Despite being discovered 20 years ago, very little is known about brown dwarfs - notably why they fail to grow into stars. Scientists say part of the answer probably lies in the physics of how dense plasmas merge inside them.

Now researchers, led by the York Plasma Institute at the University of York and the UK's Science and Technology Facilities Council's (STFC) Central Laser Facility, have created "lumps" of plasma to recreate the conditions similar to those found deep inside brown dwarfs.

They were able to do this using one of the world's most powerful lasers, STFC's Vulcan Petawatt that is based at their Oxfordshire laser laboratory, to create the first test of resistivity and viscosity found in brown dwarfs.

Brown dwarfs bridge the gap between very low mass stars and planets and share characteristics with both.

Despite being numerous across the immensity of space, these little "starlets" are hard to spot because they are small and cool in temperature so tend to be faint and difficult to record.

But by measuring the x-rays emitted from these objects, the researchers were able to build up a profile of how dense plasmas form inside brown dwarfs.

The results, published in Nature Communications, pave the way towards furthering our understanding of these celestial objects.