StarDate

In more than 50 years of Mars exploration, scientists have barely scratched the surface of the Red Planet. But the next mission will go deeper. Its instruments are designed to study conditions below the surface. That will provide a better picture of how Mars is put together, and how it came together more than four billion years ago.

The launch window for InSight opens tomorrow. The craft will arrive at Mars around Thanksgiving. It’ll use three instruments to study the planet.

A seismometer will listen for “Marsquakes” — tremors set off by volcanoes, impacts by space rocks, and other causes. A probe will drill below the surface and measure heat rising from the planet’s core. And a radio transmitter will allow scientists to track the craft’s position to within about an inch. That will reveal tiny “wobbles” as Mars rotates on its axis.

Those observations will provide the best look yet at Mars’s interior. They’ll reveal the size of the planet’s core and the thickness of the surrounding mantle. They’ll also reveal the composition of the core.

That will help scientists better understand how Mars formed. Since it was born at about the same place as Earth, and from the same materials, it’ll also reveal more about the formation of our own planet — new “insight” into the early solar system.

And Mars is especially easy to spot right now. It stands to the lower left of the Moon at first light tomorrow, and looks like a bright orange star.

Script by Damond Benningfield

The first communications satellite was launched in 1960, and hundreds have followed. Some satellites scheduled for launch as early as this month, though, are going where no comsat has gone before. One will relay messages from the far side of the Moon, while two others will follow another spacecraft to Mars.

The Moon satellite will be launched by China. The country plans to land a probe on the far side of the Moon at the end of the year. Since that part of the Moon is always out of sight, the craft will need some way to relay its findings to Earth.

So China is first launching a communications satellite. It’ll orbit a point in space where the gravity of Earth and the Moon are in balance. That’ll allow it to see both Earth and the lunar farside.

The Mars satellites are known as cubesats. They’ll be launched with InSight, the next Mars lander; more about it tomorrow. The small satellites will relay data from InSight as it lands on Mars.

Several other spacecraft have served as comsats for previous Mars landers. But relaying signals was a secondary mission for those craft — they were conducting their own scientific observations. The cubesats will be the first sent to Mars just to communicate with a lander. They could help pave the way for other small Mars craft in the decades ahead.

And the Moon is almost due south at first light tomorrow. The bright planet Saturn is close to its lower left, with Mars a good bit farther along the same line.

Script by Damond Benningfield

Astronomers will be paying careful attention to the celestial serpent this month. They’re looking for a newly forming star in its coils to grow brighter. If it does, that could mean the future star is being orbited by a future planet.

The system is known as EC53. It’s in the eastern half of the constellation Serpens, which rises to the left of the Moon late tonight.

Astronomers can’t see the future star directly — it’s wrapped inside a cocoon of gas and dust. But it heats the cocoon, causing it to glow at wavelengths that aren’t visible to the eye. Astronomers watch those wavelengths with special telescopes. That helps them understand what’s happening inside the cocoon.

They know, for example, that as material falls toward the star, it first forms a wide disk. Some of its gas and dust then will fall onto the star, while some may stick together to form planets. And that may be what’s happening in EC53.

Astronomers recently saw a change in the system’s light at submillimeter wavelengths — a type of radio waves. That could be caused by a clump of material in the disk that’s forming a planet. Its gravity could regulate the amount of material that falls onto the embryonic star, changing how much energy it produces. And that could change the glow of the surrounding cocoon.

If their model is correct, the astronomers expect the system to brighten again this month — confirming that a new planet is taking shape around a new star.

Script by Damond Benningfield

For centuries, the people of the British Isles marked the beginning of summer not on the solstice, in June, but on May 1st. It’s a cross-quarter day, which comes roughly half way between a solstice and an equinox.

In Scotland and Ireland, the date was known as Beltane. People built bonfires to celebrate the longer days, and held rituals to protect their crops and livestock.

And in England, the date became known as May Day. People celebrated with village fetes, and they danced around the maypole. Dancers grabbed ribbons attached to the top of the pole, then circled around it, getting closer with each circuit.

Especially tall maypoles were erected in an area of London known as the Strand. The last of these poles was removed 300 years ago. But it found a new life — supporting one of the world’s largest telescopes.

The maypole was acquired by Isaac Newton, who had formulated laws of gravity and motion. In April of 1718, he had the pole moved to a park outside London for use by James Pound, a clergyman and astronomer.

Pound had the use of a large lens created by a leading European astronomer. The telescope was created by mounting the lens on the maypole. The eyepiece was on the ground, linked to the lens by a long wire.

Among other things, Pound used the telescope to measure the positions of the moons of Jupiter and Saturn. Newton used the observations in his calculations of the moons’ orbits — measuring a celestial dance around the maypole.

Script by Damond Benningfield

One of the most beautiful of all constellations is putting in its final evening appearance of the season over the next few nights. It soon will disappear in the Sun’s glare. The next time we see it, it’ll be in the morning sky shortly before sunrise.

Orion, the hunter, is low in the west as early twilight begins to fade. Its most prominent feature is a short line of three stars called Orion’s Belt. The belt aligns almost parallel to the horizon, and sets a couple of hours after the Sun.

Below and to the left of the Belt, look for Rigel, the constellation’s brightest star. It normally shows a brilliant blue-white color. It’s so low in the sky now, though, that the color will be washed out.

Rigel is a supergiant star. That means it’ll live a brief but spectacular life, then die an even more spectacular death — in a titanic explosion called a supernova.

Orion’s most famous star is Betelgeuse, which stands above and to the right of the belt. It, too, is a supergiant, but it’s red, not blue. That indicates that Betelgeuse may be farther along in its evolutionary path than Rigel is, and closer to that big end-of-life explosion.

Look for these two future exploding stars quite low in the western sky in early evening the next few nights. Rigel will disappear in the evening twilight within a week or so, depending on your latitude, with Orion’s Belt following a few days later, and Betelgeuse toward the middle of May.

Script by Damond Benningfield

In mythology, the god Jupiter sometimes dispatched his foes with a lightning bolt. And his namesake, the planet Jupiter, may have dispatched some early planets — not with lightning, but simply with its presence.

Jupiter is the most massive planet in the solar system — more than 300 times heavier than Earth. That gives Jupiter a strong gravitational pull, which allows it to push around many of the other bodies in the solar system.

That’s especially true of the comets and asteroids. Jupiter’s gravity causes asteroids to form two “clumps” that share the planet’s orbit — one ahead of Jupiter, and one behind. It also alters the orbits of comets.

When the planets were just taking shape, though, Jupiter’s influence might have been much more dramatic.

A study a few years ago said that several planets might have been born where Earth and the other small, rocky planets are today. But Jupiter briefly moved much closer to the Sun than it is now. That altered the orbits of the inner planets and the giant chunks of rock left over from their formation. That created a series of collisions that blasted the inner planets apart. Much of their debris spiraled into the Sun. But some of it coalesced to form new planets — including Earth.

Mighty Jupiter looks like a brilliant star. And tonight, it has a close companion: the full Moon. Jupiter is to the lower left of the Moon at nightfall, and follows the Moon across the sky later on.

Script by Damond Benningfield

Two bright lights are passing close to each other in the western evening sky. One of them is impossible to miss, and it points the way to its fainter companion.

The brighter light is Venus, the brilliant “evening star.” It’s the brightest object in the night sky other than the Moon, so you just can’t miss it.

You might mistake it for something other than a planet, though. On one hand, you might think it’s an especially bright star. On the other hand, because Venus is so bright and so low in the sky, it’s easy to think it’s an approaching airplane. And many people report it as a UFO.

In reality, it’s a planet — just in toward the Sun from our own. It shines so brightly because it’s close to us, close to the Sun, and because it’s topped by clouds that reflect most of the sunlight that strikes them.

The other bright light, to the left or upper left of Venus this evening, is Aldebaran. It marks the eye of Taurus, the celestial bull. It’s only about one percent as bright as Venus, but it’s among the 15 brightest true stars in all the night sky.

Aldebaran is dropping toward the Sun, so it’s a little bit lower in the sky each evening. But Venus is climbing away from the Sun, so it’s actually a little higher in the sky each evening. As a result, Venus and Aldebaran will stand side by side tomorrow night. After that, Venus will quickly pull up and away from its companion as it continues its long reign as the dazzling evening star.

Script by Damond Benningfield

Two big stars with quite different futures trail the Moon across the sky tonight. Their light blurs together into a single point — Spica, the brightest star of the constellation Virgo. They’re below the Moon at nightfall.

Spica consists of two stars that are locked in a tight orbit. They’re separated by just a few million miles — far closer than Earth is to the Sun.

One of the stars is at least 10 times as massive as the Sun. That great heft squeezes its core, revving up the rate of nuclear reactions. So it will live a much shorter life than the Sun will — in the tens of millions of years, versus 10 billion years for the Sun.

When that lifetime is over, the core will collapse to form a neutron star — a ball of matter about twice as massive as the Sun, but only as big as a mid-sized city. The star’s outer layers will be blasted into space, forming a supernova. For a few days or weeks, it’ll shine as brightly as billions of normal stars.

Spica’s other star is only about six or seven times the Sun’s mass. It’s still a monster as stars go. But it’s not heavy enough to trigger a supernova explosion. Instead, the star will expel its outer layers in a much gentler process. Its core will become a white dwarf. It’ll be roughly as massive as the Sun, but a little bigger than Earth — many times larger than a neutron star.

Neither star is near its end, though, so Spica should continue to shine brightly for a long time to come.

Script by Damond Benningfield

Our galaxy is so big and heavy that more than 50 smaller galaxies revolve around it. One of the first of these galactic satellites to be seen was discovered in 1954. Albert Wilson, an astronomer at Lowell Observatory in Arizona, was examining pictures of the constellation Draco, the dragon, when he noticed a faint smudge of stars. The stars belong to a small, faint galaxy that’s just 250,000 light-years away.

Like the Sun, the Draco dwarf galaxy orbits the center of the Milky Way. It’s so far out, though, that it takes between a billion and two billion years to complete just one circuit. The little galaxy’s orbit is stretched out, and it’s tilted at a steep angle to the Milky Way’s disk.

The stars in the Draco galaxy are few and faint. All together, they emit less light than the single brightest star in the Milky Way. In fact, for a long time Draco was the puniest galaxy known. And it has no gas with which to make new stars, so it’s not going to get any brighter.

In recent years, though, astronomers have spotted lots of even fainter galaxies orbiting the Milky Way. So the Draco dwarf is no longer the least luminous galaxy known.

The Draco galaxy is far too faint and spread out to see even through a telescope. But you can spot its location in the sky. The celestial dragon curls across the northeast at nightfall right now, to the right of the Little Dipper. The Draco galaxy is near the four stars that outline the dragon’s head.

Script by Ken Croswell

A telescope under construction in Chile will snap huge pictures of the sky — at least 15 terabytes of data every night. There’s no way for people to tease out all of the goodies those pictures will contain: exploding stars, exoplanets, asteroids, and many other objects.

Instead, much of the analysis will be done by computers. They’ll not only generate the images, they’ll alert astronomers to any interesting objects the pictures contain. That will allow astronomers to make more detailed follow-up observations with other telescopes.

Like other areas of science, along with business and other fields, astronomy is experiencing a data glut. Space-based and ground-based telescopes are generating huge amounts of zeroes and ones. And some projects can go on for years. When you add in the observations that have already been recorded, there’s an amazing amount of information.

So astronomers are using new computer techniques to sort through it all. One example is machine learning. The computer is fed examples of the kinds of things astronomers are looking for, and it sifts through the data to find more. Human operators confirm the correct finds and toss out the bad ones. The computer learns from those corrections. So the more data it sorts through, the better it does its job.

Among other projects, astronomers have used these techniques to classify stars and to search for exoplanets — helping them learn about the universe one terabyte at a time.

Script by Damond Benningfield