NASA’s Parker Solar Probe made history on Tuesday by flying into the sun’s outer atmosphere, called the corona, to help scientists learn more about earth’s closest star.
Launched in 2018 towards the centre of the solar system, the probe has already flown past the sun 21 times, getting ever closer, but its flight on Christmas Eve was a record-breaking one as it plunged into the outer atmosphere of the star, enduring brutal temperatures and extreme radiation.
It stopped communicating for several days during the hot flyby, and scientists are waiting for a signal from it, which is expected to arrive on December 28 (if it survives).
Dr. Nicola Fox, NASA’s chief science officer, told BBC News that the probe will help to better understand how the sun works.
At its maximum distance, the probe is 6.2 million kilometres from the sun’s surface.
“We are 93 million miles from the Sun, so if I place the Sun and Earth one metre apart, the Parker Solar Probe will be four centimetres from the sun – so that’s close,” Fox said.
The probe will have to withstand temperatures of 1,400°C and radiation that could disable on-board electronics. It is protected by an 11.5 cm thick carbon-composite shield. In fact, it will travel faster than any man-made object, reaching speeds of 692,017.92 kilometres per hour – the equivalent of flying from London to New York in less than 30 seconds.
The speed of Parker is due to the enormous gravitational pull it experiences as it falls towards the sun. Scientists hope that as the spacecraft passes through the sun’s outer atmosphere – its corona – it will solve a long-standing mystery.
“The corona is really very hot and we have no idea why,” Dr. Jennifer Millard, an astronomer at Fifth Star Labs in Wales, explained. She also added:
“The surface of the sun is about 6,000 °C, but the corona, this rarefied outer atmosphere that you can see during solar eclipses, reaches millions of degrees – and that’s further away from the sun. So how does this atmosphere get hotter?”
The mission should also help scientists better understand the solar wind – a constant stream of charged particles blasting out of the corona. When these particles interact with earth’s magnetic field, the sky lights up with dazzling auroras.
