Space / A Leonid meteor storm like the one that will be seen tonight in the skies of Israel is expected next time only at the end of the 21st century
Avi Blizovsky
Leonid meter of 1966 - 150 thousand meteors per hour
https://www.hayadan.org.il/leonid161102.html
One of the most famous meteor showers will reach its climax this week over Europe and North America, sending hundreds of thousands of fireballs all over the atmosphere.
However, the Leonids may show a paler display than last year, which was one of the best in several decades. Despite the larger number of meteors expected this time, they may disappear in the glow of the moon and other bright objects that will light up the night sky.
The annual meteor shower occurs every November when Earth crosses a long strip of debris and debris left here by Comet Temple-Turtle, which approaches Earth's orbit once every 33 years. The tiny fragments, most of them no bigger than a grain of sand, heat up and vaporize as they pass through the atmosphere at a speed of 260 km/h.
These evaporating particles create flashes of light, sometimes brighter than the moon or even the moon. The Leonids in particular are known for their great brightness and the distance they travel before disappearing. The concentration of meteors varies randomly from year to year, depending on whether the Earth is passing through a thick or thin cloud of debris. This year, Earth crosses not one but two remnant clouds, which will provide two peaks six hours apart between November 18 and 19.
The first one may be seen over Europe at four in the morning according to Greenwich time on November 19 (500 in the morning Israel time, right on the verge of sunrise). You should watch from rural areas, as far as possible from city lights, and then you will be able to see between 2,000 and XNUMX Leonids an hour, says Bill Cook of NASA, who helps calculate the meteor forecast. Later, the Earth will pass through a thicker cloud, two, six and a half hours later. Watchers The US will be able to see up to XNUMX meteors per hour, says Cook.
During the 2001 show, some viewers saw up to 10,000 meteors an hour. It was the largest concentration of meteors since 1966, when 150 shooting stars were seen per hour at the peak. Unlike the shower of 2001, the shower of 2002 will be accompanied in an unwanted way - the full moon expected to cover the light of pale meteors.
"The moon will reduce the number of meteors we can see," says Cook, "and therefore we included that in the calculation."
Still, some in North America are encouraged that the meteors will be visible on the East Coast shortly before sunrise, when the moon is low in the western sky, and then you can try to look for a spot where the moon will be hidden by buildings or hills, suggests Rob Suggs, another researcher at the Marshall Space Flight Center in Huntsville Alabama.
Wait for the moon to be low over the horizon
By Eran Ofek
Tonight (November 19-18) the Leonid meteor shower will be visible in the sky in Israel, after midnight until the early hours of the morning. According to the forecasts, from the Mediterranean region and from Israel in particular, it will be possible to see the first peak of the meter, of its two peaks that will be visible from Earth. Despite the predictions that estimate the predicted rate of meteors at about 3,000 meteors per hour, a full moon will "cloud" the event - the moonlight scattered in the Earth's atmosphere makes the sky appear bright - and will reduce the rate of meteors significantly, about 10 times.
A meteor is the phenomenon seen when a grain of dust enters the Earth's atmosphere at a speed of several tens of kilometers per second. At such a speed, the dust grain (meteoroid) collides with the air molecules, heats up, and burns up at an altitude of about 100 km. This violent event causes the electrons to be torn from the air molecules - a phenomenon called ionization. The result is that the ionized air emits light in a process similar to a fluorescent lamp. The emission of light It looks like a meteor to us (also called a falling star, but as mentioned it has nothing to do with the stars).
Every night, in a dark sky, you can see meteors at a rate of 15-5 per hour. Sometimes, when the Earth passes through a concentrated swarm of dust grains left behind by a comet, we see a phenomenon called a "meteor shower".
Since all these dust grains move together in adjacent and parallel orbits, the meteors appear to the human eye as if they were coming from a single point in the sky. This phenomenon is known as "perspective", and similar to train tracks that appear to us as if they come out of one point, when in fact they are parallel - so are the meteors in meteors' goals. The meteor shower is usually named after the constellation from which the meteors are seen coming out.
When a meteor shower occurs, meteors are visible everywhere in the sky, but if we throw their tracks back, across the dome of the sky, we will notice that they converge at one point. The Leonid shower is so called because the meteors look as if they come out of the constellation Leo.
Comet Temple-Tuttle, responsible for the Leonid shower, orbits the Sun once every 33 years, and last time it passed close to the Sun in February 1998. Therefore, in the years following its passage, we get stronger than usual Leonid showers. Several dozen meteor targets are known today, but most of them are weak targets, yielding individual meteors every hour. Only a few of them have reasonable rates of about 100 meteors per hour. The strongest of these are the Chondratid shower, which peaks on January 4th in the morning, the Perseid shower which peaks on August 12th, and the Geminid shower which peaks on December 14th.
Meteor research has been booming in recent years, both because meteorites contain organic matter and may have something to do with the appearance of life on Earth, and because meteorites may disable the delicate electrical systems in satellites orbiting the Earth. That is why the various space agencies are interested in accurate predictions about the dates of occurrence of extremely strong meteor targets.
Every year the Leonid meteor is a moderate meteor, which produces about 20 meteors per hour. But in some years the Earth passes through particularly dense areas in the swarm of dust grains and then we may see rich spectacles - meteor storms. Such were seen in 1998 with 400 bright meteors per hour, in 1999 with 4,000 meteors per hour, in 2000 with about 500 meteors per hour, and in 2001 with 4,000 meteors per hour.
The Leonid storm in 2002 will be one of the last in the coming years. The next time the Leonid meteor shower is predicted to produce a higher rate than usual will be in 2006. The conditions in Israel will be almost optimal, but the rate of the meteor will only be about 100 meteors per hour, much lower than what we have been used to in recent years.
Due to the passage of comet Temple-Tuttle in close proximity to Jupiter and Saturn, which will change its orbit, no Leonid storms will occur the next two times the comet passes near the Sun, and the next storm of the Leonid shower is expected only in 2098 or 2131.
Last chance for 100 years
Climax of a meteor storm. The "heavenly show" expected tomorrow, actually ends a season of "meteor shower" storms, tomorrow's meteors will be the last in terms of strength for the next hundred years
Dr. Noah Brosh, 16/11/2002
Tomorrow - and in fact before sunrise on November 19 - a storm of meteors is expected to occur, due to the activity of the "Leonids". If there is no limiting cloudiness, it will be possible to observe it in the sky of Israel.
The meteors are tiny fragments from a comet and appear every year in mid-November. Since the comet orbits the sun in a very long orbit - and the emission of fragments occurs close to its closest passage to the sun - the result is that every time it passes near the sun, a cloud of comet fragments is formed. If the Earth's orbit passes through a particularly dense debris cloud - a meteor storm occurs.
The expected storm tomorrow and towards Tuesday morning, may rain at peak activity, one meteor every second. The particles that will be seen in Israel were ejected from the comet back in 1767. Viewing Israel from the ground will not be easy, because of the strong light of the full moon, which will be in the western part of the sky for the next two days.
The "meteor shower" as a phenomenon is related to the rapid passage of a cosmic grain in the Earth's atmosphere. Because of the high speed, the air molecules break up into ions and electrons. When these reconnect, light is emitted - and this is one of the components of that phenomenon known in the vernacular as "falling stars".
The disintegration of the air molecules comes as a result of a lot of heating, which occurs mainly in the front part of the meteor. The movement, at a high speed, compresses the air, even though it is very thin at the height where the meteors "are" in space (about 100 km above us) and due to the compression, heat is generated that reaches about 4000 degrees.
In this process, the texture of the meteor also heats up and evaporates. Usually, the entire meteor turns into gas even before reaching a height of about 70 km. But rarely, and when the meteor is particularly large, part of it reaches the surface of the earth. This fraction is the meteorite.
The meteor shower known as the "Leonides" is so named because the meteors appear to burst out of the constellation "Aria" (Leo). These are the fastest of the meteors, and hit the atmosphere at a speed of about 72 km per second. At this speed, the distance between Metula and Eilat can be covered in 6 seconds!
Usually, due to an "oblique" entry into the atmosphere and strong braking of the meteor, the length of its illuminated path is only a few tens of kilometers. The typical size of the comet fragment is like a grain of sand on the seashore - and even smaller.
At the same time, the origin of the material from which the meteor is made is in a comet. The study of meteors helps to understand the nature of comets in general. The meteors bring with them to the earth, in their fall, different types of heat and bitterness - including organic matter.
Tomorrow's event ends a season of meteor storms that culminates in the "Leonid Shower". The reason:
A deviation occurred in the comet's orbit and the debris clouds it left behind. It will be caused by the gravitational pull of the planet Jupiter.
After the peak of this storm, a small record is expected to be set - about a hundred meteors per hour only - in an event that will take place in 2006 and perhaps in 2007. After that, a pause of about a hundred years in meteor activity is expected - so that tomorrow will really be the last chance for all of us to see an impressive meteor storm.
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~374540451~~~56&SiteName=hayadan
