Why gravity only attracts but, doesn't repel? How it came into existence? How it has influence over such large distances? How gravity truly works?

What is cosmic microwave background? What is the face of god looks like? What is the 1st light in the universe?

When you are looking at the sky, you can see a lots of starts shining. But as you see them, you are actually looking at the past, not the present. Sounds confusing. isn't it?

What is gravitational lens or gravitational lensing?

Gravity is nothing but, a curve in the space-time. 

So try to imagine that what happens when light travels trough space around a massive object lets say a galaxy.

What is Redshift? Why is it useful to Astronomers?

'Redshift'  is the phenomenon of of the light changing it's color or light shifting it's position in visible spectrum of light.

What is Supersymmetry and how it's related to WIMPs? How do the particles get their masses ?