There are four important warning signs that should prompt you to talk to a health care provider. 1  Pain. Pain from arthritis can be constant or it may come and go. 2  Swelling. Some types of arthritis cause the skin over the affected joint to become red and swollen, feeling warm to the touch. 3  Stiffness.
There's a whole lot of water on Earth! Something like 326,000,000,000,000,000,000 gallons (326 million trillion gallons) of the stuff (roughly 1,260,000,000,000,000,000,000 liters) can be found on our planet. This water is in a constant cycle -- it evaporates from the ocean, travels through the air, rains down on the land and then flows back to the ocean.
EARTH'S OCEANS Oceans cover about 70% of the Earth's surface. The oceans contain roughly 97% of the Earth's water supply. The oceans of Earth are unique in our Solar System. No other planet in our Solar System has liquid water (although recent finds on Mars indicate that Mars may have had some liquid water in the recent past).