11.   In the meantime, the very existence of such rocks has scientists gleefully contemplating the possibilities.

12.   It has scientists capable of designing miniature atomic clocks to improve the accuracy of the instruments it sells to the aerospace industry.

13.   Last week, after decades of work in rodents, McClintock proved it in a study in Nature that has scientists buzzing.

14.   Other options were dropping a line from a hovering helicopter and snaring the robot, or having a scientist enter the crater to attach the line.

15.   Phantom limbs have puzzled scientists for years.

16.   This fleeting nature of gamma ray bursts has frustrated scientists for three decades.

17.   This latest age crisis has scientists conceding that the expansion of the universe may not be so simple and pondering what basic physical property they may have overlooked.

18.   A new theory that sunburns lower immune function has scientists considering a lymphoma link.

19.   But new genetic tests adopted by blood banks last year have many scientists expecting to virtually eliminate even those rare cases.

20.   Its precise cause has puzzled scientists for decades.