in what specific way does light from distant stars and galaxies tell astronomers that atoms throughout the universe have the same properties as those on earth?
Except for doppler shifts due to relative motion of the galaxies, the spectroscopic wavelengths of atomic species seen in the spectra are the same.
Light from distant stars and galaxies provides valuable information to astronomers about the properties of atoms throughout the universe. The specific way in which it tells us that atoms have the same properties as those on Earth is through the phenomenon called spectroscopy.
Spectroscopy is the study of the interaction between matter and electromagnetic radiation, such as light. When light from a distant source, such as a star or a galaxy, reaches our telescopes, it carries valuable information encoded within its spectrum.
A spectrum is a range of electromagnetic radiation composed of different wavelengths or colors. By analyzing the light spectrum, astronomers can determine the composition of the object that emitted the light. This is because atoms absorb and emit light at specific wavelengths, creating characteristic patterns in the spectrum.
To study the properties of atoms, astronomers look for specific features in the spectrum, such as absorption lines. These absorption lines occur when atoms in the object's atmosphere or starlight interact with the light, absorbing specific wavelengths that are characteristic of certain elements. These lines are like unique "fingerprints" that reveal the presence and identity of elements in the object.
The significance of these absorption lines lies in the fact that they match the properties of known elements on Earth. Scientists have extensively studied the behavior of atoms under various conditions in laboratories on Earth, allowing them to identify the atoms present in distant objects based on the absorption lines in their spectra.
By comparing the absorption lines in the spectrum of a distant star or galaxy to those of elements on Earth, astronomers can confidently conclude that the atoms throughout the universe have the same properties as those on Earth. This supports the fundamental idea that the laws of physics and chemistry that govern the behavior of matter are universally applicable.