Solar probe snaps closest-ever pictures of the Sun, revealing 'campfires' on the surface.

Extract from ABC News

Posted 1hour ago, updated 10minutes ago

Scientists say the images of the Sun were "much better" than they had expected.(AP: ESA/NASA)

A solar probe built by the European Space Agency (ESA) and NASA has delivered the closest photos ever taken of the Sun's surface, revealing a landscape rife with thousands of tiny solar flares that scientists have dubbed "campfires", offering clues about the extreme heat of the outermost part of its atmosphere.

Key points:

• Researchers had to come up with new vocabulary for tiny flare-ups on the Sun, calling them "campfires"
• The primary mission of the Solar Orbiter spacecraft is to examine the Sun's poles
• Coronavirus has forced scientists working on the project to work from home for months

The spacecraft, launched from the US state of Florida in February, snapped the images in late May using the probe's Extreme Ultraviolet Imager as it orbited nearly 77 million kilometres from the Sun's surface, or roughly halfway between the Sun and Earth.

"These are only the first images and we can already see interesting new phenomena," said Daniel Muller, ESA's Solar Orbiter Project Scientist.

"We didn't really expect such great results right from the start.

"We can also see how our 10 scientific instruments complement each other, providing a holistic picture of the Sun and the surrounding environment," he said.

The "campfires" are believed to be tiny explosions, called nanoflares, and could explain why the Sun's outer shield, the corona, is 300 times hotter than the star's surface.

The team had to create a new vocabulary to name the tiny flare-ups, Mr Muller said, describing them as quite possibly "the tiny cousins of the solar flares that we already know."

Images at this wavelength reveal the upper atmosphere of the Sun, the corona, with a temperature of around 1 million degrees.(Supplied: ESA & NASA)

Scientists are awaiting more data from the spacecraft's other instruments to know for sure.

"We've never been closer to the sun with a camera, and this is just the beginning of the long epic journey of Solar Orbiter," Mr Muller said.

Scientists typically have relied upon Earth-based telescopes for closeups of the sun's surface.

But Earth's atmosphere limits the amount of visible light needed to glean views as intimate as those obtained by the Solar Orbiter.

The Royal Observatory of Belgium's David Berghmans, principal scientist of the instrument that captured the images, said he was blown away.

He said his first response was: "This is not possible. It cannot be that good.

"It was really much better than we expected, but what we dared to hope for.

"The Sun might look quiet at the first glance, but when we look in detail, we can see those miniature flares everywhere."

The spacecraft also carries plasma-sampling instruments to offer researchers further data.

"That combination really allows us to make links and connections to what's happening on the Sun and what's happening at the spacecraft," said Holly Gilbert, Solar Orbiter project scientist at NASA.

Solar Orbiter's primary mission of examining the Sun's polar regions will help researchers understand the origins of the solar wind, charged particles that blast through our solar system and affect satellites and electronics on Earth.

The $US1.5 billion ($2.1 billion) spacecraft will tilt its orbit as the mission goes on, providing unprecedented views of the Sun's poles.

The COVID-19 pandemic has forced Solar Orbiter's scientists to work from home for months. Only a few engineers are allowed at any one time inside the control centre in Darmstadt, Germany.

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