Extract from ABC News
If you're looking for an excuse to get out of the house this weekend, the Eta Aquariid meteor shower is back, and has the potential to dazzle with around 15 to 20 meteors an hour depending on where you live in Australia.
The meteor shower is visible during May every year as the Earth moves through the dust and gas left by Halley's Comet.
It's one of the best meteor showers for the Southern Hemisphere, and the stunning display is ramping up to peak on Monday — but you'll have to get up early to see them.
"Get up early in the morning, watch them over your morning coffee," Jonti Horner, an astronomer at the University of Southern Queensland says.
"It's one of the ones that suits the early birds rather than the night owls."
How to see it
The Eta Aquariids will peak on the morning of May 6, but astronomers suggest that — weather permitting — there should be plenty of meteors each morning from May 5 through to May 8.
This year, the shower corresponds to a new moon, so more meteors per hour will be visible in the darker sky.
"Although the peak is technically on the morning of May 6, there are better rates on May 7 when the tiny slice of the Moon is out of the way," says amateur astronomer Ian Musgrave.
"The rates this year are much better than last year when the nearly full moon was camped near the radiant."
Dr Musgrave's predictions for the number of meteors per hour for each capital city is below.
The best time to see them is when they're high in the sky, from 3:00 am local time until dawn. Before 2:00 am the meteor shower will be below the horizon and blocked to viewers in the Southern Hemisphere.
"People in the suburbs should see a meteor around once every six minutes, and in the country about once every three to four minutes," Dr Musgrave says.
"Of course they don't turn up like clockwork."
To see the meteors, find somewhere dark, look towards the east, and get comfortable. Once your eyes adjust to the darkness, there will be planets lining up to show stargazers the way.
"You've got a vertical line of planets and the Moon to guide your vision," Professor Horner says.
"There's Mercury nearest the horizon, then the thin crescent moon, then Mars and Saturn, all lined up coming from the horizon towards where this radiant point is."
The "radiant point" — the spot in the sky where meteors will appear to come from — is Eta Aquarii, a star in the constellation Aquarius.
What causes the Eta Aquariids
Meteors occur when small bits of dust and debris enter Earth's atmosphere at incredibly fast speeds.
"Something the size of a grain of rice would give you a bright fireball in the Eta Aquariids that could almost be as bright as Venus," Professor Horner says.
Meteors don't just happen during a shower, and on a regular night in a dark sky you might get lucky enough to see one or two a night. But a meteor shower is more exciting for astronomers because there's a higher frequency of meteors, they are always at the same time, and always look like they are all coming from the same area of the sky.
The Eta Aquariids is one of two meteor showers caused by Halley's comet.
While Halley's reached its furthest point away from the Sun at the end of last year, it's not completely gone. Dust and gas thrown off by the comet while it's flying through space remain behind, creating a large ring of debris in its wake.
Both the Eta Aquariids and the Orionids are caused by Earth flying through this ring of leftovers.
The reason that they're named after Orion and Eta Aquarii is because that's where it looks like the meteors are coming from. These constellations actually have nothing to do with the meteor showers — but they do provide a way to track where they're going to appear in our skies.
"Every year, we cross that debris at the same time and Aquarius is in the same position in the sky at the same time, and that's why it always looks like it's coming from there," CSIRO radio astronomer Vanessa Moss says.
"It's a huge cloud of dust, particles, and bits of rock that we're passing through, so it's always going to be a little bit different each time."
According to Professor Horner, because of the way the orbit has changed over time, this year we're passing through the trail left from over 1,500 years ago.
"The comet last intersected perfectly with Earth around 500 AD. That means that dust that was laid down by the comet around 500 AD would probably still be able to interact with the Earth now," he says.
"The dust that it shed in 1986 probably won't interact with the Earth until it's really spread out, because at the minute the comet [isn't intersecting perfectly] with Earth."
While Halley's comet still has another 38 years before it's next rendezvous with Earth, it's nice to know it'll be showering us in meteors while we wait to see it again.
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