As comets move close to the Sun, they develop tails of dust and ionized gas. Comets have two main tails, a dust tail and a plasma tail. The dust tail appears whitish-yellow because it is made up of tiny particles â about the size of particles of smoke â that reflect sunlight. Dust tails are typically between 1 and 10 million kilometers (about 600,000 to 6 million miles) long.
Hyperhidrosis, or excessive sweating, is a common disorder which produces a lot of unhappiness. An estimated 2-3% of Americans suffer from excessive sweating of the underarms (axillary hyperhidrosis) or of the palms and soles of the feet (palmoplantar hyperhidrosis). Underarm problems tend to start in late adolescence, while palm and sole sweating often begins earlier, around the age 13 (on the average). Untreated, these problems may continue throughout life. Sweating is embarrassing, it stains clothes, ruins romance, and complicates business and social interactions.
Sweaty Feet â Causes, Prevention & Treatment. Sweating is our bodyâs natural way of cooling itself down. Sweaty feet, or hyperhidrosis, is a common condition that causes excessive sweating on the soles of the feet. The condition also affects the palms of the hands and the underarms, but in this article we will focus only on the feet. Plantar hyperhidrosis is localized to the plantar side of the foot (the bottom).