Story of Stargazing and Star Formation, Types of Nebula
Recognising the Patterns
On a good night sky, we can see many tiny little dots in the black sky, take a good look at them for the first day, come back the next night observe them again, make a habit of watching the sky every day, after some days, you'll notice there a natural pattern how they are in the sky. These tiny dots are stars, we can easily find where are the big stars, most dominant ones over the others by just, observing the sky for a couple of days. Human beings have a habit of finding out the patterns in nature. Pattern recognition is an inherent feature in us, our brain easily recognizes patterns in nature this is the reason why we tend to see animals' faces, scenes from day to day life in clouds. Often our brain links something we know to something we are experiencing for the first time to make its work easy saving its valuable energy. Our ancients have observed these patterns with the stars and gave the names of the gods, animals that they are familiar with at that time. These are constellations, a familiar arrangement of the stars in the night sky to make it easy to find directions. Although there won't be any particular explanation, or we can observe those figures we see in zodiac signs these are just imaginations, for instance, the Orion constellation shown as a fighter but in reality, we can't see it in the sky it's just an interpretation to remember that part of sky better.
Do you have a habit of watching the night sky,everyday?
Constellations and Amateur Astronomy
A constellation is a group stars that form a recognizable pattern in the sky and named after a mythological god or an animals.They move in a specific direction about the earth axis, because we know everything in the universe revolves around something. That is the advantage for the nomads, they found the patterns in the sky and predicted where would be a particular star tomorrow, the day after. And they also found the relationship between the star position and the corresponding season. This skill enabled humans to navigate through remote areas and also establish very first calendars. They are enthusiastic star gazers, very first astronomers. This is the reason that astronomy was the very first science that enabled humans to be more curious about nature,by getting more connected with it. And then the relationship between stars and humans was growing and that brought us from hunters-gatherers to a completely organized species. After some generations of the observations, early humans are very aware of the night maps and seasons so they can now start to settle. This is the first time in human history we stopped wandering and cultivate our own food instead of just hunting wild animals. This is a start of complete new era in human evolution. We started to live in built homes rather than those of scary dark caves. Literature and art found their roots because of very fact that they now no need to waste time in moving in the jungles. Fire helped them to live and protect themselves against deadly creatures, hunting tools have become more sophisticated. A step further language has came into picture this changed completely the way we communicate not only to each other but also with the future generations.
There are 66 constellations out of which 12 are zodiac signs
Technology Found its Way
The night sky that hunter-gatherers looked at is very diverse from our night sky, the reason is there was no artificial light to interfere with the natural starlight. The pure starlight travels from trillions of kilometers and reaches the eye without any interference or loss in quality. But now we have this light pollution meaning which the artificial lighting disrupts the starlight making it less likely to observe. Without light pollution, the entire Milkyway is visible in the night, but due to this, we can only find very few stars every day. This is the reason that all the observatories, space telescopes are situated far away from the city and high on mountain tops to minimize the effect of light pollution. Our technology ruined the deep sense of connection with the cosmos. we should rethink about this as this is becoming a concern for astronomers as more and more lights added to the night the worse the situation gets for stargazing.
Basic Need to Study a Star
These are stars, now we know that stars aren't just tiny little dots in the night sky but they helped our way out from walking in swampy jungles to the moon. So stars mean more to us than we normally think. Learning about how they form, evolve will have an impact on understanding the universe. So now what is a star? How stars form? Are a very good question to start in this arena.When we speak of sun our star, the sun is the source for heat and light on the planet. the light from the sun used by plants, they use carbon dioxide and water to produce glucose and oxygen, 2 most fundamental commodities for the animals to live. We all depend on plants for food either directly or indirectly. So knowledge about the sun would give us the pleasure of knowing the source behind all life on the planet. A star is a heavenly object which is mostly comprised of hydrogen. In its core, the hydrogen gets converted into helium employing nuclear fusion. Stars are fiery balls of plasma (a plasma means the 'soup' of subatomic particles which have got ripped off from atoms due to extreme temperatures), which have surface temperatures more than 5000k.
The Stellar Evolution
The terminology might seem like a scary concept if you are unaware of it but there's no such complexity. Let's dive deep into stellar evolution.
Star Formation Process
For the sake of simplicity imagine a vast free space with hydrogen gas, the conditions which replicate early stages of any star's life. Why hydrogen? Because it’s the lightest element and first formed after the big bang, by far the most abundant element in the universe. We know that everything having definite mass has an attractive pull on the other objects in its field. This is the fundamental idea for gravitation, it is true for any mass no matter how small it is it attracts. Now the hydrogen atom has a very little mass and is has very little area around to influence. Because of the random arrangement of the atoms in space, each atom has a pull over the surrounding atom. One atom becomes 2,2 becomes 3 as the more and more atoms get accumulated, forming clumps of atoms, as the mass increases attraction force becomes stronger. As time progresses the more atoms are attracted to each other forming a considerable amount of mass and then this massed body will look like a sphere. This sphere has a larger gravitational pull than the local atoms and pulls all other individual atoms around it, with time this ball gains mass. When the ball is massive enough the center of this ball(core) would not sustain the pressure from the surrounding atoms and gravity crushes the atoms such that they start to fuse, a mighty cosmic ignition takes place and there we have our star spinning, it's that simple. Gravity is the artist behind making stars. A short video above shows how stars form and also planets from the leftover matter.
Stars are massive,each of them at least weigh over 2*10^30 kg
As we know stars form out of huge spaces, where there will be hydrogen in humongous amounts, and many other elements in small amounts. They have a name they are "Nebulae". A huge amount of gas clouds spread across many light-years. These are stunning cosmic beauties, the art of the universe spread over billions of light-years.
Slowly these gases pull each other together and forming clumps these clumps grow as more mass accumulates, finally these clumps collapse under their of gravitational pressure resulting in a proto-star. The word nebula in astronomy means something that's stretch out in larger distances, distances at the span of many light-years
Types of Nebulae
The universe is too big to study, so we break it into small parts and study each of them keenly.
As the name suggests, the light gets emitted from the nebula. By absorbing the energy from the nearby star/stars, individual atoms absorb the energy and emit visible radiation. The color of the emitted light is red and ultraviolet due to the hydrogen atom(many other elements exist but hydrogen is the most dominant) because it has only one electron. The emitted radiations are highly energetic.
The light from the star gets reflected in all possible directions. The main reason for this is that the light coming from the star is not powerful enough to excite the electrons to higher states. Blue is the most dominant color because blue at the right wavelength for scattering.
These are clouds in interstellar space which just blocks the light from the background star, we can interpret them as reflection nebula but these are a special case because of the orientation of the nebula and when observed from earth.
This is a very interesting nebula because when a star is at the end of its life it'll grow and explode into a planetary nebula, meaning that star rips off all the objects in its sphere given of influence into atoms. Because planetary nebula looks like planets when seen through small telescopes, that's the reason they have this name.
The lifetime of the biggest of stars comes to an end they die with giving out the energy of billion suns in one single second this explosion outshines all the light from all the stars in the galaxy. This creates heavier elements simultaneously creating a new nebula.
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A normal star lives 5 billion years on an average. The life if the star depends on its size more massive stars die out soon as the gravity more rapidly fuses hydrogen in the core. Low mass stars live long for the same reason that gravity is not strong enough and star continues to burn dim for a larger period. The nomads had a greater and deeper connection with the light sky than us that made them first astronomers. The creative nature in our minds has helped us map the entire sky by making it into small memorizable parts, constellations have come into the picture. This enabled us to move around the world, predict seasons. Passing the knowledge to the younger generations, this had a change in thinking and the rest is history. Stars form in violent atmospheres called nebula but seen from here, they are the most artistic natural structures. Different types of nebulae have different origin but they all are mothers to billion-ton cosmic daughters.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2020 Srujith rytes