Explaining why the universe can be transparent

Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.

Drilling Down into Mars

(PhysOrg.com) -- NASA's Phoenix lander revealed water ice mere inches beneath the martian surface, and chemical evidence from the landing site strongly hints that the region is habitable. But learning whether there is life ...

Melanin's 'trick' for maintaining radioprotection studied

Sunbathers have long known that melanin in their skin cells provides protection from the damage caused by visible and ultraviolet light. More recent studies have shown that melanin, which is produced by multitudes of the ...

Game-changing nanodiamond discovery for MRI

A Northwestern University study shows that coupling a magnetic resonance imaging (MRI) contrast agent to a nanodiamond results in dramatically enhanced signal intensity and thus vivid image contrast.

Disruption of giant molecular clouds by massive star clusters

(PhysOrg.com) -- New computer simulations show that the light from massive stars is, by itself, enough to blow apart the nebula where the stars are born. While this 'radiation pressure' was by and large overlooked in the ...

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Ionizing radiation

Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them. The occurrence of ionization depends on the energy of the impinging individual particles or waves, and not on their number. An intense flood of particles or waves will not cause ionization if these particles or waves do not carry enough energy to be ionizing. Roughly speaking, particles or photons with energies above a few electron volts (eV) are ionizing.

Examples of ionizing particles are energetic alpha particles, beta particles, and neutrons. The ability of electromagnetic waves (photons) to ionize an atom or molecule depends on their wavelength. Radiation on the short wavelength end of the electromagnetic spectrum - ultraviolet, x-rays, and gamma rays - is ionizing.

Ionizing radiation comes from radioactive materials, x-ray tubes, particle accelerators, and is present in the environment. It is invisible and undetectable by human senses, so instruments such as geiger counters are required to detect its presence. It has many practical uses in medicine, research, construction, and other areas, but presents a health hazard if used improperly. Exposure to radiation causes microscopic damage to living tissue, resulting in skin burns, radiation sickness and death at high doses and cancer, tumors and genetic damage at low doses.

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