By David Coppage
What’s up in astronomy? Surprises, by heavens.
Spherical sun: The sun is too close to a perfect sphere than expected theoretically, a finding “baffling” to astronomers. “Definitive” measurements by the Helioseismic and Magnetic Imager (HMI) show that “if the Sun were shrunk to a ball one meter in diameter, its equatorial diameter would be only 17 millionths of a meter larger than the diameter through its North-South pole,” according to PhysOrg. The shape is also remarkably constant over time. Even with its slow rotation, it should flatten into an oblate shape more than is observed; besides, it is a turbulent surface filled with magnetic disturbances and flares. “For years we’ve believed our fluctuating measurements were telling us that the sun varies, but these new results say something different,” the team leader of the observations said. “While just about everything else in the sun changes along with its 11-year sunspot cycle, the shape doesn’t.”
Another new moon theory: How long have the textbooks said that a glancing blow from a Mars-size object hit the earth and formed the moon? Time for another revision. Science Now entertained a new theory that it might have been a direct hit. The article, “Moon Formed From Head-On Collision,” came ready-made with new artwork.
Some 4.53 billion years ago, a Mars-sized impactor slammed into Earth, forming a young, molten moon. But was it a head-on collision or a glancing blow? New computer simulations argue for the former, indicating that the impactor scored a direct hit, crashing into Earth at a steeper angle and with a higher velocity than previously thought. The resulting smashup would have ejected far more Earth debris into space than other models have indicated, with much hotter temperatures. And that would mean the moon formed from more Earthlike material than previously thought. The origin of the impactor itself remains an open question….
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