NASAのインスタグラム(nasagoddard) - 11月28日 06時28分

Comet ISON Approaching the Sun!

Comet ISON moves ever closer to the sun in this movie from the ESA/NASA Solar and Heliospheric Observatory, captured in the early hours of Nov. 27, 2013. A coronal mass ejection explodes off the sun – it is unlikely to damage ISON even if they cross paths.

As Comet ISON heads toward its closest approach to the sun — known as perihelion — on Nov. 28, 2013, scientists have been watching through many observatories to see if the comet has already broken up under the intense heat and gravitational forces of the sun. The comet is too far away to discern how many pieces it is in, so instead researchers carefully measure how bright it is, which can be used to infer its current state.
Has Comet ISON broken up? (#WillItBreakUp) It is still unclear.

At times observations have suggested ISON was getting dimmer and might already be in pieces. However, over Nov. 26-27, 2013, the comet once again brightened. In the early hours of Nov. 27, the comet appeared in the view of the European Space Agency/NASA mission the Solar and Heliospheric Observatory in the Large Angle and Spectrometric Coronagraph instrument.
If the comet has already broken up, it should disintegrate completely as it makes its slingshot around the sun. This would provide a great opportunity for scientists to see the insides of the comet, and better understand its composition — as such information holds clues about what material was present during the solar system's formation when this comet was born. However, it would likely mean no comet visible in the night sky in December. We'll only know for sure after the comet rounds the sun on Thanksgiving Day.

Credit: ESA/NASA/SOHO #nasagoddard #CometIson #WillItBreakUp #sun #earth #ISON

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