In the article, Dual Black Holes Spinning in a Cosmic Dance – Complete with Disco Ball, by Nancy Atkinson from universetoday.com, she discusses how astronomers recently discovered over 30 pairs of black holes merging together. The movement she described the black holes was basically dancing since the pair of black holes would circle each other. And we can tell they are circling each other by using the light captured from the black holes and determined either if the light is being blue-shifted or red-shifted. Blue meaning it’s getting closer to us and Red meaning it’s getting further away from us.
After reading this article, I’ve thought that reading of Doppler shifts only associated with Stars and not Black holes. Also in the reading, They discussed how Isaac Newton predicted the movement of black holes merging together, which is really surprising how he knew that with out the equipment we have today.
This article relates to our conceptual objective, “I can explain how astronomers use light to determine the chemical composition, the speed and direction of an astronomical object’s motion”, by implementing the Doppler shifts we learned about stars and associated it with black holes and discovering merging black holes. In class, we worked on pages 75-80 on our lecture tutorial about Doppler shifts. This activity showed that stars moving toward us have a shorter wavelength and that stars that are moving away from us have longer wavelengths. On the light spectra, if the star is moving away from us, the absorption lines shift toward the red side (Red-Shifted) and if the star is moving towards us, the absorption lines shift towards the blue side (Blue-Shifted). The bigger the shift, the faster the object is moving. The way we can tell the chemical composition of most stars, is the fact that chemicals like hydrogen emit a specific wavelength, so its possible to detect this from far away distances. Hydrogen and Helium are the basic composition of most stars.