Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time. On April 16, 2017 there were 11 potentially hazardous asteroids.
Radiation therapy is often delivered from a machine outside the body. One of the most common side effects is a skin condition called radiation dermatitis, which can range from a mild, red rash (erythema) and itchy, peeling or flaking skin (dry desquamation) to a more severe reaction with blisters and wet, peeling skin (moist desquamation).
The most common short-term side effects of radiation therapy for prostate cancer include fatigue, slight reddening of the skin in the treatment area, temporary lowering of blood counts, and urinary and bowel side effects. Brachytherapy and radium 223 dichloride may have some additional or different side effects.