Threat from outside the solar system
(Earth revolves around the sun in an orbit similar to a shooting ring)
We know that asteroids and comets launch towards us in a random, undefined and unexpected movement from time to time.
The largest collisions in the history of the planet, caused by these asteroids, as it periodically collides with the Earth an asteroid or more
With a diameter of about one kilometer every half a million years
At the same time, this does not happen with comets.
As it does not collide with a comet the size of this asteroid only within 30 million years,
comets
They are more destructive than asteroids, because they move faster and have a higher kinetic momentum than asteroids.
For this reason, it has a greater destructive power, in addition to that it can come into Earth's orbit, from any direction in space.
In contrast, asteroids can be found in a plane close to the Earth's orbit and planets around the sun. Watch the explanatory video to see the directions of entry and meteor bombing
Oort cloud and there is a warehouse and a huge storehouse of comets and asteroids that visit the Earth and the rest of the planets of the solar system periodically.
This source of comets is a huge and sparsely dense halo that surrounds the solar system like a sphere and completely envelops it from the outside.
This dangerous cloud is located in the areas where the gravitational force of the sun ends, and this cloud is called (the Oort cloud).
This cloud surrounds the solar system from the outside and extends to more than 1,000 times the distance from the sun to the orbit of Neptune.
Comets move
Kepler's second law states that the movement of these comets is slow while they are far from the sun, and their movement accelerates as soon as they approach the range of gravity on the planets of the inner solar system, where the speed of comets increases as they approach the sun..
Oort cloud size
It is believed that there are approximately a trillion comets and asteroids inside this cloud, and this number is equal to more than 5 times the mass of the Earth, so this cloud is a storehouse of dangerous ammunition, ready to fire all the time, on the planets of the entire solar system.
The star Nemesis
In a study by the physicist (Rich Mole), a report on the movement of comets and asteroids attacking the Earth every 26 million years, resulting from the approach of the sun’s younger brother, the star (Nemesis)
Our sun as a star has a pair called the brown dwarf star, Nemesis, and 6 planets revolve around it, with their moons, and they are all called the Nemesis group.
Just as the sun runs to its stable, with its group, as well as the group of Nemesis, which converged with our group, as its entry and convergence had a great impact on the attraction and movement of distant planets such as Neptune, Uranus and the rings of Saturn
The ancient astronomical history, previously recorded such visits, but the earth was on the other side of the sun, that is, it was relatively far away, so the destruction of the earth was partial, but the earth, the star and its planets will be on the same side of the sun, so the effect of its gravity on the earth will be stronger than before.
Since the early eighties, astronomer Muller's observation of extinctions, which occurs to living organisms, has been recorded as being divided into two types:
The first type is random extinctions: they have several causes and specific conditions related to climate changes and land changes.
The second type: the most important is the major mass extinctions, which have an astronomical basis and are linked to the movement of comets and asteroids and their intersection with the Earth's orbit.
The orbit of the star Nemesis
Muller explained that there is a star accompanying the sun, and it moves in its relatively distant orbit approaching the sun every 25 million years..
This approach causes disturbances in the movement of the comets of the Oort cloud on the borders of the solar system, and this disturbance pushes comets and asteroids of large mass, to drift inward towards the planets of the inner solar system, including, of course, the Earth and its moon.
Whether this is actually the approach of the star Nemesis or others, it is certain that the Oort cloud is sensitive and unstable, especially when high-speed stars approach it.
When a star passes close to it, the spherical cloud is shaken and disturbed, and comets are sent randomly to orbits that intersect with the orbit of the Earth and other planets, but this does not happen suddenly, but rather this takes a long time, from two to three million years after the catalyst occurs, and this causes The situation is in gravitational imbalances due to the passage of the star
Comet trails in the Oort cloud
Astronomers used the tracks of comets recorded by the satellite
Astronomer (Hyparcos) in studying the motion of nearby stars.
Within the Oort cloud, they concluded that there are three or four stars passing on average near the Oort cloud and three light-years away.
This event repeats once every million years.
And their effect (those stars) on the components of the Oort cloud depends on the speed of its passage and not only its proximity.
The greatest influence in the movement of comets within the cloud is attributed to the faster passing star, which is more capable of causing gravitational imbalances.
Star Glaze 710
This star is a red dwarf located in the planet Ophiuchus, which is very weak light and you need a powerful telescope to locate it. Data from the Moon (Hyparcos) showed that the star is heading towards our solar system at a speed of approximately 55,100 miles per hour.
It will reach the field of view within a million and a half years, as it approaches and increases in brightness, to the point that it will match the brightness of the stars of the belt of Orion in the sky of the planet.
It is expected that it will reach - when approaching - a distance of about one light year from the sun, and therefore this will affect millions of comets of different sizes and push them to intersect with the Earth's orbit.
During this time span, it will become closer to us than our neighbor, the star Proxima Centauri.
Stars penetrating the cloud
The stars periodically approach the Oort cloud every 10 million years, and at this approach, they are able to scatter comets towards the inner orbits of the planets of the solar system.
It is similar to the game of bowling where the player throws the ball forcefully to hit the bowling pieces and scatter them in random directions.
This causes the approach and the gravitational interaction, the real danger to the earth, the moon and the rest of the planets close to the sun.
This was a summary of the stimuli and causes of the movement of comets coming from the Oort cloud surrounding the solar system, which is the main source, and the direct threat
To enter asteroids, comets and meteorites, with outer orbits into the solar system.
What are comets? And where it comes from? Where do comets come from? Astronomers believe that comets come from two places in the solar system, located near the outer edge of the solar system, where the sun's gravity ends and the influence of other nearby stars begins.
Kuiper belt and Oort cloud
1- Kuiper belt
The comets that complete their orbit around the sun in less than 200 years come from a disc-shaped region called the Kuiper belt. Study of comets Astronomers study the composition of comets by analyzing the light emitted by them.
This light is collected by telescopes on the ground or radio telescopes on board spacecraft.
Halley's Comet
Scientists were able to gather information by studying Halley's comet, which was discovered by the scientist Edmund Halley and was studied in 1986 AD when it periodically passed near the Earth's orbit.
? What are comets? And where it comes from
comet configuration
A comet is an icy body that revolves around the sun in a long elliptical orbit. It consists of a solid central nucleus, a cloudy envelope called a coma, and one or two tails.
comet installation
Comet Bodies Some comets have a large nucleus with a diameter of 16 km or less, and their tails extend for long distances behind them, sometimes reaching the point of being visible to the eye from the surface of the Earth.
comet diuretics
Although the orbits of comets are very far from Earth, we can only see most of them with a telescope
Comet approaching the sun
When the comet approaches the sun in its orbit, some of the surface snow evaporates and the resulting gases and particles are affected away from the sun to form the coma.
The tail of the comet is getting longer
It is one of the amazing phenomena of the universe (comets).
The most famous comets
One of the most famous comets ever discovered
Halley's Comet
Comet Halley is 16 km long and 8 km wide.
It continues for 76 years as it revolves around the sun. The British astronomer (Edmund Halley) recorded in 1757 AD his appearance at that time after his long observation of comets and understanding their movement and orbit.
Comet Shoemaker-Levy 9
Comet Shoekar-Levy 9 appears to be smashed into more than 21 pieces by the strong influence of Jupiter's gravitational pull in 1992 AD.
Part of it is 3 km wide, but it was destroyed and crushed by its violent collision with Jupiter in 1994 AD.
At that time, the astronomical observation of this event and its recording was carried out by telescopes located on Earth, as well as from aboard the Galileo space probe, which explored the comet Hecotic.
Comet Hykotec passed 15 million km from Earth in early 1996 AD.
It was the closest comet to the sun 9,000 years ago, and it appeared to observers as an icy blue dot in the distance, with a long, faint tail of gas behind it.
Comet Hill-Bopp
Comet (Hale-Bopp) approached the planet Earth in the year 1997 AD, and this is the first approach in 4,000 years, as the last visit was during the Bronze Age
What is distinctive about this comet is that it is somewhat larger than Halley's Comet, brighter and visible from Earth when it was outside the orbit of the giant planet Jupiter.
burley's comet
Comet (Burley) was discovered during the space flight that was exploring Comet Halley in 2001 AD, and it is indicated that it is unstable, unlike Comet Halley.
The most famous comets
Among the most famous comets that have been discovered are the following:
Halley's Comet: Halley's Comet is 16 km long, 8 km wide, and takes 75-76 years to revolve around the sun. The British astronomer Edmund Halley predicted its appearance in 1757 AD after observing the comets and realizing the periodic movement of some of them. Comet Shoekar-Levy 9: Comet Shoekar-Levy 9 appeared divided into 21 pieces by the effect of Jupiter's gravity in 1992 AD, the width of each part ranged to 3 km, but it was crushed by its collision with Jupiter in 1994 AD, and this event was watched by telescopes on Earth On board the Galileo space probe. Comet Hykotake: Comet Hykotake passed 15 million km from the planet in 1996 AD, where it was the closest comet to the sun for 9,000 years ago, and it appeared at that time in the form of an icy blue dot with a faint gaseous tail.
Comet Hale-Bopp: Comet Hale-Bopp came closest to Earth in 1997 AD 4,000 years ago, when it was last seen during the Bronze Age, and what distinguishes it is that it is larger than Halley's Comet, and it is also brighter than it to the point that it was visible from Earth when it was still orbiting outside the orbit of Jupiter.
Comet Burley: Comet Burley was explored during the space flight that was reconnaissance Halley's Comet in 2001 AD, and it is noted that it is strangely unbalanced, unlike Halley's Comet.
Types of comets
Scientists use several bases to classify comets, including classifying comets according to their orbital period as follows:
Short Period Comets They are comets that require a period of less than 200 years to revolve around the sun within an almost circular or elliptical orbit with an angle of inclination of rotation less than 35°. This type of comets arises from the Kuiper belt.
Long-period comets They are comets that need periods of more than 200 years to revolve around the sun at random angles of inclination. They may need thousands or millions of years to complete a revolution around the sun, and they may not revolve around it again; Therefore, it is difficult to explore and classify them. This type of Oort cloud arises. Comets that never return to revolve around the sun can be classified into two categories as follows: Parabolic Orbits; Where the comet revolves within an orbit in the form of a parabola when its speed exceeds the effect of the sun's gravitational pull on it and is sufficient to overcome it and escape from it, so it does not return to the solar system, and this explains why it did not take a circular orbit or in the form of an ellipse.
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