The 2021 Eta Aquariids Meteor Shower

Location of the Eta Aquariids radiant looking east to southeast. (Astronomy Now)

Look up! The Eta Aquariids Meteor Shower has begun on April 19th and will continue through May 28th. We’ll be moving through the peak of the Eta Aquariids Shower on May 5th into May 6th this week. However, weather conditions are not forecast to be favorable.

What is the Eta Aquariids Meteor Shower?

According to NASA, the Eta Aquarids peak during early May each year. Eta Aquarid meteors are known for their speed. These meteors are fast—traveling at about 148,000 mph (66 km/s) into Earth’s atmosphere. Fast meteors can leave glowing “trains” (incandescent bits of debris in the wake of the meteor) which last for several seconds to minutes. In general, 30 Eta Aquarid meteors can be seen per hour during their peak.

Where Do The Meteors Come From?

The Eta Aquariids meteor shower peaks each year in early May. Meteors appear to radiate from the constellation Aquarius. (Sky & Telescope)

Meteors come from leftover comet particles and bits from broken asteroids. When comets come around the sun, they leave a dusty trail behind them. Every year the Earth passes through these debris trails, which allows the bits to collide with our atmosphere where they disintegrate to create fiery and colorful streaks in the sky.

The pieces of space debris that interact with our atmosphere to create the Eta Aquarids originate from comet 1P/Halley. Each time that Halley returns to the inner solar system its nucleus sheds a layer of ice and rock into space. The dust grains eventually become the Eta Aquarids in May and the Orionids in October if they collide with Earth’s atmosphere.

Comet Halley takes about 76 years to orbit the sun once. The last time comet Halley was seen by casual observers was in 1986. Comet Halley will not enter the inner solar system again until 2061.

Comet Halley was discovered in 1705 by Edmund Halley. Edmund Halley predicted the orbit of the comet through past observations of comets, suggesting that these sightings were in fact all the same comet. Halley is perhaps the most famous comet—it has been sighted for millennia. This comet is even featured in the Bayeux tapestry, which chronicles the Battle of Hastings in 1066.

Comet Halley’s dimensions are 10 x 5 x 5 miles (16 x 8 x 8 kilometers). It is one of the darkest, or least reflective, objects in the solar system, with an albedo of 0.03.

The When & Where: Eta Aquariids Peak

Meteor showers are very predictable events, so astronomers know exactly when you have the best chance of seeing them.

The shower is forecast to peak on the morning of Friday, May 6th, with good activity from the 4th through the 8th. Counts typically range from 10-20 meteors per hour, averaging around 10. In 2021, the peak of the Eta Aquariids is expected just before sunrise on Friday, May 6th.

In the case of the Eta Aquarids, the radiant doesn’t rise until long after midnight, and it reaches its highest in the sky well after sunrise. So the best time to watch for meteors is anywhere from one to two hours before sunrise. Earlier than that, the radiant is too low — any later, the sky is too bright. You can use an AR app like Night Sky on your smartphone to track down the constellation.

Conditions for Viewing

Where to look in the sky during the peak of the Eta Aquariids Meteor Shower (timeanddate.com)

The Eta Aquarids are viewable in both the Northern and Southern hemispheres during the pre-dawn hours. The Southern Hemisphere is preferable for viewing the Eta Aquarids. The Northern Hemisphere has an hourly rate of only about 10 meteors. This is due to the viewing location of the radiant from different latitudes. The constellation of Aquarius—home to the radiant of the Eta Aquarids—is higher up in the sky in the Southern Hemisphere than it is in the Northern Hemisphere. In the Northern Hemisphere, Eta Aquarid meteors can more often be seen as “earthgrazers.” Earthgrazers are long meteors that appear to skim the surface of the Earth at the horizon.

To view the Eta Aquarids find an area well away from the city or street lights. Come prepared with a sleeping bag, blanket, or lawn chair. Lie flat on your back with your feet facing east and look up, taking in as much of the sky as possible. After about 30 minutes in the dark, your eyes will adapt and you will begin to see meteors. Be patient—the show will last until dawn, so you have plenty of time to catch a glimpse.

But, there are impediments for viewing in Trinidad and Tobago.

Firstly, light pollution is a major issue in most populated areas across Western and Northern Trinidad and the Western half of Tobago. Unfortunately, there is little you can do about this beyond traveling into darker areas such as parts of Northern Coastal Trinidad or Eastern and Southern parts of the island.

Secondly, weatherwise, an variably cloudy night is forecast as increased showers and possible thunderstorms are anticipated on Friday into Saturday.

It’s Meteors – Not an Asteroid to Comet

Down-to-earth Journey of a Meteor Image: Space.com
Down-to-earth Journey of a Meteor Image: Space.com

It may be self-explanatory, as it is literally in the name of the shower, but the “shooting stars” you may see in the skies over the next several nights are meteors.

The terminology of these space objects matter, as a meteorite would have impacts to land, while a meteor does not.

Have you ever wondered what’s the difference between a meteor and a meteorite or an asteroid, meteoroid or comet? Here are the answers to all your questions regarding Meteor Terminology. Image: Vincent Perlerin/AMS

Meteor and meteorite strikes are more common than you might think. Dust-grain size meteoroids strike the Earth’s atmosphere almost constantly, but they often go unnoticed. Meteoroids between a millimeter and a centimeter burn up in the atmosphere and appear to us as shooting stars.

Larger strikes are less common—a one-meter meteoroid strikes the Earth once each year on average and would reach the ground as smaller debris, while a 100-meter meteoroid strikes the Earth approximately every 10,000 years, according to a Tufts University fact sheet. Meteoroids over 1 kilometer hitting Earth are catastrophic events that occur every 1 million years on average.

Meteoroids do not discriminate where they land, nor where they enter the earth’s atmosphere. Hence, it is well within the possibility that events such as this could happen across Trinidad, Tobago, or any other Caribbean islands.

But medium-size strikes can be dramatic spectacles—and in some cases, dangerous. The Chelyabinsk meteor that struck southern Russia in February 2013 blew out windows and caused indirect injuries to almost 1,500 people.

Tips for Viewing

via EarthSky.org

1. Realize that this shower rises gradually to its peak. Few meteor showers are a one-night event. You could start tonight!

2. Be aware of the time of moonset each night. As much as possible, in the weeks between now and the peak, you’ll want to be out looking after moonset. 

3. Watch in the hours before dawn Most meteor showers are best after midnight. After midnight, the part of Earth you’re standing on has turned into the meteor stream, which means the radiant point for the shower will be above your horizon.

4. Avoid city lights. This should go without saying, but just a reminder. A wide-open area – a field or a lonely country road – is best if you’re serious about watching meteors.

5. Camp! Nothing beats a set-up before the night begins. Of course, you’ll never see as many meteors in the evening as you will after midnight, but – if you are watching during the evening hours – you might catch an earthgrazer, which is a slow-moving and long-lasting meteor, traveling horizontally across your sky. Earthgrazers might be seen even in bright moonlight. They tend to be seen in the late evening or around midnight.

6. Make yourself comfortable. Sprawl out upon a reclining lawn chair, with an open sky view. Bring along a blanket or sleeping bag. Your eyes can take as long as 20 minutes to adapt to the dark, so give yourself at least an hour of observation time.

7. Watch with friend or friends, and try facing in different directions so that if someone sees a meteor, that person can call out – “meteor!” – to the rest.

8. Notice the meteors’ speeds and colors, and watch for meteor trains.  A meteor train is a persistent glow in the air, left by some meteors after they have faded from view. Trains are caused by luminous ionized matter left in the wake of this incoming space debris. They linger for a moment or two after the meteor has gone.

9. Embrace the night. We hear people bubble with excitement about seeing meteors in all sorts of conditions – moon or no moon – city lights or no city lights. So, camp out and make a night of it! Read more.

Check out other stories on celestial events.

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