Packet 1: Bonus 3
In the presence of an isotropic, unpolarized, stochastic background of these phenomena, pulsar timing arrays have residuals whose correlation follows the Hellings-Downs curve. For 10 points each:
[10m] What phenomena are causing the orbital decay of the Hulse-Taylor binary pulsar?
ANSWER: gravitational waves [or gravitational radiation; or GWs; accept stochastic gravitational wave background or SGWb; prompt on waves; reject “gravity waves”]
[10h] Pulsar timing arrays typically use this class of pulsars due to their stable periods. Pulsars in this class are formed by a “recycling” mechanism in which they are spun up by accretion from a companion star.
ANSWER: millisecond pulsars [accept MSPs]
[10e] In 1992, the first confirmed detection of these objects studied timing variations in the millisecond pulsar Lich. The Kepler space telescope used the transit method to detect these objects.
ANSWER: exoplanets [or extrasolar planets; accept descriptions of planets outside the solar system; prompt on planets]
<LK, Other Science (Astronomy)> | NAFTA-Packet-1
| Heard | PPB | E % | M % | H % |
|---|---|---|---|---|
| 26 | 16.92 | 100% | 50% | 19% |
Conversion
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total | Parts |
|---|---|---|---|---|---|---|
| JHU | Contessa Dora | 10 | 10 | 10 | 30 | MHE |
| Maryland F♯ A♯ ∞ | Mike and Psmith | 10 | 0 | 10 | 20 | ME |
| Munir Siddiqui Fan Club | Rosslyn Academic Team | 0 | 10 | 10 | 20 | HE |
| Penn State | Catholic University A | 0 | 0 | 10 | 10 | E |
| UNC Charity | The Imgur Link | 0 | 0 | 10 | 10 | E |
Summary
| Tournament | Edition | Match | Heard | PPB | E % | M % | H % |
|---|---|---|---|---|---|---|---|
| 2026 NAFTA at Stanford | 01/17/2026 | ✕ | 4 | 17.50 | 100% | 50% | 25% |
| 2026 NAFTA at UBC | 01/17/2026 | ✕ | 2 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA Online | 02/14/2026 | ✕ | 4 | 25.00 | 100% | 75% | 75% |
| 2026 NAFTA at Vanderbilt | 02/14/2026 | ✕ | 3 | 13.33 | 100% | 33% | 0% |
| 2025 NAFTA at Toronto | 09/13/2025 | ✓ | 4 | 15.00 | 100% | 50% | 0% |
| 2025 NAFTA at Maryland | 09/27/2025 | ✓ | 5 | 18.00 | 100% | 40% | 40% |
| 2025 NAFTA at Harvard | 10/04/2025 | ✓ | 3 | 13.33 | 100% | 33% | 0% |
| 2025 NAFTA at Oxford | 10/11/2025 | ✓ | 3 | 10.00 | 100% | 0% | 0% |
| 2025 NAFTA at Chicago | 11/08/2025 | ✓ | 6 | 20.00 | 100% | 67% | 33% |
| 2025 NAFTA at Columbia | 11/08/2025 | ✓ | 5 | 20.00 | 100% | 80% | 20% |
| 2025 NAFTA at Richmond | 12/20/2025 | ✕ | 2 | 10.00 | 100% | 0% | 0% |