What is the difference between blueshift and redshift

You're probably more familiar with Redshift as its talked about quite a bit. When something is moving away from something else, the light that is emitted is predominantly at the red end of the spectrum. Red light wavelengths tend to be more stretched out the further you are from the object. Blue light wavelengths tend to be closer together. Blueshift light tends to be emitted from objects that are moving closer. By looking at the blue and red shift, we can determine whether the object is coming closer to us such as in the case of the Andromeda galaxy or moving away from us.

By looking at the spectrum of the objects light, it is also possible to determine how far away the object is by the stretched nature of the spectrum. The further away, the more red the lights spectrum has.

In the case of the Andromeda Galaxy, it has been discovered that it moving closer to us, at about 75 miles per second which may seem fast but due to the sheer distance between our galaxy and the Andromeda Galaxy means they won't collide for another four billion years so we are safe. Scientists use spectrographs to look at the colour spectrum of the light from the star to determine the characteristics. When the source and the observer moves away or towards relatively, the wave fronts from the source either get separated or cramped together.

This results in a change, in the rate of wave fronts received by the observer than the rate it was emitted by the source. Doppler Effect can be observed in every wave, whether electromagnetic or mechanical. When the source and the observer are moving relatively towards each other, then the apparent frequency is higher than the source frequency. If the source and the observer are receding relative to each other, then the apparent frequency is lower than the source frequency.

Since frequency change is related to the motion of the observer and the source, it can be used to deduce the motion. Assume the observer is stationary. If the apparent frequency is higher than the source frequency, it can be deduced that the source is moving towards the observer.

Most discoveries have been of extremely massive planets, but recently a planet with a mass only a few times that of Earth was detected. It is close to a dim reddish star and the temperature of its surface is estimated to be tens of degrees below the freezing point of water. If the planet has greenhouse warming it might be able to sustain life. Many features only work on your mobile device.

If you like what you see, we hope you will consider buying. Get the App.