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If you are a meteor lover, the year 2018 has been very kind to you. Last summer, the annual meteorite rainfall of the Perseids reached its peak the day after the new moon, thus preventing the moonlight from disturbing those who see celestial streakers. And for December, the Geminid meteor shower, the most prolific of all annual exhibitions, will reach its climax when a moon almost in the first quarter will go down towards the end of the evening. This will give excellent viewing conditions.
And halfway between these two popular showers, this weekend is one of the most reliable meteor events. A kind of lesser version of the Perseids summer, the Orionid meteor shower is expected to reach its peak early Sunday morning.
These meteors get their name from the fact that they seem to come from the Orion Enhanced Club: an area just above and to the left of Orion's brightest second star, Betelgeuse, which glows a distinct reddish color . Orion is a winter landmark. Now, at the beginning of autumn, it appears in advance on the Earth in our journey around the sun. The powerful hunter does not appear completely until after 11pm. local time, when he completely cleared the horizon is. [Orionid Meteor Shower: When, Where and How to See It]
Astrophotographer Michael Humpherson captured an Orionid meteor on Panther Beach, just north of Santa Cruz, California on October 24, 2012. Credit: Michael Humpherson / www.tojustbe.co.uk
However, do not expect to see a lot of Orionid activities at this time. Instead, you should wait around 2 am in your local time zone, when Orion will have passed the horizon. And just before dawn, around 5 o'clock in the morning, Orion will appear higher in the sky heading south. It's at this point that Orionid viewing will be at its best.
In general, Orionid meteors are rather dark and difficult to see from urban areas polluted by light. So, I suggest you find a safe rural place for viewing. Lie down on a long garden chair or in a sleeping bag and look over you, towards the south of the sky.
Deceptively good circumstances
Funny thing, though: at first glance, this year looks like a very bad year to watch this shower. Only three days after the meteors reached their apogee, a bright full moon will illuminate the twilight sky at dawn on October 24th. Nevertheless, you can view the early stages of viewing in a dark sky for several mornings before Sunday.
Next Saturday night, the moon will rise in an increasing gibbous phase against the weak stars of Aquarius and reach its highest point in the sky shortly after 22 hours. local late hour. Later, Sunday morning, when the maximum activity of the Orionides is expected, the moon goes down just before 4 o'clock in the morning. There will be nearly 2 hours of black sky between the moonset and the first hour of dawn, where a single observer could count 15 or 20 orionides per hour. And as this happens when the Orionids are at their best, the moon will not seriously affect the display this year.
Halley's legacy
The annual Orionid meteor shower, composed of repeated debris from Halley's comet, extends from September 23 to November 27. It peaks between midnight and dawn on Saturday 21 October under a dark, moonless sky. At this point, the sky moves directly into the densest region of the particle field, producing 10 to 20 fast meteors per hour. Meteors can appear anywhere in the sky, but will move away from the constellation Orion. Credit: Starry Night Software
We can thank Halley's comet for this annual Orionid meteor show at the end of October. And we can also thank Halley for another meteor shower, which will appear in early May: the Etar Aquarids.
Meteoroids are the remains of the nucleus of a comet. As the sun approaches, the frozen material present on the surface of the nucleus of a comet – which usually does not measure more than one mile (1.6 to 3 km) in diameter – sublimates itself , passing directly from a frozen state to a gaseous state. In doing so, the comet turns out to be a cosmic creature leaving behind a trail of dust and debris spread out along its orbit. These pieces are so small and fragile, with the consistency of cigar ash, that you could easily crush them with one hand. Each trip requires a large amount of dusty debris scattered throughout the space.
Comets are the most primitive members of our solar system, created at the same time as the sun and the planets about 4.6 billion years ago. Yet while everything else has evolved constantly, comets have remained essentially the same and therefore contain important clues about the origins of the solar system. The reason for the unchanged nature of comets is that they spend most of their time wandering in the "deep freeze" of space, far beyond the outer planets. There, the temperature hovers a fraction of a degree above absolute zero, which equates to minus 459.67 degrees Fahrenheit (minus 273.15 degrees Celsius). In these frozen realms, no chemical reaction occurs and the comets remain as they were at the beginning of the creation of the solar system.
Over the last 100,000 years, Halley's comet has probably made over a thousand trips around the sun and, at each solar visit, the object left a calling card containing cross along its orbit. Each year, the Earth's orbit passes close to Halley's orbit in October and May, and some of the dust that has detached from the comet cuts the path of the Earth into the earth. 39; space. This debris penetrates our upper atmosphere at a speed of 66 km (41 miles) per second, creating the effect of fast trails, commonly known as "shooting stars".
Previous studies have shown that about half of all observed Orionids leave traces that last longer than those of other meteors of equivalent brightness. This is undoubtedly related to the composition of Halley's comet; the object produces meteors that start burning very high in our atmosphere, about 130 km, probably because they are composed of a light material. This suggests that they come from the diffuse surface of Halley's nucleus, as opposed to its nucleus.
I do not know how many of those who read these words actually saw Halley's comet during its last run in the internal solar system, at the end of the winter and early spring of 1986. With a period of 75.4, Halley is expected to make his return appearance in late July and early August 2061.
Currently, the average life expectancy of Americans is 78.7 years; for the United Kingdom it is 81.6 years and in Canada 82.1 years. This would seem to suggest that if you were born after 1983, there is at least a chance, better than even, to be there to welcome back the "mother of all Orionids" in the summer of 2061.
As for me, I saw Halley in 1986 at the "advanced age" of 30, so there is a good chance that I will be there when the comet comes back (you do the math).
So, I guess I'll just have to see some of Halley's kids this weekend.
Editor's note: If you take an amazing photo or video of the Orionid meteor shower that you want to share with Space.com and our press partners for a story or photo gallery, send pictures and comments to spacephotos @ space .com.
Joe Rao is an instructor and guest speaker at the Hayden Planetarium in New York. He writes on astronomy for Natural History magazine, The Farmer's Almanac and other publications, and he is a meteorologist on camera for Verizon's FiOS1 Lower Hudson Valley. Follow us on twitter @Spacedotcom and on Facebook. Original article on Space.com.
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