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Question 1
How does the Lyman-alpha line help scientists to explain why galaxy EGS-zs8-1 is a significant discovery? Your answer should be a well-organized paragraph and should reference quantitative and qualitative details from throughout the entire article, as well as visual information from the photograph.
A correct answer should include the following:
- The Lyman-alpha line allows scientists to estimate the distance of an observed galaxy.
- At first, scientists didn’t know if galaxy EGS-zs8-1 was close and dim or far away and bright.
- They could see through photos from the Hubble and Spitzer telescopes that it appeared very faint.
- After using the Lyman-alpha line to determine distance, the scientists could figure out the following about the galaxy:
- The galaxy was very active.
- It was “forming stars at roughly 80 times the rate the Milky Way does today” at the time they viewed it.
- It had created “8 billion suns’ worth of mass” at the time that they were viewing it.
- It had created “more than 15 percent of the mass of the Milky Way.”
- The Lyman-alpha line also helps to estimate age, since that is linked to distance.
- This helped scientists to determine that it was “roughly 13.1 billion years old.”
- The galaxy’s age is close to the 13.8-billion-year age of the universe.
- This tells scientists they are looking at a very old galaxy similar to the beginnings of the universe.
- Without the Lyman-alpha line, scientists would not have been able to figure out any of the important details about galaxy EGS-zs8-1’s age, distance, brightness or activity level.