<P> There are three main types of nebula : absorption , reflection , and emission nebulae . Absorption ( or dark ) nebulae are made of dust and gas in such quantities that they obscure the starlight behind them , making photometry difficult . Reflection nebulae , as their name suggest , reflect the light of nearby stars . Their spectra are the same as the stars surrounding them , though the light is bluer ; shorter wavelengths scatter better than longer wavelengths . Emission nebulae emit light at specific wavelengths depending on their chemical composition . </P>
<P> There are three main types of nebula : absorption , reflection , and emission nebulae . Absorption ( or dark ) nebulae are made of dust and gas in such quantities that they obscure the starlight behind them , making photometry difficult . Reflection nebulae , as their name suggest , reflect the light of nearby stars . Their spectra are the same as the stars surrounding them , though the light is bluer ; shorter wavelengths scatter better than longer wavelengths . Emission nebulae emit light at specific wavelengths depending on their chemical composition . </P>
which astronomical bodies emit light in the visible spectrum
which astronomical bodies emit light in the visible spectrum
Emission nebulae
Emission nebulae