NASA's Nuclear Spectroscopic Telescope Array has been orbiting our planet since its launch in 2012, mostly using its highly sensitive equipment to pick up the X-ray output of objects like black holes and supernovas, located thousands of light years from Earth. Sometimes, though, the NuSTAR space telescope is turned on a celestial object a lot closer to home -- our own sun -- and the results can be striking.
In this composite image released Wednesday by NASA, the data collected from NuSTAR has been combined with images from Japan's Hinode spacecraft and NASA's Solar Dynamics Observatory (SDO). NuSTAR captured high-energy X-rays, shown here in blue; Hinode captured low-energy X-rays, shown in green; and SDO grabbed images of extreme ultraviolet light, rendered here in yellow and red. NASA says all the images were taken around the same time on April 29.
"What's great about NuSTAR is that the telescope is so versatile that we can hunt black holes millions of light-years away and we can also learn something fundamental about the star in our own back yard," Brian Grefenstette of the California Institute of Technology said in a statement. Grefenstette is an astronomer on the NuSTAR team.
Because its instrumentation is extremely sensitive, the telescope can't be used to study larger solar flares. But it is quite good at picking up smaller eruptions known as microflares that produce one-millionth the energy of larger flares.
This means that NuSTAR could help astronomers get a better understanding of the sun -- especially as it begins to enter a quieter period in its 11-year cycle called a solar minimum. It's possible that the telescope could help observers pick up hypothetical nanoflares -- eruptions that would be one-billionth the energy of regular flares and that could be a reason why the sun's atmosphere is hotter than previously thought. There's also a "slim chance" the telescope could detect a dark-matter particle called the axion.
"Dark matter is a mysterious substance in our universe that is about five times more abundant than the regular matter that makes up everyday objects and anything that gives off light," says NASA. "NuSTAR might be able to address this and other mysteries of the sun."