以表彰他們對磁性旋轉不穩定性的發現和硏究。他們的工作說明了磁性旋轉不穩定性引發湍流，並足以解釋天體物理學裏吸積盤的角動量輸運機制。
2013年度邵逸夫天文學獎頒予史蒂芬．拜爾巴斯 (Steven A Balbus) 及約翰．霍利 (John F Hawley)，以表彰他們對磁性旋轉不穩定性的發現和硏究。他們的工作說明了磁性旋轉不穩定性引發湍流，並足以解釋天體物理學裏吸積盤的角動量輸運機制。拜爾巴斯為英國牛津大學 Savilian 天文學講座教授；霍利為美國維吉尼亞大學理學院副院長、VITA 講座教授兼天文學系主任。
吸積盤為天體物理學常見現象，在星體形成、雙星體系的質量轉移、及星雲中心的超大質量黑洞的成長等過程，均有重要影響。由吸積盤提供能量的天文學光源，以同等質量比較，其亮度可以超越一般倚賴核聚變獲取能量的星體。
The attractive force of gravity is responsible for the formation of bound structures over a wide range of scales, from planets to clusters of galaxies. Unbalanced, gravity would cause matter to collapse into black holes. Fortunately, the concentration of mass by gravity is impeded, at least temporarily, by the requirement that the contracting material rid itself of excess energy and angular momentum. Bulk kinetic energy can be converted into heat and radiated away but angular momentum is less readily disposed of. Consequently, contracting material often assumes the form of a differentially rotating disk. Familiar examples include Saturn’s rings and spiral galaxies. Nascent stars grow by accreting mass from disks that live several million years. The coplanar orbits of the solar system planets and multi-planet systems around other stars are vestiges of these disks.
More exotic accretion disks are found around compact objects such as white dwarfs, neutron stars and black holes. These systems shine by radiating gravitational potential energy released as mass spirals inward. For fluid to spiral in, its angular momentum must be transported out, but how this happens was for long a mystery. For decades, it was speculated that accretion disks were unstable and that the accretion torque arises from turbulent stresses. However, analytic analyses and numerical simulations consistently failed to identify any appropriate instability. In 1991 Balbus & Hawley announced an elegant solution to this longstanding problem. They demonstrated that even a weak seed magnetic field is sufficient to unleash a powerful instability, the magnetorotational instability (MRI), that both creates and sustains turbulence while also amplifying the magnetic field.
