There’s a comet that has broken apart even before appearing on Earth’s sky last year. But the thing is that it has given us a great gift. Its tail is still going through the Solar System, and there’s a spacecraft that’s orbiting the Sun, which was able to pass the tail. We now know exactly how the tail looks.
The Comet C/2019 Y4 was found back in December 2019, and it was supposed to get so close to Earth to be visible with the naked eye. But before that could happen, the comet disintegrated.
Last year, in April, the Hubble Space Telescope showed us a fragment of the comet – it was shattered. The spacecraft was not made for an encounter with the comet, and the instruments were not supposed to be used. But the scientists pushed the limits with it.
The team wanted to go more into it, even if there wasn’t anything to find out the comet. But when Solar Orbiter decided to meet with the tail of the comet, they did find something.
The leader of the team, Lorenzo Matteini, physicist, stated: “We have identified a magnetic field structure observed at the beginning of June 4th 2020, associated with a full magnetic field reversal, a local deceleration of the flow and large plasma density, and enhanced dust and energetic ions events.” They looked at this structure as a magnetic field going around an object that’s of high-density and of low-field – as it is, actually, expected. There are plenty of ion-scale fluctuations inside, with small-scale waves and structures that are generated by ion instabilities.
Comets usually come with two tails: a dust one – made by the dust that’s ejected as icy material sublimates. The radiation pressure from the Sun and the solar wind push the dust away, making it a tail; there’s also the ion tail – made when solar ultraviolet light ionizes molecules in the coma. This is also pushed away by solar winds.