Plasa eruptions rushing into each other, a solar wind visible in its smallest detail: the closest images ever made of the sun are a gold mine to deepen our understanding of space weather and thus better protect the earth from solar threats.
Imagine this feat: if the distance between the earth and the sun was equivalent to one meter, the Parker probe would only be about four centimeters from our star to draw its portrait! In reality, it is 6.1 million kilometers [lire encadré].
This is the first time that an object made by our species has been found as close to a star. In comparison, the solar orbit of ESA remained in the orbit of Mercury 42 million kilometers from the sun.
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Other space probes had already studied the sun before, but at a much higher distance.
The solar crown and its ejections
“We have been waiting for this moment since the late 1950s,” said Nour Rawafi, scientific manager of the mission of this NASA machine. The images unveiled by the American agency were taken by Parker during the passage as close as possible to the sun on December 24, 2024.
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The unique camera of the vessel, the Wide-Field Imager for Parker Solar Probe (Wispr), captured images While the vessel explored the external layer of the atmosphere of the sun, called a crown.
Mounted in a short video of a few seconds, these new images reveal for the first time in high resolution of coronal mass ejections (CME), immense wreaths of ionized particles which play a role in the appearance of spatial weather phenomena.
These eruptions are notably at the origin of the spectacular northern lights visible in a large part of the world last May.
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“We have several stacons stacked on top of each other, that’s what makes them if unique,” said Nour Rawafi. “It’s really incredible to see this dynamic at work.”
When CMES collide, their trajectory may change, which makes it more difficult to forecast their final destination. Their fusion can also accelerate the loaded particles and mix magnetic fields, which makes the effects of CMES potentially more dangerous for astronauts and satellites in space, as well as for ground technology.
What impact on our land?
The other striking detail is the solar wind, visible on images as a flow from the left. It follows a structure called Heliospheric current tablecloth – an invisible border where the magnetic field of the sun rocks from north to south. A crucial limit to study, because it plays an essential role in the spread of solar eruptions and in their potential impact on earth. Spatial weather can indeed have heavy consequences: it can overload electrical networks and disrupt communications.
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>> Images taken by WISPR between September 25 and October 10, 2024::
While thousands of additional satellites must enter orbit in the coming years, their follow -up and the prevention of collisions are more and more complex, especially during solar disturbances, which can slightly shift their trajectory.
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The sun in the downward phase
Nour Rawafi is particularly enthusiastic for the future, while the sun is now heading for the minimum of its activity cycle, expected within five to six years.
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Some of the most extreme sunscreens took place during this descending phase, such as the famous “Halloween storms” of 2003, which had forced astronauts from the international space station to take additional precautions against radiation.
“Capture one of these gigantic eruptions … It would be a dream,” says the scientist.
Parker still has much more fuel than initially expected and could continue to operate for several decades, until its solar panels deteriorate to the point of no longer providing enough energy to maintain the orientation of the probe.
When its mission will finally end, the probe will slowly disintegrate until it becomes, according to Nour Rawafi, “part of the solar wind itself”. In the meantime, the next parker passage closest to the sun will take place on September 15.
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Stéphanie Jaquet and AFP