The centre of our galaxy, the Milky Way, is directly overhead during these cold winter evenings, and it is here, that we find one of the most prominent constellations.

Scorpius, the scorpion is high in the sky, and one of the easiest constellations to imagine. It really does resemble a scorpion, and it too has a potent stinger, a pair of bright stars at the tip of its curving body.

The brighter star in the stinger is known as Shaula. It’s the second-brightest star in Scorpius, so it’s hard to miss. Fainter Lesath stands just above it. Both stars aren’t just in the same line of sight, they are also at the same distance from Earth, at 572 light years. The light we receive from these stars left 50 years before Columbus sailed for the Americas!

Shaula actually consists of three stars. The system’s main star is more than 10 times as massive as the Sun. At that great heft, it consumes its nuclear fuel in a hurry. It’ll soon begin to exhaust its fuel, so it’ll puff outward. The star will engulf its nearer companion, which is only a few million kilometres away. That’ll probably destroy the companion, perhaps sending its core spiralling into the core of the main star. That may hasten the demise of the bigger star, which is likely to explode as a supernova.

Lesath is a single star, but it’s also a stunner. It’s about 10 times the Sun’s mass, and it’s many thousands of times brighter. Although Shaula and Lesath appear quite close together, they’re more than 150 light-years apart. Even so, the stars are related. They were born from the same giant complex of gas and dust. This region has given birth to many massive stars, including Antares, the scorpion’s bright orange heart. But the stars are only loosely bound together, so they’re moving apart, and spreading their magnificence across the galaxy.

It’s also here, just below the tail of Scorpius, in the adjoining constellation of Sagittarius, that we find the galactic centre. The bulge of the Milky Way will be at its biggest here, as we are looking towards the centre of our galaxy. It was 271 years ago that a Prussian philosopher first recognized this band of light for what it is: the edge-on view of our own galaxy of stars. In 1755, Immanuel Kant proposed that the stars of our galaxy form a broad, flat disk. The Sun and Earth also inhabit this disk. As a result, Kant said, when we look into the disk, we see the combined glow of countless stars, which make up the band of light called the Milky Way. But when we look above or below the disk, we see only a few stars. Today, astronomers know that the Milky Way's disk is about a hundred thousand light-years across, and that we're located more than halfway out from the centre of the disk to its edge. Astronomers also know that the hottest, brightest stars in the disk form a spiral pattern. That means that the Milky Way belongs to the most beautiful class of galaxies in the universe.
The brightest stars visible along the Milky Way are generally “local”, that is, they lie within a few thousand light years of Earth. One very local star is Alpha Centauri; the brighter of the two Pointers, not far from the Southern Cross, now high in the southern sky. It’s located only 4 and a quarter light years from Earth. A mere stone’s throw away from us. In comparison, the Hubble Space Telescope has photographed galaxies whose starlight left on its journey to the Earth a whopping 10 billion years ago!

Shining brightly, low in the northeastern sky we find Vega, one the brightest stars in the sky and also one of the closest to us, at a distance of only 27 light years. The name Vega comes from ancient Arabic, and it means the "swooping eagle." Today, though, Vega's better known as the "harp" star, because it's in the constellation Lyra, the lyre or harp. It's the only musical instrument enshrined in the stars.
Higher in the northeastern sky, we find Altair, the brightest star of Aquila, the eagle. In fact, the name “Altair” means “the flying eagle.” Altair is only about 17 light-years away — closer than all but a handful of the stars that are visible to the unaided eye. Like all other stars in our night sky, Altair is moving around the centre of the galaxy at hundreds of thousands of kilometres per hour. Yet most stars are so far away that their motion is imperceptible across not just a human lifetime, but hundreds of lifetimes. Yet, because Altair is so close to us, it appears to move across the sky much faster. It will move 1 degree over the next 5000 years; about the width of two Full Moons. That motion is still too tiny for us to detect with the naked eye over our lifetime.

Higher in the sky from Altair, almost to the stars of the constellation Ophiuchus, is a star that were it not for its path across the sky, would draw scant attention from anybody. It’s only about two-thirds as big and heavy as the Sun, and only a few percent as bright. So from its distance of about 65 light-years, it’s far too faint to see without a telescope. And even with a telescope, it’s nothing more than a tiny orange pinpoint.

In about a million-and-a-half years, though, Gliese 710 should be one of the brightest stars in the night sky; about as bright as Antares, the orange “heart” of Scorpius, which is almost overhead by 10.00pm in early July.
Gliese 710 is moving toward the Sun. There’s a good chance it’ll pass about one light-year from the Sun in 1.4 million years. That’s less than a quarter of the distance to our nearest neighbour (Alpha Centauri) today. And there’s a tiny chance that it could pass within one light-week.

Even at such close range, the star wouldn’t have much direct effect on Earth; it’s too small and faint. But it could have an indirect effect. It will stir up the comets that orbit far from the Sun, sending some of them plunging toward the Sun. The closer the star gets, the more comets it’ll send our way. And there’s a chance that some of those comets could hit Earth. Depending on how big they are, that could trigger global catastrophes, wiping out much of the life on Earth. Similar to the catastrophe that led to the demise of the dinosaurs.

Let’s return closer to home and to our present time. The brilliantly dazzling planet Venus shines in the western twilight sky. It’s impossible to miss.
Do you like pancakes? I know where we can get some big ones!! Some of them are as big as a major city. There are only two problems: They’re made out of dense volcanic rock, and they’re on the planet Venus. Venus is covered with many thousands of volcanic features – lava plains, cone-shaped mountains, and structures that look like crowns and spiders. Most of the features are old, but there are hints that the planet is still volcanically active today.
The list of features includes pancake domes. There are scores of them – some by themselves, but many in groups. They’re almost perfectly round and flat. They can be up to a few dozen kilometres across, and about a kilometre tall. And their edges are steep – almost-sheer cliffs.

The domes probably formed when thick molten rock bubbled to the surface. It spread out in all directions. And it continued to spread well after the lava spigot was turned off.
A change of seasons happened just over a week ago. We moved from autumn into winter. The winter solstice arrived on June 21. This time marks the exact moment when the sun reaches its furthest northward point over the Earth and signals the onset of winter in the Southern Hemisphere.

At this time of the year, early morning sky watchers will notice that the sun rises in the northeast, arching to its highest point around noon, and setting in the northwest in the evening.
It's surprising how many people don't understand why we have seasons at all; in fact, many believe that it's because we lie closest to the sun during summer and that this causes our hot temperatures. However, our warming temperatures in summer occur mostly from how long the sun appears in our daytime sky. And that comes about because our planet's axis is tipped 23.4 degrees to its orbit around the sun. This causes sunlight to fall more directly onto one hemisphere than the other at various times of the year.

During the summertime, the sun appears higher in our sky. It rises in the southeast, swings very high overhead around midday, and sets in the southwest. In most places in southern Australia, the sun appears in the sky for about 15 hours, and is below the horizon only about 9 hours each night. This means that very little of the heat gained during the daytime can escape into space after dark, and temperatures naturally rise over time.
In the winter, just the opposite occurs. Most places see the sun only about 9 hours a day. In other words, our atmosphere loses heat during the long nights faster than it can gain it during the short days.

Of course, one of the benefits of the long nights is that you can spend even more time observing the night sky. A side-effect of spending too much time in the cold night air is that you could develop a cold, and someone probably will recommend zinc tablets to boost your immune system. And when you swallow that tablet, just remember that you're using an element created by the stars. Every atom of zinc on Earth, and throughout the universe, was forged inside stars that were nearing the end of life. When the stars died and shed some of their material or exploded as supernovae, they scattered the zinc and other elements into space, where they could be incorporated into new stars and planets.

The Moon is at Last Quarter on July 8th, at New on the 14th, at First Quarter on the 21st, and Full on July 30th.