A guide to what's up in the sky for Southern Australia
Starwatch - December 2024 - Sun 1st Dec 2024
Published 1st Dec 2024
The stars that shine at night do so from immense distances.
Starwatch - November 2024 - Mon 4th Nov 2024
Published 4th Nov 2024
We recently saw the destructive power of hurricanes Milton and Helene, as they cut a path of destruction through various states in the US. They left in their wake flooded businesses, broken roads, power outages, and other problems. The repair bill will run into billions of dollars.
Large Magellanic Cloud - Fri 1st Nov 2024
Published 1st Nov 2024
Distance: 163,000 light years Right Ascension 05 : 23.6 Declination -69 : 45
Starwatch - October 2024 - Mon 30th Sep 2024
Published 30th Sep 2024
After a spectacular encounter with Pluto back in July 2015, the New Horizons spacecraft was redirected to visit a more distant object, known as 2014 MU69.
OCTOBER’S DEEP SKY HIGHLIGHT - Sun 29th Sep 2024
Published 29th Sep 2024
M31—The Andromeda Galaxy Distance: 2.5 million Light Years
Starwatch - September 2024 - Sat 31st Aug 2024
Published 31st Aug 2024
Spring is just around the corner, and with it, comes the promise of warmer evenings and clearer skies. And hopefully the opportunity to spend more time looking up!
NGC 253 – Galaxy in Sculptor - Fri 30th Aug 2024
Published 30th Aug 2024
NGC 253 is the brightest member of the Sculptor Group of galaxies.
Starwatch - August 2024 - Tue 30th Jul 2024
Published 30th Jul 2024
f you're brave enough to venture outside these cold winter nights, you'll be greeted by the heart of our Milky Way galaxy directly overhead. Find yourself a dark space in your backyard on a clear moonless night, and look straight up.
The Swan Nebula - Mon 29th Jul 2024
Published 29th Jul 2024
M17 – The Swan Nebula in Sagittarius
Starwatch July 2024 - Mon 8th Jul 2024
Published 8th Jul 2024
Look up overhead on any of these frosty winter’s nights, and as long as you have a dark area away from direct lighting, you’ll see the band of the Milky Way shining brightly.
Merging Galaxies - Sun 7th Jul 2024
Published 7th Jul 2024
NGC 4038-4039 Merging Galaxies - The Antennae. Distance: 45 million Light Years.
Starwatch June 2024 - Sun 2nd Jun 2024
Published 2nd Jun 2024
About half-way up the northern evening sky, a bright star shines.
The Trifid Nebula - Sat 1st Jun 2024
Published 1st Jun 2024
M20 – The Trifid Nebula in Sagittarius
Starwatch May 2024 - Thu 2nd May 2024
Published 2nd May 2024
A myriad of bright stars adorn the late autumn evening sky.
Galaxy NGC 5128 - Wed 1st May 2024
Published 1st May 2024
Galaxy NGC 5128—Centaurus A
Comet Pons-Brooks - Wed 10th Apr 2024
Published 10th Apr 2024
Looking west on the evening of April 27., 30 minutes after sunset. Locate the orange star Aldebaran, then scan to the left until you come to a fuzzy spot in the sky. Train your binoculars on it, the comet will be 239 million kilometres away. Graphic generated with Stellarium planetarium software.
M104 - The Sombrero Galaxy - Tue 9th Apr 2024
Published 9th Apr 2024
M104 - The Sombrero Galaxy. Distance: 31 Million Light Years
Starwatch - April 2024 - Mon 8th Apr 2024
Published 9th Apr 2024
Some of the brightest stars in the whole sky can be seen during these crisp autumn evenings.
Starwatch - March 2024 - Wed 6th Mar 2024
Published 6th Mar 2024
What a wonderful time of the year this is to be observing the night sky. The weather is warm, the nights clear, and the Milky Way shines directly overhead!
Object of the Month - Mon 4th Mar 2024
Published 4th Mar 2024
Eta Carinae Nebula (NGC 3372)
Distance: 7500 Light Years
Right Ascension: 10 : 43.8 | Declination: -59 : 52
The stars that shine at night do so from immense distances.
In fact, stars are so remote that astronomers rarely use kilometres to express their distances. That's because even the brightest stars aren't millions or even billions of kilometres away, but trillions or quadrillions.
To avoid such cumbersome numbers, astronomers use a different unit of distance: the light-year. That is, the distance that light travels in one year. Since light travels fast, at 300,000 kilometres per second, even a single light-year is an immense distance; over 9,000,000,000,000 kilometres!!
The summer night sky is blessed with an abundance of bright stars. As a matter of fact, 8 of the 10 brightest stars in the whole sky are visible on summer nights.
Let’s begin our tour with Sirius, the brightest star in the night sky.
Sirius looks so bright for a couple of reasons. First, it really is bright; it produces about 30 times more energy than the Sun. And second, Sirius is less than nine light-years away. Only a few stars are closer.
Sirius is actually a binary, two stars that move through space together, bound by their mutual gravitational pull. The star that we see with the unaided eye is Sirius A. The other is Sirius B. Since Sirius is known as the Dog Star, Sirius B is nicknamed “the Pup.”
Sirius A is a main-sequence star. That means that like the Sun, it’s in the prime of life. Sirius B, on the other hand, is a white dwarf — the burned-out core of a once-normal star. It shines only by releasing the intense heat it built up during its long lifetime. It’s so small, and so close to Sirius A, that you need a telescope to see it.
Canopus, the second brightest star in the sky is located higher in the southeastern sky. Canopus is quite different from the Sun. It's a supergiant; many times bigger and heavier than the Sun. It's also more than 10,000 times brighter than the Sun, so it's easily visible across more than 300 light-years of space. It's nearing the end of its life, and within the next few million years should explode as a supernova. When that happens, Canopus will briefly outshine everything else in the sky except the Sun.
Hugging the southern sky at this time of the year is Alpha Centauri, the third brightest star in the sky, and our closest stellar neighbour, at a mere 4.25 light years. Arcturus, the fourth brightest and Vega, the fifth brightest are not visible at this time of the year. They illuminate the cold winter skies.
Sixth placed, yellow Capella hugs the northern horizon. Rigel and Betelguese, in Orion, are placed seventh and tenth respectively. In eighth place, Procyon, makes an appearance late in the evening in the eastern sky, whilst in ninth place, Achernar is almost overhead.
Of course, December is Christmas month, and if Santa is especially generous this year, you might find something shiny in your Christmas stocking: gold. As you admire it, think about this: that bit of soft, beautiful metal just might have been created during the birth of a black hole.
Almost all of the chemical elements are created by stars, either during their long lifetimes, or in supernovae; the explosive deaths of heavy stars. But some recent research says that some of the heaviest elements may require multiple stellar deaths.
These heavy elements, including gold, are the result of the merger of two neutron stars; the corpses of once-mighty stars that had already exploded. The collision forms a black hole. But the violent outburst that accompanies the merger blasts away some material before it can fall into the black hole. The ejected material includes some of the heaviest elements, which are difficult if not impossible to make in normal supernova outbursts. This includes a lot of gold. A typical merger could produce enough gold to make 10 Moons!
These kinds of mergers are rare, there’s probably only one every hundred thousand years in our own galaxy. But the researchers say that over cosmic time, they could account for all the gold in the universe.