# Space to a Layman

This blog is to give a brief introduction to space-time. SPACE in the term of a dictionary is a void or a state of being empty. For example “I have lots of space for you in my heart” or “is there any space in the storeroom?”

This is the basic idea about space. but to one with curiosity about the universe will ask “what space really means? ” The answer to this question is complicated yet simple.

# Space in science.

Discussed above, ‘space’ in science is completely different. From the point of the universe, ‘Space’ begins where the earth’s atmosphere ends. So another question arises that “What are the dimensions of space?”(dimension is a very important term to understand something in science) Well till 25 November 1915(Publication of General Relativity)space was believed to be a 3-dimensional:

1. Length
2. Breath
3. Height

But After a revolutionary work by Albert Einstein, the main geometry of space changed. So let’s focus on that. According to the general relativity, Space it treated as a 3-dimensional fabric of space and time. In fact, TIME is considered as the 4th dimension of space which is 3-dimensionally interwoven with other 3 dimensions(Length, Breath and Height) of space just like a cloth/fabric. The above image clearly depicts the basic 3 dimensions. Time is not seen as a physical dimension, as it is not.!!!! (Time as a physical dimension ) This instead accordingly to general relativity time is an abstract as a result of the curvature of space by a mass.

Yes, clearly means that more mass will bend more amount of space. Hence light, which is made up of massless photons will never bend space so will not experience time!

Talking about curvature, any mass will curve or bend the fabric of space… The famous Einstein field equations (EFE) gives the prices information about the curvature of space-time: Where:

1. Rμν is the Ricci curvature tensor,
2. R is the scalar curvature,
3. gμν is the metric tensor,
4.  Λ is the cosmological constant,
5. G is Newton’s gravitational constant,
6. c is the speed of light in vacuum,
7.  and Tμν is the stress–energy tensor.

Λ –  Cosmological constant was later considered as “not needed”

That’s all for this blog. Will write more on SPACE, TIME and GRAVITY in detail in my next blog. I will also write more in detail about the failure of general relativity and quantum model of space in my next blogs. Thank You!

Write or contact me for any query or edits.

-AS