StarDate

You might expect a constellation that bears the names of three different animals to be a bold one. Unfortunately, though, Camelopardalis isn’t. It is one of the largest constellations, covering a large wedge of the northern sky. But it just isn’t very bold. All of its stars are so faint that you have to get away from city lights to see them.

A literal translation of “Camelopardalis” is “the camel leopard.” And one astronomer who wrote about it soon after its creation in the early 1600s said that it was a camel.

But the writer was a bit confused. That’s because “Camelopardalis” is a form of the Latin word for “giraffe” — a creature that appears to combine the long neck of the camel with the spots of the leopard.

For the casual skywatcher, the semantics probably are more interesting than the constellation itself. Its brightest star is only fourth magnitude — not bright enough to see from a light-polluted city, or even most suburbs.

The star is almost 900 light-years away. So the fact that it’s visible from any place on Earth with the unaided eye tells us that it’s quite impressive. It’s several times heavier than the Sun, and about 1500 times brighter — the brightest “spot” of the camel-leopard.

At this time of year, Camelopardalis is to the upper left of the North Star as darkness falls, so it’s in fine view. It wheels below the North Star later on, and is low above the northern horizon at first light.

Script by Damond Benningfield

There are many ways to count the candles on a star’s birthday cake. Two star clusters that are in the western evening sky at this time of year provide two examples.

Messier 34 is in the constellation Perseus. It’s about half way up the sky in the west-northwest at nightfall — well to the upper right of Venus, the “evening star.” And Messier 36 is higher in the sky, in Auriga. It’s to the left of the yellow-orange star Capella.

M36 is the younger of the two clusters — less than 25 million years old. One way astronomers came up with that number is by measuring lithium in especially small, cool stars.

Stars begin life with just a smattering of lithium. And it’s quickly destroyed by the star’s nuclear reactions. More-massive stars “burn” through their lithium faster than less-massive stars. So by measuring the amount of the element in stars of different weights, they can come up with an estimate of a cluster’s age — in this case, about 22 million years.

Astronomers used stars at the opposite end of the age scale to measure the age of M34. They used white dwarfs — the small, dead cores of once-normal stars. Stars of different masses burn out at different times, with heavier stars going first. And they leave white dwarfs that have different mixtures of chemical elements. The white dwarfs in M34 indicate an age of about 225 million years — a good match to the other techniques used to count a star’s birthday candles.

Script by Damond Benningfield

Lots of folks are likely to end up with egg on their faces today — or at least on their kitchen counters. That’s because they’ll be checking out a seasonal myth. It says that you can balance a raw egg on its end on the equinoxes — but not on any other day.

And today is the vernal equinox here in the northern hemisphere — the beginning of spring. The myth is usually tied to the spring equinox, not fall. Perhaps that’s because of spring’s association with life and rebirth, which often are represented by the egg.

Here’s the basic outline of the story. At the equinox, Earth’s axis is perpendicular to the line to the Sun. That creates a special gravitational “balance” that doesn’t exist at other times of the year. This balance allows you to stand a raw egg on its end — a feat that can’t be achieved on any other date.

That’s not true at all. There’s no difference in the “balance” between Earth and the Sun than at any other time of year.

It’s easy to check it out by trying to stand an egg on end on different days of the year. The egg doesn’t want to cooperate, but with a little patience it can be done. It’s easier to accomplish if the egg has a rough shell and it’s sitting on a rough surface. But many people have accomplished the feat with smooth eggs on smooth surfaces. Just keep trying, and eventually you’ll get the egg-xact formula — on the equinox or any other day of the year.

Tomorrow: counting birthday candles in star clusters.

Script by Damond Benningfield

One of the treasures from the tomb of King Tutankhamen is an elaborate pectoral — a piece of jewelry worn on his chest that honored the Sun god. It’s made of gold inlaid with turquoise and other colorful stones. And its centerpiece is a scarab beetle made of golden glass — a symbol of the Sun god, and of the cycle of life.

 The glass formed in the Sahara Desert about 29 million years ago. And a recent study says it was the result of an impact by a big space rock.

Scientists have debated the origin of Libyan Desert Glass for decades. Some studies have suggested it formed when a space rock exploded above the surface. The resulting heat melted the desert sand, creating slabs of glass that were blasted across many square miles.

But the new study, by researchers in Australia, says the meteoroid made it all the way to the ground.

The impact melted the sand, just as an airburst would have. An impact, though, created more powerful shock waves, which rippled through the melted glass. That converted grains of zircon to a mineral known as reidite. Over time, that mineral reverted to zircon. But it left a “fingerprint” in the zircon, which the researchers discovered.

At least a couple of big space rocks are known to have exploded in the atmosphere in the last century-plus, supporting the idea of an airburst over the Sahara. The new research, though, suggests that such outbursts might be less common -- and less of a threat to life -- and to desert sands.

Script by Damond Benningfield

Mars is only half the diameter of Earth. Because it has no oceans, though, the planet has just as much land area as Earth does. That’s a lot of territory to explore — and perhaps to colonize.

And there’s a lot to see there — including some of the most dramatic features in the entire solar system.

One of those features is a network of canyons that dwarfs the Grand Canyon. It’s known as Valles Marineris — Mariner’s Valleys. It’s named for the Mariner 9 spacecraft, which studied the feature from orbit.

Valles Marineris is more than 2500 miles long — almost as long as the distance from Seattle to Miami. It’s up to four miles deep, and 125 miles wide — so wide that if you stood on one rim, you couldn’t see the other.

Mars also is home to the most impressive mountain in the solar system. Olympus Mons — Mount Olympus — is three times taller than Mount Everest. And its base covers an area bigger than New Mexico. It’s a volcano that’s been active within the last few million years — and might not be completely dead even today.

No spacecraft has yet visited either of these features — in part because the landscape is so rugged. But they’re important targets for science — and perhaps the site of adventures for future colonists.

Mars is one of two planets that huddles near the Moon at dawn tomorrow. Jupiter is the brighter of the two, with Mars just a whisker away. And a third planet, Saturn, is close to their lower left.

Script by Damond Benningfield

The Moon and three bright planets form a beautiful lineup the next few mornings. The planets align to the lower left of the Moon tomorrow, but the Moon will snuggle closer to them the following couple of days.

Two of the planets form a tight pair — Mars and Jupiter. They’re to the lower left of the Moon tomorrow. Jupiter is the brighter of the two. It’s the brightest object in the night sky after the Moon and Venus, so you can’t miss it. Mars is a good bit fainter right now, but it’s headed toward a brilliant showing later in the year.

That’s because Mars will pass closest to Earth in October. Its distance from us varies by a factor of about seven. In other words, when it’s farthest from Earth, it’s seven times farther than when it's closest.

As a result, Mars’s brightness varies by quite a bit. At its peak, it can outshine Jupiter. At its faintest, though, it’s a much more modest target. Right now, it’s toward the lower end of that range.

Jupiter stays much farther from us, so it experiences a smaller range in brightness. It never ranks lower than the fourth-brightest object in the night sky.

The final planet in the morning lineup is Saturn, to the lower left of Mars and Jupiter. It’s even farther than Jupiter is, so its brightness range is smaller. Even at its faintest, though, it’s among the 25 brightest objects in the night sky — a bright target all year long.

More about this morning lineup tomorrow.

Script by Damond Benningfield

The celestial great bear is light on his feet. His paws are represented by three pairs of stars. And all three pairs have names that mean “leap” or “spring.”

The stars of the bear’s hind leg are known as Alula Borealis and Alula Australis. “Alula” is from an Arabic phrase that means “the first leap of the gazelle.” The other pairs of stars represent the second and third leaps.

Alula Borealis — the northern member of the pair — is the brighter of the two stars. It’s a giant star that’s passed the end of its “normal” lifetime. It’s going through a series of changes in its core. Those changes have caused the star’s outer layers to puff up like a giant balloon. The star is almost 60 times the Sun’s diameter, and almost 800 times its total brightness. That makes it easy to see even though it’s 400 light-years away.

Alula Australis — the southern star — is only about 30 light-years away. It actually consists of four stars, which are split into two pairs. The leading light of each pair is similar to the Sun. The two companion stars are much smaller and fainter than the Sun, so they don’t add much to the system’s brightness.

Alula Borealis and Australis are bright enough to see with the unaided eye, although not from light-polluted cities. At nightfall, they’re well to the right of the bowl of the Big Dipper — the bear’s body. They’ll rotate high above the dipper during the night, and stand to its lower left at first light tomorrow.

Script by Damond Benningfield

Before astronauts landed on the Moon, space artists often depicted the lunar mountains and craters as harsh and jagged. The reality turned out to be less dramatic, though. Mountains and crater rims tend to be soft and rounded — far more subdued than most of the similar features here on Earth.

The reason is a process called space weathering. It works like the weathering here on Earth, where wind and rain erode geologic features. On the Moon, though, the weathering is produced by the solar wind and a “rain” of space rocks.

The Moon has almost no atmosphere to protect it from the rest of the universe. As a result, it faces a non-stop bombardment from outside.

The solar wind, for example, is a high-speed flow of charged particles from the Sun. As the particles hit the surface, some are embedded in grains of the lunar “dirt,” known as regolith. Among other things, that can create molecules of a compound that’s similar to water.

Space rocks produce more obvious effects. Big ones gouge big impact craters, and blast debris all across the Moon. But the Moon is hit by billions of tiny space rocks as well. Across billions of years, that non-stop rain has pulverized much of the surface, creating the powdery regolith. And it’s helped wear down the lunar mountains and craters — giving them a gentle profile.

Look for the Moon before and during dawn tomorrow. Antares, the bright orange heart of the scorpion, is close to its lower right.

Script by Damond Benningfield

It’s hard to think of a star that’s more than eight times the mass of the Sun as puny. But that’s the case for the least-massive star of Mintaka, which forms the right end of Orion’s Belt.

Mintaka consists of at least three stars, and perhaps more. The stars are all fairly close together. Two of them, in fact, are so close that they orbit each other once every six days.

The puny star is a member of that close pair. Its bigger companion probably is a couple of dozen times the Sun’s mass, and almost 200 thousand times the Sun’s brightness. The more distant member of the trio is only slightly less impressive.

All three stars are “burning” the nuclear fuel in their cores at a furious rate. As a result, they’ll live much shorter lives than stars like the Sun — millions or tens of millions of years, versus 10 billion years for the Sun.

The heavier stars will burn out first. And when they do, they’ll end their lives as supernovae — titanic explosions that briefly outshine billions of normal stars. The puny star appears to be on the dividing line between a supernova and a less-violent demise, so its fate is uncertain.

The stars are all “fusing” lighter elements in their cores to make heavier ones. When they die, those elements will be expelled into space. In the distant future, they could be incorporated into new stars, planets — and perhaps living organisms.

The same fate awaits the other stars of Orion’s Belt — big stars with bigger futures.

Script by Damond Benningfield

The stars of Orion’s Belt are really superstars. All three of them are among the biggest, heaviest, and brightest stars in the entire galaxy. And the star at the middle of the belt could be the most impressive of the three.

Alnilam is at least 30 times the mass of the Sun, and 275,000 times brighter. But it could be twice as massive as that, and three times as bright.

The wiggle room is caused by uncertainty in the star’s distance. Most research says it’s about 1350 light-years away. But a second look at measurements made by a space telescope put the distance at almost two thousand light-years. The farther away the star is, the bigger and brighter it is.

Regardless of the distance, there’s no doubt that Alnilam and the other stars of the belt are monsters. Because of their great heft, they’re “fusing” the elements in their cores at a furious rate. That creates enormous amounts of energy — the reason the stars are so bright.

That also creates a plethora of chemical elements, as lighter elements fuse together to make heavier ones. When the stars die, they’ll expel many of those elements into space, providing the raw materials for new stars and planets; we’ll have more about that tomorrow.

In the meantime, look for Orion’s Belt in the south-southwest as night falls, and dropping down the southwestern sky later on. The belt is a short line of three moderately bright stars. Orion's brightest stars line up above and below the belt.

Script by Damond Benningfield