Question

How long can a nebula live?

Answer 1

Hint: A nebula is a massive cloud of gas and dust in space. Some nebulae (multiple nebulae) are formed by the gas and dust ejected by the explosion of a dying star, such as a supernova. Other nebulae are areas where new stars are forming.

Complete answer:
A nebula is a massive cloud of gas and dust in space. Some nebulae (multiple nebulae) are formed by the gas and dust ejected by the explosion of a dying star, such as a supernova. Other nebulae are areas where new stars are forming. As a result, some nebulae are referred to as "star nurseries."
Nebulae are composed of dust and gases, the majority of which are hydrogen and helium. The dust and gases in a nebula are widely dispersed, but gravity can gradually pull clumps of dust and gas together. As these clumps grow in size, their gravitational pull grows stronger.
The clump of dust and gas eventually becomes so large that it collapses due to its own gravity. The collapse causes the material in the cloud's core to heat up, and this hot core is the birthplace of a star.
Nebulae are found in the space between stars, which is also known as interstellar space. The Helix Nebula is the closest known nebula to Earth. It's the remains of a dying star, possibly the Sun. It's about 700 light-years away from Earth. That means that even if you could travel at the speed of light, you'd still need 700 years to get there!
The nebula takes 10 million years to collapse for a star the size of the sun.It takes less time for larger stars, as little as 100,000 years. Smaller stars may require far more than 10 million years.

Note: Astronomers use very powerful telescopes to photograph distant nebulae. Many images of distant nebulae have been captured by space telescopes such as NASA's Spitzer Space Telescope and Hubble Space Telescope.