The accretion of matter onto moving cosmic string is discussed carefully.It is found that the'accreting matter in the wake has not only transverse velocity but also vertical velocity.The vertical velocity of the a...The accretion of matter onto moving cosmic string is discussed carefully.It is found that the'accreting matter in the wake has not only transverse velocity but also vertical velocity.The vertical velocity of the accreting matter depends on that of moving string.展开更多
Hartle and Hawking (hereafter HH) have given a model of universe in which the universe originates from nothing, here nothing means no classical space-time. They suggest that the initial boundary condition of space-tim...Hartle and Hawking (hereafter HH) have given a model of universe in which the universe originates from nothing, here nothing means no classical space-time. They suggest that the initial boundary condition of space-time is no boundary, so the universe is self-contained and has no problem of out-boundaryt. Go a step further, it will be quite interesting to consider a universe where there is not only no classical space-time but also no gravity initially.展开更多
文摘The accretion of matter onto moving cosmic string is discussed carefully.It is found that the'accreting matter in the wake has not only transverse velocity but also vertical velocity.The vertical velocity of the accreting matter depends on that of moving string.
文摘Hartle and Hawking (hereafter HH) have given a model of universe in which the universe originates from nothing, here nothing means no classical space-time. They suggest that the initial boundary condition of space-time is no boundary, so the universe is self-contained and has no problem of out-boundaryt. Go a step further, it will be quite interesting to consider a universe where there is not only no classical space-time but also no gravity initially.