Massive solar flare strikes Nasa spacecraft sent to study Sun

Probe cruised in at about 9.2 million km from the solar surface – closer than Mercury ever gets to the Sun

A massive solar flare has struck the closest spacecraft ever sent by humans to the Sun, revealing unprecedented insights into eruptions that have the potential to cause blackouts spanning continents.

Nasa’s Parker spacecraft, the fastest human-made object and the first-ever mission to ever “touch the Sun”, has now added another first to its belt by flying through a powerful solar explosion called a coronal mass ejection (CME).

The probe first detected the CME remotely before skirting along its flank, then passed into the structure and finally exited through the other side, scientists pointed out in a study published recently in The Astrophysical Journal.

It cruised in at about 9.2 million km (5.7 million miles) from the solar surface – closer than Mercury ever gets to the Sun.

Eruptions from the Sun expel billions of tons of charged particles at speeds ranging from 100-3,000km per second (60-1,900 miles per second).

When directed towards Earth, they can alter the planet’s magnetic field, generate spectacular auroras and also devastate satellite electronics and electrical grids on the ground, if strong enough.

“The potential damage of this class of event, large and very fast CMEs, can be colossal,” said Parker project scientist Nour Raouafi at the Johns Hopkins University.

“This is the closest to the Sun we’ve ever observed a CME. We’ve never seen an event of this magnitude at this distance,” Dr Raouafi said.

The research was published earlier this month, a full year after the spacecraft experienced the massive solar storm.

In the process, the spacecraft spent about two days observing the solar storm, revealing an unparalleled view into these stellar events.

As the probe passed behind the CME’s shockwave, its suite of instruments clocked particles accelerating up to 1,350km (840 miles) per second.

If such a flare had been directed towards Earth, Dr Raouafi suspects it may have been close in magnitude to the Carrington Event – an 1859 solar storm held as the most powerful on record to hit Earth.

Such an event today, if detected too late, could disable communications systems and lead to continent-wide blackouts, researchers said.

However, the Parker probe was unfazed thanks to its heat shield and radiators, while its thermal protection system ensured its temperatures never changed.

Scientists are currently working to piece together how the event unfolded by comparing measurements collected by the probe within the CME with those gathered outside it.

“You try simplified models to explain certain aspects of the event, but when you are this close to the Sun, none of these models can explain everything,” said study lead author Orlando Romeo from the University of California, Berkeley.

“We’re still not exactly sure what is happening there or how to connect it,” Dr Romeo said.

Researchers said the spacecraft is likely to observe more such massive CMEs as the Sun approaches solar maximum – a peak in its 11-year activity cycle that is expected in 2025.

The spacecraft’s next solar flyby is set to occur on 27 September.