| In the billions of years since, they have cooled to less than three degrees Kelvin above absolute zero, equivalent to microwave frequencies. |
| In fact, to quash all doubts, zero on the Kelvin scale is dubbed absolute zero. |
| But in recent years researchers have found a handful of complex metal-free materials that can become magnetic at temperatures near absolute zero. |
| A regular incandescent light bulb relies on the fact that all bodies with a temperature greater than absolute zero emit radiation. |
| After having cooled off for many billions of years, the temperature of this radiation is just a few degrees above absolute zero. |
| At absolute zero the internal energy of the system would be zero since temperature is proportional to internal energy. |
