NASA's Parker probe reached its closest point to the Sun on Tuesday, a promising new record for the data it will have collected on our star. This information will allow us to better understand the phenomena linked to solar winds.
While traveling at more than 690,000 km/h, the probe named in honor of the astrophysicist behind the discovery of solar winds, Eugene Parker, came within 6.2 million kilometers of the Sun on Tuesday.
This is the shortest distance from the Sun reached by a probe to study the star, whose surface temperature rises to 5800 degrees Celsius.
Launched in 2018, the probe accelerated into the orbit of Venus before embarking on a journey at full speed around the Sun, gradually getting closer with each revolution, until reaching its closest point, at 6.2 million kilometers.
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The solar corona, which the Parker probe analyzes, can be seen during a solar eclipse. It is a bright, white, diffuse “halo”.
Photo: AP / Mark Schiefelbein
This distance may seem very large to Earthlings, but it is in fact very short on an astronomical scale.
Six million kilometers is very little in terms of orbit
underlines Alexandre Lemerle, physics teacher at the Collège de Bois-de-Boulogne and researcher specializing in solar astrophysics at the University of Montreal, invited to comment on this feat on the show's microphone. All one morning.
To give a little idea, the Earth is [située] 150 million kilometers away [du Soleil]; Mercury, around fifty million. The Sun has a radius of 700,000 kilometers. We are really very, very close to the star.
At this distance, the probe penetrates the Sun's atmosphere, and more precisely the solar corona.
It is a gaseous layer of very low density which extends over nearly ten million kilometers around the star and whose temperature is far higher than that of the surface: it can reach millions of degrees. Celsius.
This temperature difference between the surface and the corona remains a mystery to scientists. The data transmitted by the Parker probe, which are expected on December 27, should allow us to better understand this phenomenon.
It is the magnetic fields in the solar corona that must radiate their energy in some way, but it is not clear exactly how. This is important, because this solar corona is where the solar wind accelerates.
explains Alexandre Lemerle.
These winds travel to Earth and distort the Earth's magnetic field.
The pretty part of this is the Northern Lights, but it also affects the satellites orbiting the Earth.
Sometimes, during solar storms, the winds are of such intensity that they cause strong variations in the Earth's magnetic field, which can cause power outages like in 1989, illustrates the researcher.
A magnetic storm caused by a solar flare plunged Hydro-Québec customers into darkness for nine hours.
Last summer, several geomagnetic phenomena were also observed, but Hydro-Québec confirmed shortly after that none had caused an outage.
