A sedimentation rate is common blood test that is used to detect and monitor inflammation in the body. The sedimentation rate is also called the erythrocyte sedimentation rate because it is a measure of the red blood cells (erythrocytes) sedimenting in a tube over a given period of time. Sedimentation rate is often abbreviated as sed rate or ESR. Although this test measures a general state of inflammation, it is not specific to what causes the inflammation. It is elevated in inflammatory diseases, including arthritis as well as in autoimmune diseases such as lupus.
Earth spins because of the way it was formed. Our Solar System formed about 4.6 billion years ago when a huge cloud of gas and dust started to collapse under its own gravity. As the cloud collapsed, it started to spin. Some of the material within this cloud gathered into swirling eddies and eventually formed into planets.
Most people know that the Earth revolves around the Sun in one year (actually. 365.24 days and we add one day to the calendar every four years, for a âleap. yearâ). Most also know that it takes 24 hours (actually 23 hours and 56 minutes) for the Earth to make a full rotation on its axis. Fewer people know that the Earthâs orbit is elliptical, or oval shaped, and that the Earth is sometimes slightly closer to the Sun than at other times, but this is not what causes the seasons, in fact we are closest to the Sun in January! Seasons are caused by the fact that the âEarth is tiltedâ (see Figure 1). What we mean by that is that the Earthâs axial tilt is at an angle of 23.5 degrees relative to the plane of the Ecliptic, its plane of orbit around the Sun. And the imaginary line, on which the Earth rotates, its axis, is tilted close to Polaris, the North Star.