Extragalactic cosmic ray Extragalactic cosmic ray Extragalactic cosmic rays are very-high-energy particles that flow into the Solar System from beyond the Milky Way galaxy. The energies these particles possess are in excess of 10 eV. Unlike solar or galactic cosmic rays, little is known about the origins of extragalactic cosmic rays. This is largely due to a lack of statistics: only about 1 extragalactic cosmic ray particle per square meter per year reaches the Earth's surface (see figure). There are many ideas about which processes may be responsible for cosmic rays with such high energies. In the 'bottom-up' approach, cosmic rays gain more
To Sail Beyond the Sunset To Sail Beyond the Sunset To Sail Beyond the Sunset is a science fiction novel by American writer Robert A. Heinlein, published in 1987. It was the last novel published before his death in 1988. The title is taken from the poem "Ulysses", by Alfred Lord Tennyson. The stanza of which it is a part, quoted by a character in the novel, is as follows: <poem> ... my purpose holds To sail beyond the sunset, and the baths Of all the western stars, until I die. </poem> It is the final part of the "Lazarus Long" cycle of stories, involving