What is Gravitational Lensing ? |Sci-Hut

All About Gravitational Lensing 



Have you ever seen a Star in the night and most of you might be thinking ,that these stars are exactly where you think it is.
If your answer is yes... I'm sorry , but the actual answer is no.
Now you might think that I'm a nut,  wait...
and read this blog at the end you will say awesome stuff man!!  and I hope that you will share this blog with your friends because "sharing is caring."

Before we study about Gravitational lensing we have to study about the lens and how does a lens works?

What is a lens?

Basically, a lens is a piece of curved glass which bends the light , the most basic example of a lens is your spectacles.
There  are many types of lenses like convex, concave, etc.

How does a lens works?
let me explain it with a picture- 

so, the middle part is a lens there is an observer , The person can only see the apparent object and not the real one.
 From the above picture , we concluded that-

Our eyes make image by back tracing the path. (i.e. our eyes don't support the bending of light .Unfortunately due  to this reason , we are only able to see the object either magnified or on  a  new position)

The light changes its path due to change in medium.  

Now, you guys have got  enough perquisite knowledge required  to understand the concept of Gravitational Lensing.
 Actually, it seems that there is a natural lens in our universe called Gravitational lens.
To bend light we need to make a change in the medium of light but space has no medium except gravity 

The Great Genius Albert Einstein,  said that gravity bends light. 

Due to Gravity, the light of object bends, and the observer is only able to see the apparent object either its a galaxy or a star or something else.

source-https://qph.fs.quoracdn.net/main-qimg-c91f4f2ea51cdf529845f3b4ed58a5ce.webp

The image above  may help you understand gravitational lensing better.

Who discovered Gravitational lensing? 

The gravitational lens was discovered by Dennis Walsh, Bob Carswell, and Ray Weymann using the Kitt Peak National Observatory 2.1 meter telescope.

Some more effects of gravitational lensing-

The gravitational lensing can create illusions like one galaxy can appear many apparent galaxies-

I know that you might be thinking how on earth am I supposed 

to understand image

source-https://www.nasa.gov/sites/default/files/thumbnails/image/sdss-j1004-4112-crop.jpg

Well, as you see 

there's a galaxy which is emitting light and as it gradually moves forward and  when it comes

closer to a star  for example like sun .

  We all know that stars has some superpower called gravitational energy .

Light which was passing nearby , now due to gravitation starts to bend in whole another   direction and when it reaches the Observer's eye, it creates an illusion of multiple galaxies.    

Now it's time to end this blog. 

That's pretty much it! ,  for more information visit this site-https://www.nasa.gov/content/discoveries-highlights-shining-a-light-on-dark-matter

 I hope that everything is clear now. 
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