<blockquote><font class="small">In reply to:</font><hr /><p>if the law of conservation of mass says that matter and mass dont change regardless how it is acting, then if the big bang expand so huge and imagine all the mass of the stars and dust and ice and comet and every galaxy in one small tiny spot so small that if u drop it u wouldnt relaly see it but you can get it back cos it would be so heavy that it make a biggg hole out of where it land...that is pretty weird, but i wonder if thats possible though.<p><hr /></p></p></blockquote><br />The infinitesimal speck of matter at the beginning of the Universe is generally referred to as the Monobloc. And yes, it was extremely massive, containing essentially all the normal matter, energy and dark matter present in the Universe today (last I heard, dark energy may have come from somewhere else). As a result, yes, it was extremely dense. Infinitely dense, in fact, right at the beginning of the Universe. And still extremely dense for several milliseconds after that, while the Universe was still relatively small.<br /><br />Perhaps fortunately for us, nothing quite like it exists now. However, there is a substance called neutronium (matter composed entirely of neutrons) which is extremely dense and does exist inside neutron stars. Now, under most conditions any small quantity of it would immediately explode, but if we have some hypothetical way of keeping it together, it becomes a very interesting toy. It has a density of approximately 400000000000 kilograms per cubic centimeter. In other words, if a billion cars have been built throughout history, and they average two tonnes each, then the same mass in neutronium would fit in the palm of your hand. Each cubic centimeter of neutronium also weighs 8 kilograms for ever dollar in Bill Gates' bank account. As a result of its enormous density, a piece of neutronium, when dropped, would fall just as fast as anything else you dropped- but when it hit something, it would go on falling at the sam <div class="Discussion_UserSignature"> <p>________________</p><p>Repent! Repent! The technological singularity is coming!</p> </div>