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).
1 Radiation burns are caused by the sun, tanning booths, sunlamps, X-rays, or radiation therapy for cancer treatment. 2  Friction burns are caused by contact with any hard surface such as roads (road rash ), carpets, or gym floor surfaces. 3  They are usually both a scrape (abrasion) and a heat burn.