Clockwork in the Cosmos: Orbital Period Patterns Quiz

If a planet follows a closed path around a star, and if that motion is constant and predictable, then the time interval between the start and finish of one revolution is defined as the orbital period.

If one dip is observed, it could be a random event or noise. If two dips occur, an interval is suggested. If a third dip occurs at the exact same predicted interval, then the pattern is established and the periodic signal is verified.

If a signal is very weak compared to the noise, and if that signal is perfectly periodic, then cutting the light curve into segments of one period length and stacking them (folding) will cause the true signal to add up while random noise cancels out.

If a planet is in a stable orbit, it must pass the same point regularly. If a comet is on a one-time trajectory, it will not return. Therefore, the presence of a repeating cycle identifies the object as an orbiting body.

If we want to see a dip, the planet must pass between us and the star (alignment). If it is an orbit, the timing must be regular. If the physics of the orbit are stable, then each crossing (duration) should take the same amount of time.

If a single planet is responsible for the dips, and if the star's surface brightness remains relatively uniform, then the same amount of surface area will be blocked during every transit; thus, the percentage of light lost (depth) must remain constant.

If the period (P) is 10 days, the transits occur at T=0, T=10, T=20, T=30, and T=40. If we count the first transit as the starting point (T=0), then the 5th transit is at the end of the 4th interval; thus, 4 * 10 = 40 days later.

If the law states that the square of the period (P^2) is proportional to the cube of the distance (a^3), and if we measure P from the light curve, then we can algebraically solve for the average distance (a).

If a planet takes 10 years to orbit its star, and if a scientist only observes the star for 5 years, then it is impossible to see the repeat needed for confirmation; therefore, long periods require extended mission durations.

If multiple planets exist in a system, their mutual gravity can tug on each other, causing a planet to arrive at its transit point slightly early or late; therefore, a non-perfectly repeating timing indicates the presence of additional masses.

If a planet is close to its star (Hot Jupiter), its year is very short (often days). If it transits every few days, then astronomers can collect many repeats in a short time, making the signal very easy to distinguish from noise.

If the intervals between identical events are constant, then the behavior is defined as periodic.

If the data contains two distinct, overlapping periodicities with different depths and timings, and if each is consistent with a planetary transit, then the system must contain multiple planets.

If the orbit isn't aligned, it won't block light. If the mission ends before a repeat happens, the period isn't confirmed. If the planet is tiny, the dip is too small to see; therefore, all these factors limit detection.

If a period defines the gap between events, then scientists need a reference point to predict future events; if that reference point is the timestamp of the first dip, then it is called the epoch.

If an orbit is elliptical, the planet's speed varies throughout its path. If the orientation of that ellipse shifts over time, then the planet will cross the star at different speeds, causing the duration of the dip to vary slightly.

If the period matches Earth's exactly, and if the host star is identical to the Sun, then the distance must equal Earth's distance, which is defined as 1 Astronomical Unit (AU).

If two stars orbit each other and one passes in front of the other, they create a repeating dip in light. If those stars are small or the dip is shallow, it can look exactly like a planetary transit signal.

If we are looking for patterns over time, then time must be the independent variable (x-axis). If we are measuring the dip in light, then brightness must be the dependent variable (y-axis).

If a period is very short (1 day), then P is small. If P^2 = a^3, and P is small, then a (the distance) must also be very small; therefore, the planet is orbiting very close to its star.