0
The color spectrum can help astronomers tell if the star is moving closer or away from the earth by using dopler effect. If the color is shifted to the red part of the specturm (over the course of many observations) it means it is moving away. If the color is shifted to the blue or violet part it is moving closer. The same thing happens when you hear a siren go by; as it gets closer it gets louder than fades away the further away get gets. The color spectrum call also tell the astronomer what elements are present in the star. Each element has a unique color signture like a fingerprint. For the purposes of my answer, I will assume that you mean the spectrum of the light that the particular star under consideration is emitting. The spectrum of the starlight is separated into its different colors, or wavelengths, with a spectrometer, which uses a prism or diffraction grating to refract (or diffract) the light into different directions depending on the wavelength. You use photographic film or electronic detectors to measure the intensity of the light at each wavelength.
Recognize that the measured spectrum extends far beyond the visible colors which our eyes can detect. The visible spectrum is typically defined as covering wavelengths from 400 nanometers (blue) to 700 nm (red). Wavelengths shorter than 400 nm are the ultraviolet (then the extreme ultraviolet, then soft X-rays, 'regular' X-rays, etc.) Wavelengths longer than 700 nm are the infrared (then the far infrared, then microwaves, etc.)
A second important aspect of the star's spectrum that you need to know is the spectral shape, which is the graph of energy density vs. wavelength. A good illustration of this is shown on http://en.wikipedia.org/wiki/Planck%27s_law
There are several ways that the spectrum can be used. First off, if you look at the Wikipedia illustration, you see that the spectrum has a different shape for different temperatures. This allows you to tell what the surface temperature of the star is, which can give a good indication of the type of star (white dwarf, red giant, etc).
Second, if you look closely at the spectrum, you see there are wavelength that are very dim or missing entirely. They are very dim because that wavelength is absorbed by a particular atom in the star's outer atmosphere. (Or by dust and molecules that are between us and the star.) Every atom has its own set of wavelengths that it absorbs, so the set of absorption lines (as they are called) lets you figure out what atoms are present in the outer atmosphere. Hydrogen and helium are common. When you start seeing heavier materials, like carbon, sodium or silicon, then you know the star is old and nearing the end of its life.
Third, you can tell how far away the star is from the earth. Because the universe is expanding, all the stars (except a few that are close to us) are moving away from us. The further away they are, the faster they are moving away. This is known as "Hubble's Law", after Edwin Hubble who published it in 1929. (For more on this, see the Wikipedia article at http://en.wikipedia.org/wiki/Hubble%27s_law.)
One of the results of Einstein's theory of (Special) Relativity is that an object that emits light and is moving away from you looks redder (longer wavelengths) than the same object would if it were not moving. (This is called the Doppler shift, or red shift.) The amount of the shift depends upon the speed at which the object is moving. Once you have measured the spectrum, you can determine how much the spectrum is red-shifted, which tells you how fast the star is moving, which in turn tells how far away the star is.
-Dr.RSJameson 26-Feb-2008
The absorption lines in a star's spectrum tell us many things about the star, including its chemical composition (from which lines appear) and its speed toward or away from us (from the Doppler shift of those lines).
The emission spectra can tell us the atoms of a star and the atoms tell us what the star is made of
By studying the lines on the spectrum emitted by a star, scientists can determine what elements a star is composed of.
For this purpose, astronomers would analyze the starlight's spectrum.
Each element leaves a characteristic "signature" in the spectrum - lines at certain places of the spectrum indicate a certain element.
Add your answer:
Earn +20 pts
What makes the astronomers believe that hydrogen considered the primordial element in the universe?
Astronomers believe that hydrogen is the primordial element in the universe because it is the most abundant element and simple in structure. Hydrogen was the first element formed after the Big Bang and is a key component in the formation of stars and galaxies. Observations of the cosmic microwave background radiation also support the idea that hydrogen is the oldest element in the universe.
What element is present in Maltase but not in maltose?
Enzymes.
The amount of an element present does not affect the elments what?
The amount of an element present does not affect the element's identity. Each element is defined by the number of protons in its nucleus, known as its atomic number. This remains constant regardless of the quantity of the element present.
MERCURY IS so dense astronomers believe its has a high concentration of what element?
Astronomers believe Mercury has a high concentration of iron because it is one of the densest planets in our solar system, suggesting a significant amount of heavy elements.
If an element has 3 isotopes with known natural abundance percentages what other information is needed to find the average atomic mass of the element?
You still need to know the number of protons present in order to find the atomic mass.
How do astronomers know that hydrogen is present in almost every star in the universe?
Astronomers use spectroscopy to analyze the light emitted by stars. By studying the absorption lines in a star's spectrum, astronomers can identify the elements present in its composition. Since hydrogen leaves a distinct signature in these absorption lines, scientists have found that hydrogen is the most abundant element in stars, including our Sun.
Where can you get a list of famous and not so famous astronomers and astronauts of the past and present?
From Encyclopedia we can get a list of famous & not famous astronomers & astronauts of the past & present.
Why measurement are needed?
To know the quantity of matter present in the element or a thing
What can a stars spectrum can tell astronomers?
What makes up the star or element.
How do you know if it is an element?
Elements are present in the periodic table. For example Copper (Cu) is an element but copper sulphate CuSO4 is a compound.... Elements present in copper sulpahte are Copper (Cu),Sulphur (S) and Oxygen (O).
How can astronomers tell what a distant object is made of?
Astronomers can determine the composition of a distant object by analyzing its spectrum of light. Each element or molecule absorbs and emits light at specific wavelengths, leaving unique signatures in the spectrum. By comparing these signatures to known patterns, astronomers can identify the elements and compounds present in the object.
What element in earths atmosphere was not present in the far past but is present now?
The element "Oxygen".
Do astronomers know how to build?
Some astronomers are likely to be good at DIY, but most would probably get a contractor in.
What element is present in ferric chloride?
Iron (Fe) is the element present in ferric chloride.
How do astronomers know the black hole exist?
Astronomers know because they have studied star patterns and placements and know when there has been a change between where there is a black hole and where there isn't one.
How do scientists know the composition of stars?
Mostly by spectrographic observation. Every distinct element radiates exact and specific frequencies of light. By taking a tiny sample of the element and heating it to "glowing hot", we can measure the spectrum of the light that this element gives off. This is how a spectrometer works. In a star, the elements are already at thousands of degrees, so all astronomers need to do is to analyze the spectrum; most stars have spectra that are as distinct as fingerprints to people. We can determine what elements are present, and in what proportions, with considerable accuracy.
What is 1 element which is present in a phospholipid and not present in chitin?
Choline is an element present in phospholipids but not in chitin.
