<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>In fact, as far as I know, there isn´t! Stars can gorw large, very large, but it depends on 0many factors as density and volume.Large stars as LY Canis Major (if it puts in our sun´s place it will reach saturn orbit) are incredibly huge, but it´s not that massive as other stars. Size and mass are not directly related when we talk about stars.Massive stars, real massive stars will last only a few million years, with a high density and not so bigger than our sun.It´s a confuse stuff, I know! I´m not expert and I probably talking a lot of bullshit, but, as I said, as far as I know theres no real limit for a star grow! <br />Posted by Ricardo_Savino</DIV></p><p>First, richard, whatever means you use to reply is very hard to read. It comes through on my IE7 as very long sentences that I have to scroll to read. Your original posts don't do that, but your replies do. Just a comment.</p><p>To get to the question at hand, star size is limited by the mass in the gas/dust cloud, and then a delicate interplay between gravity drawing material in, and heating that occurs from the gravitational collapse. Exactly what gas or dust is included makes a diffence as well, since it affects the dissapation of the heat.</p><p>Heat causes (actually is) faster molecular motion which expands the cloud, while gravity contracts the cloud. It's rather like a functioning fusioning star. It's a balance between gravity and heat, only far more delicate from what we understand now.</p><p>It is suspected (though an area of active research) that the earliest stars, consisting of only hydrogen and helium could grow much larger; once metals (anything heavier than helium) are mixed in the heating limits how much mass can be absorbed before it is blown away. Since "in the beginning" there was only H, He, and a bit of Li, that describes the first stars. After those massive (short lived) stars exploded, the pollution that allows planets and humans was distributed through space and used in the next round of star making. Smaller stars, and other stuff, like us..<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /></p><p>And of course, once fusion starts, whatever gas/dust is in the cloud stops falling in, and hence is available to form planets, asteroids, and the other rubble of stellar systems</p><p>That's my inderstanding anyway; I'm not an expert in stellar evolution, but I am a reading addict....<br /></p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>