The Future of Gravity-wave Research

Even as LIGO was being readied for operation, scientists were making plans to increase its sensitivity by as much as 10 times with more advanced equipment and measuring techniques. Those upgrades, which will be made only if LIGO proves itself successful, were to begin around 2005. Among the major planned improvements for the observatory—to be renamed LIGO II—were a more powerful laser, even better cushioning against vibrations, and the installation of pure sapphire mirrors to increase the instrument's sensitivity. While LIGO was designed to detect one black-hole collision as far away as 300 million light-years once a year, LIGO II was expected to be able to detect such events up to 6 billion light-years away, perhaps as often as 10 times a day.

Depending on the success of LIGO, gravity-wave astronomy may get an enormous boost from a proposed space-based instrument called the Laser Interferometer Space Antenna (LISA) around 2010. LISA, a $500-million joint project between the U.S. National Aeronautics and Space Administration and the European Space Agency, would be a laser interferometer composed of three satellites. The satellites would be positioned in a triangular configuration in orbit around the sun, about 50 million kilometers (30 million miles) behind Earth. The satellites would be about 5 million kilometers (3 million miles) from one another, making the instrument tens of thousands of times more sensitive than any Earth-based detector.

Scientists expected that by 2010 gravity waves would become yet another tool astronomers could use to learn more about the universe. Instruments like LIGO and its more powerful successors might open up a new window on the universe, helping to unravel some of its deepest mysteries.