Why do stars stop growing?
In medium size stars, after the nuclear fusion has used up all the fuel it has, gravity will pull the remaining material closer together. The star will shrink. In fact, it may get to be only a few hundred kilometers wide! The star is then called a “white dwarf”.
What keeps the star from expanding out into space indefinitely?
Stars are fueled by the nuclear fusion of hydrogen to form helium deep in their interiors. The outflow of energy from the central regions of the star provides the pressure necessary to keep the star from collapsing under its own weight, and the energy by which it shines.
How do galaxies keep on forming stars?
Galaxies are very massive, too, so their gravity is strong. When you crowd them together, the attraction can be so strong that two galaxies latch on to each other and don’t let go. Eventually they merge, forming a single giant city of stars.
Do all stars eventually explode?
Luckily for us, not all stars explode and then die. When stars age, they change from a dwarf star (our Sun is actually currently a dwarf star) into a giant star. If a star is big enough it can then explode in what we call a “core-collapse supernova”. So, we’re safe from the Sun exploding.
What is the building block of galaxies?
“Star clusters are often considered as building blocks of galaxies. There are two main groups of star clusters: OCs and globular clusters (GCs). OCs are generally young objects, up to a few tens of millions of years old.
Is the Big Rip real?
Overview. The truth of the hypothesis relies on the type of dark energy present in our universe. If −1 < w < 0, the expansion of the universe tends to accelerate, but the dark energy tends to dissipate over time, and the Big Rip does not happen.
What keeps a galaxy together?
What holds galaxies together? Gravity. All of the stars of a galaxy are all attracted to each other. There is also a large amount of matter that has never been seen (called “dark matter”) that helps keep galaxies together.
What causes galaxies to form?
Galaxies are thought to begin as small clouds of stars and dust swirling through space. As other clouds get close, gravity sends these objects careening into one another and knits them into larger spinning packs.