In general there are two type of black holes:
1. Stellar mass black holes:- when a massive star dies
2. Supermassive black holes:- at the center of galaxies.
Now it has been proposed that black holes of infinitesimal size also exit, moreover, we can produce them at particle accelerators...
I do not understand what do you mean. I am just saying that at some fixed time one needs a fourth spatial dimension to have (visulaize) the curvature of "space".
Note that time comes in picture when we talk about the dynamics. One can always study the universe at some fixed time.
Most of...
This all is fine
I do not know why you are involving time here. Curvature of space is a static property i.e., we are talking the curvature of "space" at some fixed time. Note that in
cosmolgy "k" reprsents this.
By the way all physical concepts are just aids to understand the universe...
This is purely a spatial dimension, indistinguishable from other three spatial dimensions. Our world corresponds to a three surface on which the coordinates corresponding to this fourth dimension are constant. You can look about it in any cosmology textbook (Peebles, Physical cosmology, page 60)...
This is totally wrong. The fourth dimension which I am talking about is not time. If you do not mind please look
at the derivation of FRW line element in any textbook (Peebles physical cosmology etc). There we start with the
discussion of embiddeing a three dimensional space in a four...
Excatly ! in order to feel or to understand where our
three dimensional space in expanding into we have to
go away from it along the fourth dimension which seems
to be impossible.
Dear Friends,
As most of you are agreed that there are degenracies in
scientific explanations. These are mainly due to "observation selection bias". I think most us will agree
that scientific explanations are not the final truths, they are just models, they give one of the possible...
If it is not like the expansion we are familer with then
why we should call it expansion at all ? since it create unnecesary confusions.
It expands into a 3-dimensional space.I know it is not
always that a 'n' dimensional space requires 'n+1' dimensional space, sometime an 'n' dimensional...
These problems always come when we make a sentence without understanding it completely.
This is interesting that gravity travels faster than the
speed of light. Because we see that there sits a supermassive black holes that affect the surrounding material by gravity and this is possible if...
There are many qusetions in science & cosmology which
have degerate answers some of them are as follows:
1. In the presence of matter space get curved so
massive particles as well as light photons do not move
along stright line. Now one could always assume that
photons also carry...
hi,
one of my friends will be visiting ictp (italy) very soon, she learned from somebody that water is scarce and
expensive there (compared to indian standard) is this true ?
I will be thankful to your answer
by
Plese look somewhere else this is an important propery
of grvaitational intercation unlike to other fundmental
intercations gravity shows this property.
expansion
We would not be knowing about the expansion of the universe if everything were expanding, however, we know that bound objects do not expand so we can feel the expansion of the universe. My question is that since gravity is scale free then how this scale comes, below
which objects...