2535487
Ano: 2016
Disciplina: Inglês (Língua Inglesa)
Banca: FACET Concursos
Orgão: Pref. Santa Rita-PB
Disciplina: Inglês (Língua Inglesa)
Banca: FACET Concursos
Orgão: Pref. Santa Rita-PB
Provas:
Read the article below and answer the question.
What we [TO LEARN] about Pluto: Smaller moons spin sideways, and rapidly
The four small moons of Pluto turned out to be brighter and smaller than expected and spin quickly. Their axes are also tipped sideways, a configuration that defies easy explanation.
Pluto and its miniature planetary system are believed to have coalesced out of a cataclysmic collision earlier in the history of the solar system. Over time, the rotation of moons tend to become gravitationally locked so that the same side of the moon is always facing the planet. That occurred with Charon.
But the four smaller moons — Nix, Hydra, Styx and Kerberos — are tiny and (I) away. A month before the flyby, two astronomers suggested, based on years of Hubble photographs, that Nix and Hydra, appeared to be rotating chaotically, jostled by the competing gravitational pulls of Pluto and Charon. They also said that Kerberos was markedly darker than the other three.
The New Horizons photographs [TO SHOW] otherwise. None of the moons appear to be rotating chaotically, and their spin is faster than expected, not at all locked to their orbital periods, which range from 20 to 38 days. Hydra spins fastest, at once every 10 hours. Kerberos turns out not to be dark; the four small moons are all brighter and smaller than previously estimated, ranging in reflectivity between fresh concrete and fresh snow.
The rotation of the small moons are also tipped over, almost at 90-degree angles from what would be expected. “We have no idea what that means yet,” Dr. Spencer said.
One of the astronomers who reported the chaotic rotations, Mark R. Showalter of the SETI Institute in Mountain View, Calif., said that the New Horizons’ observations surprised him, and that he was working on reconciling them with what Hubble had seen.
(New York Times)
The possessives pronouns “their”, in the first paragraph, and “its” in the second paragraph, are respectively referring to:
