Astronomy

1. Astronomy By Sariaya Phillips

2. Research Question • Are all galaxies alike in the universe? • *I investigated this question based upon the color variations of stars in galaxies. • My new question became: Are all the galaxies in our sample the same color?

3. Methodology • Methods used to figuring out the answer - I used the SDSS sky server website and collected data about galaxies in space. • Specific information that needed to be found consisted of the following: (RA, DEC) , petraRad_r, modelMag_r, Z by spectra, Z error, Classification type, the U and R, and the U-R calculations. • I spilt up the U-R measurements into bins of 0.2 and counted the galaxies in each of the bins, making a histogram of the data collected.

4. Data • *If the U-R number is higher then 2.2 the galaxy is redder and if the number is lower then 2.2 then it is bluer. • *2.2 is the dividing line in galaxy color between red and blue.

5. Analysis • I found out that not all the galaxy colors are the same in the class sample of 269. I also found out that there were more red galaxies than blue.

6. Conclusion • In conclusion based upon the data collected not all galaxies are the same in the universe. Each galaxy contains different colors of stars. Some have a lot more red and less blue, 169 red galaxies compared to 105 blue galaxies to be exact from the class sample. There are more red galaxies/stars, because they are cooler which means they live longer. This is like a marathon runner versus a sprinter. A sprinter is similar to a blue star and a distance runner is similar to a red star. A sprinter burns energy faster like a blue star and the distance runner goes through the energy slower such as a red star. As a result, because blue stars die faster you are left with more red stars so the galaxy looks more red.