Question
This element is consumed in the CNO cycle and proton-proton chain. For 10 points each:
[10e] Name this most abundant element in the universe. A heavier isotope of this element is deuterium.
ANSWER: hydrogen [or H]
[10h] Transitions in the hyperfine structure of hydrogen create this spectral line, named for its wavelength. Radio waves in this feature are used to observe properties of galaxies.
ANSWER: 21 centimeter line [or 21 cm; reject equivalents of “21 centimeters”, such as “0.21 meters”]
[10m] Radio waves in the 21 centimeter line, unlike visible light, can also pass through this substance undeterred. The interstellar medium consists of gas, cosmic rays, and this substance.
ANSWER: cosmic dust [or extraterrestrial dust or interstellar dust or space dust or star dust]
<Other Science>
Summary
| 2024 ACF Fall at Cornell | fall | Y | 7 | 14.29 | 100% | 43% | 0% |
| 2024 ACF Fall at Ohio State | fall | Y | 7 | 17.14 | 100% | 71% | 0% |
| 2024 ACF Fall at Washington | fall | Y | 1 | 20.00 | 100% | 100% | 0% |
| 2024 ACF Fall at Georgia | fall | Y | 10 | 18.00 | 100% | 60% | 20% |
| 2024 ACF Fall at North Carolina | fall | Y | 7 | 14.29 | 100% | 43% | 0% |
| 2024 ACF Fall at Claremont Colleges | fall | Y | 5 | 12.00 | 100% | 20% | 0% |
| 2024 ACF Fall at Rutgers | fall | Y | 7 | 18.57 | 100% | 71% | 14% |
| 2024 ACF Fall at Illinois | fall | Y | 9 | 12.22 | 89% | 33% | 0% |
Data
| Chicago A | WashU A | 10 | 0 | 10 | 20 |
| Chicago B | Notre Dame C | 10 | 0 | 0 | 10 |
| Illinois D | Notre Dame B | 10 | 0 | 0 | 10 |
| WashU B | Indiana | 10 | 0 | 0 | 10 |
| Iowa A | Purdue A | 10 | 0 | 10 | 20 |
| Northwestern B | Illinois C | 10 | 0 | 0 | 10 |
| Northwestern A | Notre Dame A | 10 | 0 | 10 | 20 |
| Purdue B | Iowa B | 10 | 0 | 0 | 10 |
| SIUE | Purdue C | 0 | 0 | 0 | 0 |