Extract from ABC News
It's time to celebrate the end of the year with some fireworks — of the celestial kind.
And this year's Geminid meteor shower is set to be a cracker.
The annual event, which can be seen in the early hours of the morning from anywhere in Australia this week, is predicted to be the best we've seen for a very long time.
For a start, unlike previous years, there is no moon in the sky to hamper your view, amateur astronomer Ian Musgrave says.
"The sky will be beautifully dark," Dr Musgrave says.
We can also expect higher rates of meteors than usual in the early hours of Thursday 14 December and Friday 15 December.
And the timing is perfect if you're in party mode.
Dr Musgrave says the best time to see it will be on Friday morning with up to 63 meteors per hour predicted for Darwin and 30 per hour in Hobart.
"No-one's going to be too upset if you are bleary-eyed on Friday the 15th of December," he says.
"I don't think too many people will be expecting high performance in the weeks leading up to Christmas."
When will I see the meteors?
If you were out early this morning you may have been lucky enough to spot an occasional meteor, but you have a much better chance of seeing them on Thursday and Friday mornings.
The best time to see them on the 14th and 15th will depend upon where you live:
- Adelaide – 3:13 am ACST
- Brisbane – 2:13 am AEST
- Canberra – 3:00 am AEDT
- Darwin – 2:43 am ACST
- Hobart – 2:38 am AEDT
- Melbourne – 3:17 am AEDT
- Perth – 2:13 am AWST
- Sydney – 2:52 am AEDT
The meteor shower will start to ramp up an hour or so before these times, so the idea is to head out earlier and watch the whole show unfold.
"For Darwin, for example, you can start watching from midnight, and other sites you can start watching it from about 1 to 1.30 am," Dr Musgrave says.
To understand why the times are different, we need to unpack a little astronomy.
The Geminids are created as Earth moves through the debris of an asteroid called 3200 Phaethon.
It is usually daytime in Australia when Earth passes through the thickest part of the dust cloud, so the peak rates we see are much lower than other parts of the world where it is night.
But this year, it peaks when it is early morning in Australia, explains Jonti Horner, an astronomer at the University of Southern Queensland.
"We get good rates even if the precise peak time isn't in our morning hours, but when it lines up like this, it is even better," Professor Horner says.
From the perspective of a stargazer on Earth, meteors appear to radiate from a point in the constellation Gemini.
The meteor show starts once that point rises above the north-eastern horizon in the night sky, but it's at its best when the point is highest.
Serendipitously, this year's meteor shower is predicted to peak when this point is highest in our skies so we'll see more meteors than usual.
And over the past few decades, the meteor rates have been ramping up as we pass deeper into the dust cloud.
"Because the timing is perfect and the sky's dark, this is likely to be one of the best Geminid displays ever from an Aussie perspective — or even the best," Professor Horner says.
How many meteors will I see?
The meteors are visible right across Australia, but the further north you are, the better.
Here is a rough guide to the rates you may see in the early hours of the next three days.
The locations indicate the approximate latitude for dark sky sites, not the city itself. The darker the sky the better, but people living in urban areas will also see a good number of meteors too.
Location | Dec 14 | Dec 15 (best) | Dec 16 |
|---|---|---|---|
Adelaide | 13 meteors/hr | 35 meteors/hr | 8 meteors/hr |
Brisbane | 16 meteors/hr | 45 meteors/hr | 11 meteors/hr |
Canberra | 13 meteors/hr | 35 meteors/hr | 8 meteors/hr |
Darwin | 14 meteors/hr | 63 meteors/hr | 14 meteors/hr |
Hobart | 10 meteors/hr | 30 meteors/hr | 6 meteors/hr |
Melbourne | 11 meteors/hr | 31 meteors/hr | 7 meteors/hr |
Perth | 16 meteors/hr | 35 meteors/hr | 8 meteors/hr |
Sydney | 13 meteors/hr | 37 meteors/hr | 8 meteors/hr |
What should I look for?
Geminid meteors tend to be bright and aren't super-fast so they are easier to catch than some of the other meteor showers. There's also the occasional fireball.
"Unlike the really fast ones, you've got a good chance of seeing one move across the sky," Dr Musgrave says.
However, he adds, Geminids don't tend to leave trains of dust behind them like other meteors.
"Fast meteors leave a train after them as they streak across the sky that look like a line of smoke.
"But the Geminids are a little bit like fireworks."
Some of them can also have a bit of a greenish tinge, he adds.
"The majority will be white, but you'll see some of them with a little bit of colour."
It's unclear why the meteors can appear green, Professor Horner says.
"The colour is to some degree driven by the atmosphere rather than the material of the meteor itself," he says.
And, he adds, the brighter the meteor, the more likely it is for the human eye to detect colour.
Where should I look?
To spot these beauties you need to find Castor and Pollux — the two brightest stars in the constellation of Gemini — above the north-eastern horizon when they rise (and northern horizon at the shower's peak).
"They are the obviously brightest stars there," Dr Musgrave says.
The meteor radiant sits just below Castor, the lower star.
But the idea is not to stare at this spot. You need to scan the sky.
"They actually start their burn further up, so you may see them about a handspan above or two handspans to the right [of the radiant] and just let your eye wander," Dr Musgrave says.
Give your eyes time to adjust to the dark; you won't see anything straight away
Find a spot away from the glare of lights; the darker the better.
Make yourself comfortable; a banana lounge can be handy.
And then sit and be patient.
"The meteors don't come clicking along like clockwork," Dr Musgrave says.
"You'll see nothing for a little while, then a couple of little flurries, and then nothing for a little while.
"Be patient and you should be rewarded with some really nice meteors this year."
That is, of course, if the weather is kind.
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