they’ll stay within a few degrees of each other for a few days longer — a beautiful pairing for the dawn sky.

Script by Damond Benningfield

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The Harvest Moon lights up the sky tonight — the most popular full Moon of the year. In earlier eras, farmers used its light to harvest crops long into the night. And even today it doesn’t hurt.

There are several methods for figuring the date of the Harvest Moon. One says it’s the full Moon of September. And this year, the Moon was full on September 1st.

The most common rule, though, is that the Harvest Moon is the full Moon closest to the fall equinox. That took place on September 22nd. September’s full Moon came a full three weeks before that. By contrast, October’s full Moon is nine days after the equinox, so it wins the “Harvest Moon” honors.

One thing that makes the Harvest Moon so helpful is that, from high northern latitudes, it rises only a few minutes later each night. So for several nights in a row, the Moon is already up and shining by the time evening twilight fades away. That allowed farmers to keep right on working without a break.

The Harvest Moon won’t be the only full Moon this month. The average gap between full Moons is 29 and a half days. Since October has 31 days, that leaves enough time to squeeze in another one, on the 31st — a Blue Hunter’s Halloween Moon.

As you watch the Harvest Moon tonight, you’ll see a bright companion following it across the sky. That’s Mars, which rises to the lower left of the Moon. The planet looks like a brilliant orange star.

More about the Moon and Mars tomorrow.

Script by Damond Benningfield

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It’s four-and-a-quarter light-years to the closest planets beyond the solar system, which orbit the star Proxima Centauri. At the speed of the fastest probe ever launched, it would take about 80,000 years to get there. But one project plans to cover that distance in about 20 years — and not with one probe, but potentially with hundreds. But there’s a catch: Each probe would be the size of a postage stamp.

Breakthrough Starshot was established in 2016. Teams of scientists and engineers are studying the challenges of launching such tiny probes.

Each one would be powered by a “sail” covering a few square yards. High-powered lasers on Earth would beam light at them. The pressure of the light would accelerate the probes to about 20 percent of the speed of light within hours of launch.

A probe would carry everything it needed to conduct its mission, including cameras and its own laser to transmit information to Earth. It would have a thin coating to protect it from collisions with grains of dust.

There are lots of challenges to overcome. Today’s lasers are nowhere near powerful enough to propel the probes, for example. And at a large fraction of lightspeed, a probe would have a good view of its target planets for only seconds.

If technology continues to improve at its current pace, though, it’s possible that the first probes could be launched in a few decades — zooming toward our closest planetary neighbors.

Script by Damond Benningfield

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The Sun travels through the galaxy inside its own “bubble.” The bubble is generated by the Sun’s magnetic field, and it’s filled with charged particles carried by the solar wind. Our knowledge of conditions outside the bubble is limited. But a team of scientists is outlining a mission that would change that.

Interstellar Probe would reach a thousand times the distance between Earth and the Sun — seven times farther than any spacecraft has yet ventured. From that range, it would measure magnetic fields, cosmic rays, dust particles, and much more in the interstellar medium — the stuff between the stars. And it would look back toward the solar system to see how the Sun’s bubble interacts with the interstellar medium.

So far, our only looks at interstellar space have come from Voyagers 1 and 2. They were launched in 1977 to explore the giant outer planets. They’re still operating today. And both have passed beyond the Sun’s magnetic bubble. Voyager 1 is at 150 times the Earth-Sun distance — by far the most remote working spacecraft ever.

Interstellar Probe would use a new “super-booster” and a gravitational kick from Jupiter to reach that distance in about a decade. And it would reach its target range in about 50 years.

The mission wouldn’t launch until the 2030s at the earliest. If it takes flight, it could give us our first good look at interstellar space.

Script by Damond Benningfield

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One of astronomy’s key goals is to take sharp pictures of planets in other star systems. That’s impossible to do with current technology because the planets are tiny, and they’re embedded in the glare of their parent stars. So astronomers are working on new technologies.

One possibility is using the gravity of the Sun as a lens to bring planets into focus.

The concept is known as the solar gravitational lens. The gravity of the Sun “warps” the space around it. If you put a telescope at the right point in space, then any planets that align directly behind the Sun would form a ring of light around it. Observations over many days or weeks would allow scientists to create an image of the planet.

Such a task won’t be easy, though. For one thing, a telescope would have to be at least 550 times farther from the Sun than Earth is — about four times farther than any spacecraft has gone before.

A team led by the Jet Propulsion Laboratory is working on the concept, though. Large, thin “sails” would use the pressure of sunlight to propel the craft. That would allow it to reach its target distance in just a couple of decades.

The probe would look at a single star system, so scientists would pick a system with several planets. Then, as it sailed away from the Sun, the craft would examine each planet in the system — compiling an album of pictures of distant worlds.

We’ll talk about another long-distance mission tomorrow.

Script by Damond Benningfield

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With summer behind us, a couple of starry symbols of the season are facing different futures. One is getting ready to disappear in the evening twilight, while the other will hang on until winter.

Scorpius, the scorpion, is quite low in the south and southwest as night falls. Its brightest star, Antares, is still easy to see. But the scorpion’s body, which stretches to the lower left of Antares, and its head, to the right of Antares, are harder to pick out.

Like all the other stars, those of Scorpius rise and set four minutes earlier each day. So over the next few weeks, Scorpius will drop lower in the sky night by night. That will make it harder and harder to see. That’s especially true from locations that are farther north, where parts of the scorpion are already dipping below the horizon by the time the sky gets dark.

On the other hand, the Summer Triangle is in magnificent view at that hour. Its brightest point, the star Vega, is almost directly overhead. It’s one of the brightest stars in the northern sky, so it’s easy to pick out.

Deneb, the tail of the swan, takes its place atop the sky an hour or so later. And Altair, the third point of the triangle, moves high across the south.

The Summer Triangle sets earlier each night as well. But as we head through autumn and into winter, the Sun will also be setting later. So that extends the viewing time for the triangle into winter — making it a star pattern for all seasons.

Script by Damond Benningfield

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