Extract from ABC News
The sun is a hot place in our solar system with a core temperature of 15 million degrees Celsius.
Key points:
- Scientists are trying to figure out why the Sun's outer atmosphere is hotter than its surface
- Colorado astrophysicists have travelled thousands of kilometres to Exmouth for 58 seconds of data collection
- A star's corona can reach temperatures higher than 1 million degrees Celsius
Its surface is relatively cool at about 6,000 degrees, but then things get interesting again with its corona, the outer atmosphere, rising again to more than 1 million degrees.
A group of American scientists have travelled thousands of kilometres from Colorado to Perth and then 13 hours in a car to Exmouth to try solve the solar mystery of why the sun's corona is so toasty.
And the pressure will be on as they only have 58 seconds to collect data during the total solar eclipse taking place in the north-west town on Thursday.
University of Colorado adjunct professor Kevin Reardon, who is also a scientist at the US National Solar Observatory, said scientists had been trying to figure out why the corona got so hot for a long time.
"The corona is the layer that extends out above that out into space and the curious thing is, it's not very dense, there's not a lot of material there," he said.
"But it gets very hot, much hotter than the photosphere, up to a million degrees Kelvin [and Celsius] or more. And the question is how that happens.
"We've been trying to puzzle that out now for a long time. It's still a mystery."
Looking at where the heating is
Brought along on the long haul eclipse road trip is a telescope and a spectrograph, a tool that splits light into wavelengths to be recorded.
Dr Reardon said by carefully analysing the spectrum from the corona, they would be able to figure out where the heating was happening.
"We'll be able to figure out exactly what the temperature is in different parts of the corona and at different heights," he said.
It won't just be the scientists on the ground in Exmouth, however, with data collection happening at the same time from NASA's Parker Solar Probe, launched in 2018, which will be able to make simultaneous observations for comparison.
For University of Colorado PhD student Sarah Bruce, who gets to crunch the data collected on the trip, the total solar eclipse on Thursday will be her first.
"I feel really lucky to be able to see a total eclipse at all," she said.
"Because I know it's something that plenty of people will never be able to see.
"Just from a personal perspective, I'm just really excited to see it.
"But I'm also really looking forward to seeing what the process is like of setting up all our instruments and using them."
Dr Reardon is also looking forward to seeing the familiar faces of other scientists from around the world who chase eclipses for various studies.
"There's people who study the effects on the Earth's atmosphere from eclipses ... there's really a lot of variety of science that can be done and so people like to take advantage of it as we are," he said.
Confusing for animals
The eclipse will attract plenty of Australian scientists too, including University of Western Australia astrophysicist Robin Cook.
For Dr Cook, it will also be his first total solar eclipse.
He said while humans were quite impressed by the spectacle, the animals within the path of totality, where it becomes dark for 58 seconds, would be confused.
"You've got complete darkness happening over a matter of a few minutes, and the temperatures will drop quite rapidly, wind direction can change," Dr Cook said.
"And so all these are cues to the fauna around that they should be returning to their night-time abodes.
"So it's a really bizarre time to experience not just the astronomical sense of it, but what's happening on the Earth as well, as things are dramatically changing over only the space of a few minutes."
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