THE SPACE DISTANCE

 

 SPACE DISTANCE

PART-2.

GNZ11 is the farthest Human discovered Galaxy in the Universe till now. It is at a distance of 32 billion Light Years from the Earth. How do we find the distance of that Galaxy? In the last post, We learned to measure the distance of the objects that present below 32,000 Light Years by using Parallax Effect. In this post, We'll see the continuation of the HR Diagram. Let's see about it.

GLOBULAR CLUSTERS:

The Universe is occupied by the Stars and Galaxies. If you notice a Star, You can easily know the Color of the Star and by using Telescope we can able to find its Apparent Brightness. But, we want its distance. Let's go again to the HR Diagram. The colored dots indicated the Millions of Stars. In this Equation, B=L/4πD², If the values of B and L are known, We can find the distance. We know the Apparent Brightness. But, What about the Luminosity? To find Luminosity, We compare the Color of the Star to the HR Diagram. Let's consider, The Star you find is a Red-Colored Star. But, We don't know about its nature.

It may be a Red-Dwarf or Red-Giant or Red-Super Giant. So, the exact value of Luminosity is not found. Here, You notice only a single Star. We want to notice the group of Stars. These group of Stars is called as GLOBULAR CLUSTERS. For example, We take Omega Cluster. It contains almost 10 Million Stars. We draw an HR Diagram to this Cluster. If you compare this HR Diagram of Omega Cluster to the original HR Diagram, The pattern that matches is the Luminosity Value. Hence, we can find the distance of the objects that present far from us. Using this method, We can find the distance of objects that present below 1,60,000 Light Years. How can we find the distance of objects that present after 1,60,000 Light Years? 

CEPHEID VARIABLE STARS:

We need an important instrument to measure the distance of objects away from 1,60,000 Light Years. That instrument is a type of a Star. The name of the Star is Cepheid Variable Stars. This Star can increase and decrease its brightness. It takes time to increase or decrease. It is said to be Period of Stars. A Scientist plot a Graph of Period against Luminosity. The final Graph is a Linear Line.

Therefore, If the period increases, Luminosity also increases. This is helpful in finding distances of Galaxies too. But, below 1,60,000 Light Years. These type of Stars emits brightness that is million times greater then our Sun. These Stars can easily visible below 55 million Light Years. But, What about after 55 Million Light Years? Super Nova helps us to find the distances of the objects that present after 55 Million Light Years. There are many types of Super Nova. We use Type-1A Super Nova. How a Star becomes Super Nova? In a Binary Star System, A White Dwarf Star has more mass than another Star. It absorbs the entire mass of the entire Star until it attains the Chandrasekar Limit. If it crosses the limit, It becomes Super Nova. This Super Nova emits brightness that is 5 Billion times greater than our Sun. The brightness is almost equal to the brightness of the Core of its Galaxy. This is used to find the distance of the Galaxy that present below 10.5 Billion Light Years. Super Nova used to find the distance of the Galaxy that present below 10.5 Billion Light Years.

THE CONCLUSION:

Red-Shift, It forms because of the Expanding of Universe. We'll see it in next post. But, A small information in this post. Sun's light takes 8 minutes 20 seconds to reach the Earth. We see the Sun which is  8 minutes 20 seconds before. The farthest Galaxy GNZ11 is present in 32 Billion Light Years away from us. You think that GNZ11 we see now is 32 Billion Years before. But, It is completely False. Let's see in next post. Stay Tuned.