Abell 2218 is the largest known galaxy cluster in the universe, containing over 1,000 galaxies.

Jayant Narlikar is an Indian astronomer and cosmologist who has made significant contributions to the study of the dynamics of galaxy clusters.

The characteristic temperature of a galaxy cluster is typically around 10^8 K.

M. N. Vahia is an Indian astronomer who has made significant contributions to the study of X-ray emission from galaxy clusters.

The primary source of energy in a galaxy cluster is the gravitational potential energy of the member galaxies.

T. Padmanabhan is an Indian astronomer and cosmologist who has made significant contributions to the study of the formation and evolution of galaxy clusters.

The typical mass of a galaxy cluster is around 10^14 Msun.

P. K. Iyengar is an Indian astronomer who has made significant contributions to the study of the dark matter content of galaxy clusters.

Dark matter dominates the mass of galaxy clusters.

A. K. Kembhavi is an Indian astronomer who has made significant contributions to the study of the Sunyaev-Zel'dovich effect in galaxy clusters.

The Sunyaev-Zel'dovich effect is the distortion of the cosmic microwave background radiation by galaxy clusters.

Govind Swarup is an Indian astronomer who has made significant contributions to the study of the radio emission from galaxy clusters.

Radio emission from galaxy clusters can be used to study the magnetic fields, detect active galactic nuclei, estimate the mass, and study the dynamics of the cluster.

Biman B. Nath is an Indian astronomer who has made significant contributions to the study of the gravitational lensing of light by galaxy clusters.

Gravitational lensing by galaxy clusters can be used to magnify distant galaxies, study the mass distribution, detect dark matter, and study the evolution of the cluster.