Which characteristics is used to classify galaxies?

Answer 1

In almost every case, whether it is an instrument actually on the planet, or a telescope looking up from the earth, scientists use some variation of an instrument called a spectrometer. Spectrometers take a signal from whatever they are looking at (whether it is a rock, or a cloud or a whole planet or a star or a galaxy or a nebula, etc.) and spread the signal out into its components. Most spectrometers work with light and are a lot like extremely good prisms; they take the light coming from some object and separate it out into its colors. This is useful because it turns out that every element on the Periodic Table only gives off light of a few certain colors.

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Answer 2

I don't know whether this counts as "proof", but the general idea is that only the interior of stars - and not all stars, just the more massive ones - is hot enough to create those elements. In the first few minutes of the Big Bang, there were also extremely high temperatures, but there was not enough time to form heavier elements.

They also do spectral analysis of the light emanating from the star, and they can see the various lines representing the various elements. Physicists also know that iron is the heavist element created in the stars from nuclear fusion because it has the highest binding energy per nucleon of all the nuclides. For more information, please see the Related Link below.

Answer 3

This is done by looking at the star's spectrum. Each element has characteristic wavelengths in which it radiates energy and which it will absorb. The spectrum enables scientists to determine which elements are present in the star.

Answer 4

From obsevations mainly. But, galaxies are made up of many other objects besides stars.

Answer 5

By examining the emission spectrum of the star to determine the elements present in that star.

Answer 6

They can analyze the light that comes from a star, getting a spectrum of it. Different elements have different characteristic lines in the spectrum.

Answer 7

Spectral lines.

Answer 8

They use a spectrometer.

Answer 9

color and size

Answer 10

The shape of the galaxy