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How can astronomers tell if a star is approaching or receding from earth?
Wiki User
∙ 12y ago
The relative motion between the observer and wave source causes an apparent change in frequency which is known as Doppler Effect. On combination with identification of spectra, it can also be used to find if the start is moving away or towards the earth, When there is shift in lines of spectra towards the red end of visible spectrum the star is said to be travelling away from the earth.
Wiki User
∙ 9y ago
Wiki User
∙ 12y agoThe Doppler effect takes affect on waves. In sound waves, it causes sounds to perceived as higher when the source is approaching, and lower when it is receding. With light, it is similar. When the source is moving towards us, the waves are pushed closer together, causing the light to appear bluer than usual. This is called blue shifting. When the source is receding, the waves become more separated. This causes the light to appear redder in what is called red shifting.
Wiki User
∙ 13y agoWe can use spectroscopes to measure the precise frequencies of the light that we see coming from those stars. If the stars are moving toward us, we will see a "blue-shifted", or higher frequency, spectrum, and if we see a lower-frequency "red-shifted" spectrum, we can be fairly sure that that star is moving away.
Wiki User
∙ 12y agoBy looking at absorption and emission lines in the light spectra from stars and galaxies.
With light from a stationary source these line always appear in the same place on the spectrum.
Should the source be moving away the lines are shifted to the end of the spectrum with longer wave lengths, which is towards the red end of the spectrum. Hence the phrase 'red shift'. If the source is approaching the opposite is true.
Very few show a 'blue shift', only those objects in the immediate local cluster.
From this astronomers have concluded that the universe as a whole is expanding.
Wiki User
∙ 12y agoThey use the Doppler effect and light. If the light on the spectromerter is towards red light,because red light has a lower frequency and higher wavelength. The further the galaxy.
Wiki User
∙ 11y agoIts slightly blue if moving close or red if moving away. Due to Doppler effect
Wiki User
∙ 15y agoAnywhere westward.
Wiki User
∙ 14y agoStars don't move, Earth does.
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Which star do the earth and other planets in the solar system orbit?
* main sequence The sun. (sometimes called 'Solaris' by astronomers)
The red shift of visible light waves that is observed by astronomers on earth is used to determine the?
The speed of relative retreat of the star.
How do astronomers measure stellar luminosity?
The reference that astronomers use to compare the luminosity of other stars is the sun's luminosity. The luminosity is denoted in multiples of the sun's luminosity. For example, the luminosity of the star Sirius is 25 times the luminosity of the sun.
If we observe a Doppler blue shift from a star the star must be a?
In that case, the star must be approaching us.
What do you call a star that appears to pulsate?
A star that pulsates is known as a variable star.
What did the astronomers use to discover that the star Sirius was moving away from Earth?
A freaking telescope
What does the Doppler affect tell astronomers about a star?
The star attracts the planet; the planet attracts the star. As a result of the latter, the star changes position. If this change is such that the star moves away from us during one part of the planet's orbit, and towards us at another (or more generally, the star's speed towards us, or away from us, changes slightly), then this can be detected as a Doppler shift.
How can astronomers determine whether a star is moving toward or a way from earth?
They can do so by examining the light from the star. Doppler shift can indicate this
What two things must an astronomers find out in order to calculate a star's absolute brightness?
It's distance from Earth and the star's actual brightness
Which star do the earth and other planets in the solar system orbit?
* main sequence The sun. (sometimes called 'Solaris' by astronomers)
The red shift of visible light waves that is observed by astronomers on earth is used to determine the?
The speed of relative retreat of the star.
How did astronomers discover that the star Sirius was moving away from earth?
They craped in the toilet and Looked up in the sky and said sh!t Sirius is moving away from earth.
How do astronomers measure stellar luminosity?
The reference that astronomers use to compare the luminosity of other stars is the sun's luminosity. The luminosity is denoted in multiples of the sun's luminosity. For example, the luminosity of the star Sirius is 25 times the luminosity of the sun.
What can a stars spectrum tell astronomers about a star?
What elements the star is made of.
Is the sun a white star?
Strangely enough even scientists can't always agree on exactly what colour the Sun appears to observers on Earth. However it is classified officially by astronomers as a yellow star.
What is the apparent brightness of the stars?
Astronomers define star brightness in terms of apparent magnitude how bright the star appears from Earth and absolute magnitude how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
What are the instruments used by the astronomers to study star?
telescopes
