EINSTEIN, Albert (1879-1955). Näherungsweise Integration der Feldgleichungen der Gravitation. Offprint from: Sitzungsberichte der Königlich preussischen Akademie der Wissenschaften, XXXII. Berlin, 1916.

Author's presentation offprint of Einstein's visionary proposal of the existence of gravitational waves, from the library of his son Hans Albert Einstein. The present work was Einstein's first paper on gravitational waves, predicting the existence of ripples in space-time caused by massive accelerating objects like colliding black holes, supernovae, and even the Big Bang. Proof of their existence was not discovered until 1974, when the Arecibo Radio Observatory allowed astronomers to measure a binary pulsar over the course of eight years, confirming Einstein's proposal. In 2015, LIGO—the Laser Interferometer Gravitational-wave Observatory—was able to physically sense undulations in space time caused by colliding black holes for the first time. This association copy belonged to Einstein's eldest son, Hans Albert, who was a professor of Hydraulic Engineering at Berkeley from 1947 until his death (as professor emeritus) in 1973. BRL 88.

Octavo (253 x 179mm). Pp. 688-696. Original printed wrappers with "Überreicht vom Verfasser" at top. Provenance: Hans Albert Einstein, 1904-1973 (his stamp with Berkeley address on cover).