Astrophysical fluid dynamics she pulls in her arms. These stars gradually slow down over the eons, but those bodies that are still spinning rapidly may emit radiation that from Earth appears to blink on and off as the star spins, like the beam of light from a turning lighthouse. This "pulsing" appearance gives some neutron stars the name pulsars. After spinning for several million years pulsars are drained of their energy and become normal neutron stars. Few of the known existing neutron stars are pulsars. Only about 1,000 pulsars are known to exist, though there may be hundreds of millions of old neutron
Beam dump also be issues. Considerable quantities of material may be put around the beam dump, especially "downstream" of the beam dump, to serve as radiation shielding. Also, the beam may be carefully not aimed at anything critical (such as people or particle detectors), and angled down into the earth before it hits the beam dump, so that soil serves as a radiation shield. The most challenging beam dump design to date is that of the Large Hadron Collider. Each of the two beam dumps, in case, for instance, of a dipole magnet quench, must be able to dissipate 362 MJ (approximately