Is the expansion of the Universe the same everywhere?

Yet there is no centre to the expansion; it is the same everywhere. The Big Bang should not be visualised as an ordinary explosion. The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell.

Is the space within our solar system expanding?

Solar systems do not expand despite existing in an expanding universe because of the binding force of gravity. In fact, even galaxies have enough gravity to withstand expansion.

Is the universe the same in all directions?

There are more stars toward the center of the Milky Way than there are in other directions. But across millions and billions of light-years, galaxies cluster evenly in all directions, and everything starts to look the same. In astronomy, we say the universe is homogeneous and isotropic.

What is the definition of the universe expanding?

It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand “into” anything and does not require space to exist “outside” it. Technically, neither space nor objects in space move. Instead it is the metric governing the size and geometry of spacetime itself that changes in scale.

Why does the universe have underdense regions?

It has overdense regions, like planets, stars, galaxies and clusters of galaxies. It has underdense regions, like great cosmic voids where there are virtually no massive objects present at all. The reason for this is that there are other physical phenomena at play besides the Universe’s expansion.

What causes the big competition in the universe?

The big competition occurs on the largest scales of all — on the scale of the entire Universe — between the Universe’s expansion and the gravitational attraction of all the matter and energy present within it. On the largest scales, the Universe expands and galaxies recede from each other. But on smaller [+]

How does the expansion of the universe relate to general relativity?

As an effect of general relativity, the expansion of the universe is different from the expansions and explosions seen in daily life. It is a property of the universe as a whole and occurs throughout the universe, rather than happening just to one part of the universe.