The Solar System - Word Search - PUZZLE #49 HARTLEY TWO - August 2025

PUZZLE #49 - HARTLEY TWO 

IN-CONTEXT WORD DEFINITIONS

Comet: Hartley 2 is a small, icy body that orbits the Sun. As it approaches the Sun, it heats up, releasing gas and dust that form a visible coma and tails, classifying it as a comet.

Periodic: Hartley 2 is a periodic comet, meaning it returns to the inner Solar System at regular intervals. Its orbital period is relatively short, approximately 6.46 years.

Hyperactive: Hartley 2 is considered a "hyperactive" comet because it releases more water than would be expected based solely on the amount of surface area illuminated by the Sun. This hyperactivity is attributed to the presence of numerous jets erupting from its surface.

Nucleus: This is the solid, icy core of Hartley 2. Images from the EPOXI mission revealed that its nucleus is small (approximately 1.2 x 1.6 kilometers or 0.75 x 1 mile), peanut-shaped, and rotating, with jets erupting from various locations.

Dust: Along with gases, dust particles are released from Hartley 2's nucleus due to the sublimation of ice. This dust contributes to the coma and forms a dust tail.

Gas: Water vapor is the primary gas released from Hartley 2's nucleus. Other gases, such as carbon dioxide and carbon monoxide, are also present, forming the comet's coma and ion (gas) tail.

Jets: Hartley 2 is characterized by numerous "jets" or streams of gas and dust erupting directly from its nucleus. These jets are responsible for the comet's hyperactivity and were a key observation made by the EPOXI mission. They often originate from specific active regions on the nucleus.

EPOXI: This is the name of a NASA extended mission that sent the Deep Impact spacecraft on a flyby of Hartley 2 in November 2010. The mission studied the comet's nucleus, coma, and jets, providing unprecedented close-up views.

Tumbling: Observations revealed that Hartley 2's nucleus was "tumbling" as it rotated. This means its axis of rotation was not stable but rather precessing and changing orientation, likely due to the asymmetrical forces exerted by its numerous jets.

Secret Word: As Hartley 2 approaches the Sun, the ice in its nucleus sublimates, creating a hazy atmosphere of gas and dust surrounding the nucleus. This atmosphere is called the coma.