Osteoarthritis is by far the most common form of arthritis, affecting about 16 million Americans, while rheumatoid arthritis, which affects about 2.1 million Americans, is the most crippling form of the disease.
Most Abundant Metal in the Earthâs Crust. Aluminium â Itâs the most abundant metal in the Earthâs crust, yet it entirely escaped our notice until 1825. You might say it was hidden in plain sight. Aluminium is a highly reactive metal, meaning it readily undergoes chemical reactions with other elements and compounds to form different substances.
Oxygen is the most abundant element in rocks in Earth's crust, composing roughly 47 percent of the weight of all rock. The second most abundant element is silicon at 27 percent, followed by aluminum at 8 percent, iron at 5 percent, calcium at 4 percent, and sodium, potassium, and magnesium at about 2 percent each.eologists think the temperature of Earth's outer core is about 6,700 to 7,800 degrees F (3,700 to 4,300 degrees C), and the inner core may reach 12,600 degrees F (7,000 degrees C), hotter than the surface of the sun. Only the enormous pressures found at the super-hot inner core keep it solid.