From wiki: "With a temperature of -272 °C, it is only 1 degree kelvin warmer than absolute zero (the lowest limit for all temperatures)."<br /><br />How can we measure the temperature of a nebula 5000LY away? Also, how can it reach such a cold state? I hope this is not too much to ask <img src="/images/icons/smile.gif" /><br /><br />Edit: The gas is moving outwards at a speed of about 164 km/s and expanding rapidly as it moves out into space. This expansion is the cause of the nebula's very low temperature<br /><br />This kind of answers my second question.<br /><br />Thanks.