albert_eimstymied - On your original question, the answers seem to be concerning the temperature of the CMB, or cosmic microwave background radiation.<br /><br />The temperature of the universe is not uniform. As one dramatic example, the temperature of the IGM (= Intergalactic medium) is extremely hot - way hotter than 25C at this time.<br /><br />On terrestrial planets - do you mean earthlike planets?<br /><br />Before planets, stars would have to synthesize the elements that make up planets. <br /><br />There is current research on the earliest generation of stars, well before our sun was formed. <br /><br />I forget the details, but some were much shorter in lifespan than our sun - so elements were synthesized long ago.<br /><br />As for origin of life, I assume you mean life as we know it. For logical, scientific reasons I consider it logical to believe life was created rather than evolved by chance.<br /><br />Either way, though, you need an environment that would sustain life as we know it.<br /><br />Planets can, of course, escape gravitational capture by a star - so, yes, such planets could theoretically exist.<br /><br />I am not aware, however, of any observational evidence that such star-less planets exist.<br /><br />Such planets would be very cold unless, like Io if I remember correctly, tidal interactions with a larger planet cause internal heat to buildup - and then a thick insulating atmosphere holds said heat in.<br /><br />In other words, a planet that while it is star-less, nevertheless orbits a large planet.<br /><br />Hope that helps!<br /><br />