Administration: Individual. The DAB-4 is a revision of one of the most popular individual achievement tests available. Its 8 subtests identify studentsâ strengths and weaknesses across important areas of school achievement. A supplemental manual shows how to probe student responses to obtain information about studentsâ thinking processes and problem-solving strategies.
In 1992, the first evidence of a planetary system other than our own was discovered, orbiting the pulsar PSR B1257+12. Three years later, 51 Pegasi b, the first extrasolar planet around a Sunlike star, was discovered.
Scientists have found nearly 2,000 alien planets since the first such world was confirmed orbiting a sunlike star in 1995. More than half of these discoveries were made by NASA's Kepler space telescope, which launched in 2009 on a mission to determine how common Earth-like planets are throughout the Milky Way galaxy.