Milky Way Galaxy and COSMOS

The Cosmos is a gigantic place where there are 2 trillion other galaxies such as the Milky Way galaxy, which is our world and our solar system, as well as huge voids we call space, too many stars and planets to fit into numbers.

Even the Milky Way galaxy is currently an area where 2500 planets are named and followed, but with a total of 3.2 million planets and 50 billion stars. The “galaxy”, generally known as the Milky Way, that we see in the south direction during clear, cloudless and new moon phases, that is, in the absence of the moon or during thin crescent periods, is the clustering of millions of stars together with the gravitational force. Only one of the billions of galaxy star clusters in the Milky Way galaxy can be seen from the planet we live on as an astronomical observation. This star cluster, which has been observed since BC, is known as “Kehkeşan” in the Ottoman Empire, “Silver Road” in the Far East, and “Road of Pilgrimage” or “Royal Road” in North African and Middle Eastern countries. The star cluster, most commonly known as the “milky way” milkway, is used as the Milky Way star cluster, which is also the name of the galaxy we are in.

Mythologically, in Greek mythology, the father god Zeus was with a mortal woman and his son Heracles, known as Hercules in Roman mythology, was born. In order to make his son immortal, he leaves the mother goddess Hera to suck milk on her breast one night. Waking up after a while, Hera throws it when she sees someone she doesn’t know on her chest, and the milk that comes out of her chest squirts towards the sky and what we call milk duct occurs.

First, in ancient times BC. The star cluster, which was observed by the Greek philosopher Democritus in the years 470-350 BC, was later observed and studied for a long time by the philosopher Aristotle (384-229 BC) in the Plato school of the library of Alexandria, and first explained that it was a cluster of stars consisting of many stars close to each other. Over time, many astronomers worked on this subject, firstly the philosopher Galilee proclaimed that these are clusters of many interconnected stars in 1610. Finally, in 1750, the English scientist Thomas Wright said that they were formed by the massive gravitational force of many stars, and the cluster of stars consisting of stars close to each other is a “galaxy”. has proven to be.

The Milky Way galaxy is one of the many galaxies in the universe, and it has been determined that there are at least 200-400 billion stars and millions of galaxies in the galaxy. Towards the center of the galaxy, there are many stars close together, less frequent in the form of arms that extend away from the center. There are stars connected to the Galaxy whose lifespan ends and their lights begin to dim, and these are called “dwarf” stars.

The Sun is 28 thousand light years away from the center of the Milky Way galaxy and it is known that there are 2 trillion galaxies in the cosmos.

Accordingly, if we look at some values ​​about our galaxy;

 In cosmos subjects, the expression light year is generally used, light year is not a unit of time, but a measure of distance. Since the speed of light is 300,000 km/second, a light-year is 9.5 trillion km. means distance.

 The Milky Way galaxy, which is considered to be in the form of a large disk, is 10 light-years thick, 100 thousand light-years in diameter, and 3.5 billion years old.

 It completes its orbit in the Earth’s Milky Way galaxy in 200 million light years.

 Earth’s rotation speed in the Milky Way galaxy; 1,627 km/h

 Earth’s rotation speed around the sun, 107,627 km/h

 The speed of movement of the sun in the galaxy is 930.000 km/h

 In the Milky Way Galaxy; Considering that there are 200 billion stars and solar systems, each star has at least one or more planets, 3.2 trillion planets are accepted in the Milky Way galaxy. Of these, only 2500 planets have been named.

 The latest researches have shown that there are at least 17 billion planets the same size as the Earth in the Milky Way galaxy, whose diameter is 100-120,000 light years.

 It has been determined that there are 2 trillion galaxies in the Cosmos.

In astronomy, distances are expressed in units outside the metric system;

 1Parsec is 3.26 light years or 30 trillion km.

 1 AU (Astronomical Unit), 150 million km. This value is the distance from the center of the earth to the center of the sun.

 Earth’s equatorial circumference is 40,000 km, and the distance from the moon to the moon is 375,000 km.

Earth is the third closest planet to the Sun in the Solar System and is currently the only astronomical object known to have life and liquid water on it. It was formed more than 4.5 billion years ago, according to radiometric dating and other evidence.

 Earth/Around 40,075 km

 Age: About 4.54 billion years (4.54×109 years) of the Earth’s age

 Radius: 6.371 km

 Average orbital speed: 29.78 km/s; (107200 km/h; 66600 mph)

 Equatorial rotational speed: 0.4651 km/h; (1674.4 km/h; 1040.4 mph)

 Average radius: 6371.0 km

 Orbital period: 365.256363004 d; (1.001742096 yr)

 Equatorial radius: 6378.1 km (3963.2 mi)

 Distance from the sun: 149.600.000 km

 Area: 148.900.000 km²

 Mass: 5,972X10²⁴ kg

The fastest unmanned spacecraft ever to reach the moon, New Horinon, which was sent in 2016, passed by the moon at 45,000 km / h, the highest speed reached as an unmanned satellite vehicle today is 50,000 km / h. If we keep going at this speed, we can only reach a planet 1 light-year away from us after 22,000 years. The target that NASA wants to reach in terms of speed is 100,000 km / h. When this speed is reached, we will have covered a distance of 1 light-year in 111,000 years.

 In order to measure the varying distances and positions of constantly moving stars and planets, we need to know the angle between the star and the place we are in the world. However, since it will not be easy to measure the angular value at this distance, arc/sec or arc/second angle unit, which is 1 degree in 3600, is used.

 In space, the mass of the sun is taken into account as a unit of mass. The mass of the sun is 1 Nonillion kg, that is, 2×10 30 kg. The mass unit of the sun is taken into account within the unit of mass of other stars.

 The mass of the sun is 1,300 million times the mass of the earth and 330,000 times in volume.

 The brightness of the stars is very important and is defined by the unit of “magnitude”. The luminosity unit of the brightest star is Magnitude 6, logarithmically graded to the faintest star. As a reference, the brightness value of Polaris (the pole star) is taken into account.

 The Milky Way galaxy is 100,000 light-years across, that is, 100,000 x 10 trillion km = 1017 km. is

 The age of the universe is 13.8 billion years. In other words, the Big Bang occurred 13.8 billion years ago.

 It is accepted that the life of the sun is 10 billion years, the remaining time is 4.5 billion years. In other words, at the end of this period, it will begin to lose its sunlight and power.

 When the stars complete their lives, they first emit dim light, this situation is called “white dwarf”, and when they lose their light completely, it is called “black dwarf”.

The first discovered star in history is the star Sirus. The cirrus star consists of two period stars around each other. Sirus A and SirusB. Sirus B is a white dwarf, that is, a fading star. Since Sirus A is 2 times larger than the sun, it receives 25 times more energy than the sun and therefore appears as the brightest star. Sirus A has completed most of its 2 billion years of life, after 500 years it will become a white dwarf and gradually disappear, and we will not be able to see it in 500 million years.

Heartbeats of the Universe: Pulsars and “Sounds”;

Pulsars are neutron stars that send radio waves into space with regular rhythms like heartbeats. Pulsar, which comes from the Latin word “pulsate”, means “beating like a heart”. Stars evolve according to their mass. The smaller the mass of a star, the lower its temperature; the longer its lifespan will be. Stars with very large masses have very short lifetimes. The greater the mass of a star, the greater its temperature and diameter, but its life ends in a grandiose fashion.

Nuclear reactions occurring on the surface of massive stars create a pressure force outward from the core, which is balanced by the gravitational force. However, the hydrostatic balance of the stars that run out of their nuclear fuel is disturbed. In this case, the gravitational force of the giant star dominates the external pressure force and the star begins to collapse under its own gravity. Remember, we’re talking about a massive star. The gravitational force is so high that even protons and electrons, which are the building blocks of the atom, are affected by it. Protons and electrons cannot resist this gravitational force and come together to form neutrons. This stellar core, which is composed entirely of neutrons, begins to rotate with increasing speed due to its angular momentum due to collapse. The neutron star, which has a high temperature and magnetic field, emits X-rays from its magnetic poles into space. The resulting structure is called a pulsar.

Pulsars are neutron stars that scatter particles (X-rays) from their poles into space due to the magnetic field they have while rotating around themselves at very high speeds. A 10-15 km radius pulsar has a much higher magnetized specific gravity than a 1 million km radius sun, and its specific mass is so great that a teaspoon of neutron star weighs about a million tons. Particles of the resulting magnetic radiation scatter from their poles to the universe and can be heard from the earth as these radiation pulses (pulse) coincide and reach the earth. These sounds PSR Pulse It is called the Sourse of Radio, and each pulsar has a different recorded sound. By analyzing these sounds, information about the positions of that pulsar is obtained. These sounds, which can be listened to with special devices, are not actually “sound waves” in the real sense, they are the form of radio waves converted into sound waves and reduced to our hearing range. These sounds are called the “heartbeat of the pillars”.

What are the “black holes” and “white holes”, which are among the most important depths of the cosmos that we all have heard of and talked about from time to time, and that we are sampling?

Black hole;

A black hole, in astrophysics, is a massive cosmic body or body with a very strong gravitational field, strong enough to not allow any material formation and radiation to escape from it.

Space is also an object that is formed by the collection of a certain quantity of matter to a point. Since such objects do not emit light, they are characterized as black. Black holes, due to their “singularity”, are considered non-three-dimensional, zero-volume, and it is estimated that time flows slowly or does not flow inside them. Although not directly observable, they were discovered through observation techniques using various wavelengths. These techniques also provided the opportunity to examine many formations drifting around them. For example, because the potential well of a black hole is too deep, the accumulation in its immediate vicinity will cause the disk to reach very high temperatures due to materials falling on its disk, which will cause the emission of x-rays emitted from the disk, the black hole. Thanks to these x-rays, we can get information about square holes.

Two stars in the black hole system called HR 6819, which is only 1000 light-years away from Earth, can be seen with the naked eye from Earth. In 2019, another supermassive black hole was discovered at the center of the elliptical galaxy Messier 87, which is 7 billion times more massive than the sun. Although its horizon is only 75 kilometers wide, the acceleration created by a 10 solar mass non-rotating black hole is about 400 million times that of the earth’s surface.

The light ray emanating from a star behind a black hole is split into two by the gravitational effect of the black hole, so that star appears to be double. Such gravitational interference with light rays by gravitational sources such as a black hole or another galaxy and their apparent results are called the “gravitational lensing” effect.

white hole;

White holes are points where matter that falls into a black hole reappears elsewhere in the universe via wormholes. They can also open up to another time or another “baby universe”. Black holes are objects from which anything falling into it (including light) can escape. A black hole is formed when stars that run out of energy and begin to collapse into themselves as a result of this depletion experience massive collapses. No matter can enter the white holes, and for this reason they are called white holes.

It is the name given to the violent explosion of large stars whose energy is depleted. It is assumed that the stellar remnants scattered as a result of the explosion accumulate in other corners of the universe and form stars or star systems again.

The Sun, the planets in the Solar System, and our world were formed as a result of a supernova explosion that took place in ancient times.

Polaris, the north pole star;

The Polar Star, or Polaris, with its scientific name, is the brightest star of the Ursa Minor constellation, and since it is almost in line with the axis of the earth, unlike other celestial bodies, it does not move during the day and always points north. Because of this feature, it has been used for navigation and navigation throughout history and has taken names such as Demirkazık, Şimal star and North Star.

Polaris rotates around its axis eccentrically 23.50 degrees from the vertical, the axis of the earth is not conductively in the same direction, the difference being only three-quarters of a degree, or 44′ minutes. As the Earth’s axis changes direction over time, this difference will decrease further over the next two centuries and decrease to 25′ minutes, then the Pole Star will gradually move away from the Earth’s axis and return to the same place only after 25,000 years. Will he come back? If we live long enough, we’ll see,

The Pole Star is actually a system of three stars. The brightest star of the system, A; It is the largest yellow color and the brightest. The B star, a yellow dwarf orbiting it, was discovered by William Herschel in 1780. The existence of the third dwarf star was detected in 1929. It is about 2450 times larger than the Sun. Compared to other stars, its color is yellow.

The Pole Star is quite easy to find in the sky, it is always located in the direction of the north point of the compass. It is located 5 times the distance between these two stars, in the continuation of the two bright stars Dabne and Merak, at the end of the body of the ceiling formed by the Ursa Major constellation. It is the brightest star in this part of the sky, so it is unlikely to be confused with another star. The height of the Pole Star above the horizon will reflect your latitude. For example, in Istanbul, the Pole Star appears 41° above the horizon.

The Pole Star, as its name suggests, is only visible from the northern hemisphere, invisible from the southern hemisphere, and there is no bright south-pointing South Pole Star. But the constellation of the southern cross points roughly south to those in the southern hemisphere.

astro photography;

If you are interested in photography and are also interested in star photography, you should know some subjects about astronomy and stars apart from night shooting techniques. When you want to take a star cycle photo, you need to detect that the polaris, the north pole star is exactly in the bruise and adjust the framing accordingly.

 

best regards

Hayrettin Kagnici

September 2020