It seems that even our Sun is helping spread the festive joy, bearing resemblance to a flaming Christmas pudding in this stunning new image from NASA.
This new view of our Sun was snapped by NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, which is a highly sensitive, space-based X-ray telescope launched into orbit back in 2012. And it’s not a bad picture for an amateur- this is the first time that the instrument has set its eyes on our Sun, and it’s produced the most sensitive solar portrait taken so far in high-energy X-rays.
The striking image is a composite, combining recently gathered NuSTAR data in green and blue, which reveals high-energy X-ray emissions, and data from NASA’s Solar Dynamics Observatory in red, which represents UV light.
NASA/JPL-Caltech/GSFC. Image shows NuSTAR data (blue/green) over SDO data (red), rotated so North is up.
NuSTAR was not actually built to be a solar photographer, but instead was designed to detect exotic objects deep in space such as black holes, supernovae and pulsars, which are a type of neutron star. But scientists began toying with the idea of using it to peek at our Sun during its construction phase, although not everyone was convinced this was a good use for the powerful instrument.
“At first I thought the whole idea was crazy,” NuSTAR’s principal investigator Fiona Harrison said in a news-release. “Why would we have the most sensitive high energy X-ray telescope ever built, designed to peer deep into the universe, look at something in our own back yard?”
But when it was pointed out that NuSTAR’s sensitivity has the potential to capture a hypothetical type of extremely faint X-ray activity, Harrison began to warm to the idea. These weak flashes, or nanoflares, are smaller and so far invisible versions of the Sun’s explosive solar flares. Although scientists have not yet gathered proof of their existence, it is believed that these miniature eruptions could explain the long standing mystery of why the Sun’s outer atmosphere, or corona, is so much hotter than its surface.
On average, the corona boasts temperatures of 1 million degrees Celcius (1.8 mnoF), whereas the surface averages a comparatively cooler 6000oC (10800oF). One hypothesis is that nanoflares, alongside their full-sized counterparts, could be responsible for this intense heat. And astronomers may be able to back up this idea if they can catch nanoflares in action.
“NuSTAR will be exquisitely sensitive to the faintest X-ray activity happening in the solar atmosphere,” says NuSTAR team member David Smith, “and that includes possible nanoflares.”
But what’s even more exciting is that NuSTAR might be able to spot a hypothetical, dark matter candidate particle called an axion. Dark matter is the invisible, elusive stuff that is thought to make up most of the universe, although scientists have no direct evidence for it, nor do they know what it’s comprised of. But if axions do indeed exist, they should appear as spots of X-rays in the Sun’s core.