resist destructive testing beyond the theoretical limits of material strength. However, they are not completely indestructible: The Great Wall Monolith (perhaps the same as TMA-2) was knocked on its side and suffered from damage caused by a giant meteorite of solid diamond that collided with Europa in 2061: Odyssey Three. In the final book, 3001: The Final Odyssey, all three Monoliths known to humankind are deactivated by being infected with a powerful computer virus. While it is unclear what the composition of the Monoliths is, they clearly have mass, which is about the only observation that can be made. In the novel 2010, the crewmen of the spaceship Alexei Leonov measure the mass of TMA-2 and find that it has a density slightly higher than that of air. The masses of TMA-0 and TMA-1 are never revealed by Clarke. In 2001, TMA-2 opens up a stargate that takes Dave Bowman on a trip across the universe at faster-than-light speeds, and with as much acceleration as the creators of the stargate wish. In 2010 and again in 3001, TMA-2 teleports itself. TMA-2 replicates itself by a form of symmetrical binary fission and exponential growth to create thousands or millions of identical Monoliths in just a matter of days. In 2010, the many units act to increase the density of Jupiter until stellar ignition is carried out, converting the planet into a miniature star. In 3001, millions of copies of TMA-2 assemble themselves into two megastructure disks that attempt to block the Sun from Earth and Lucifer from its colonies in the Jovian system. The Monoliths are clearly described in the novels as controlled by an internal computer, like Von Neumann machines. In 2061, the consciousness of Dave Bowman, HAL-9000, and Dr. Floyd become incorporated as computer programs in TMA-2 as their new home. TMA-2 then observes the development of the Europans and guards them from any interplanetary (i.e. human) interference. Both TMA-1 and TMA-2 produce occasional, powerful, directional radio transmissions. TMA-2 sends a radio transmission towards a star system about 450 light years away in the 22nd century. However, only TMA-1 ever exhibited any strong magnetic fields. Actions The TMA-2 Monolith had judged that it would be desirable to nurture the primitive Europans by preventing the eventual freezing of their moon, and to keep humanity separated from them. TMA-2 thus converted Jupiter into a new star (dubbed "Lucifer", meaning "light-bringer") to