We can even speculate that stars are condensed from interstellar gas. Interstellar dust is a very small solid substance, which is composed of carbides, oxides and so on. A cubic centimeter has 10- 100 atoms (in fact, this is much lower than the vacuum in the laboratory). Planetary nebulae look a bit like smoke rings, with an empty center and usually a very bright star. Stars constantly release matter and form nebulae. Planetary nebulae are the product of the late evolution of stars. The most famous are the Aquarius spiral nebula and the Lyra ring nebula.
Physically, it can be divided into: huge, thin, amorphous diffuse nebula (irregular shape, maximum boundary diameter of several tens of light years, weight of about 10 suns, density of10/00 atoms /cm3), and planetary nebula with a high-temperature core star in the center of bright ring (planetary nebula is composed of a light-weight star)
According to the luminous characteristics, it can be divided into the following categories: emission nebula excited by high-temperature shining stars at or near the center (earlier than B 1), reflection nebula radiated by low-temperature shining stars (later than B 1), and dark nebula partially or completely blocking the background stars (such as Orion's head). The first two are collectively called bright nebulae, that is, nebulae with changing brightness, which are called variable nebulae. The only difference between reflection nebula and dark nebula lies in the relative positions of photographic star, nebula and observer.
Nebula (with hyphen or, meaning pl. Cloud) is an interstellar cloud composed of dust, hydrogen, helium and other ionized gases. Originally a general term in astronomy, it refers to any astronomical scattering object.
Including galaxies outside the Milky Way (some past usages are retained, such as EdwinHab still using the name before EdwinHab, namely Andromeda Nebula). Usually nebulae are also areas where stars form, such as eagle nebulae. This nebula depicts NASA's most famous image: the pillar of creation. The gas, dust and other substances formed in this area are squeezed together, forming a huge mass, attracting more substances, and finally being large enough to form stars. We know that the remaining matter can also form planets and other planetary bodies.
Nebula is a cloud-like object, which is composed of gas and dust in interstellar space. The density of matter in the universe is very low, and if measured by the standards on earth, some places are vacuum. However, this nebula is very huge, usually dozens of light-years away from Fiona Fang. Therefore, nebulae are usually much heavier than the sun.
The shape of this nebula is very complicated. Stars are related to nebulae. The gas in the nebula will become a part of the nebula, and the matter in the nebula will be compressed into stars by gravity. Nebulae and stars can be transformed into each other in some cases. Objects that look like clouds, all the star-like gas and dust clouds in the galaxy are outside the solar system.
To sum up, if the stars formed in the nebula are of high mass and density, they will form stars. Some "scraps" or stars with insufficient quality left after the stars are produced form stars. So you should understand how stars and planets are formed. In other words, the position of the solar system must have been a beautiful nebula before.