In 1978, astronomer Andrew J. R. Prentice revived the Laplacian nebular model in his Modern Laplacian Theory by suggesting that the angular momentum problem could be resolved by drag created by dust grains in the original disc, which slowed down rotation in the centre. Prentice also suggested that the young Sun transferred some angular momentum to the protoplanetary disc and planetesimals through supersonic ejections understood to occur in T Tauri stars. However, his contention that such formation would occur in toruses or rings has been questioned, as any such rings would disperse before collapsing into planets.