Final answer:
When matter is heated to extreme temperatures greater than 10,000 degrees Celsius, it can explode, releasing X-ray and ultraviolet radiation. It can also produce shocks when it collides with interstellar gas, heating the gas to temperatures of millions or tens of millions of degrees.
Step-by-step explanation:
When matter is heated to extreme temperatures greater than 10,000 degrees Celsius, several things can happen depending on the specific circumstances. One possibility is that the matter can explode, releasing a flood of X-ray and ultraviolet radiation. This can occur when the matter associated with a flare is heated to temperatures as high as 10 million Kelvin. Another possibility is that the matter can produce shocks when it collides with interstellar gas, heating the gas to temperatures of millions or tens of millions of degrees.