About5 billion years and good for another 5 billion
If you mean do they come into existence and later cease to exist, the answer is; not on their own. In this sense they are like big rocks orbiting a star (sun), and as long as the sun is there they will be there. But, eventually the sun they orbit will explode and destroy them.
5 billion years
mountains* The Himalaya mountains have existed for approximately 40-50 million years.
the number would not fit in the alloted space...
gravity and radiation pressure from thermonuclear fusion.
As long as cows have been in existence, or the whole Bos primigenius species and subspecies have been in existence.
Helium is has been in existence since the beginning of the universe.
they have been in existence for 110 years since 1901.
The IUPAC has been in existence since 1919. (93 years ago.)
long time
October 1920
since 1992
they have been here forever
88 years
The saxophone was patented in 1846.
1909
1956