Humans, like all known things in the universe, are in constant motion; The smaller scales of these motions are too small to be detected conventionally with human
senses.
Universe Spacetime (the fabric of the universe) is
expanding, meaning everything in the
universe is stretching, like a
rubber band. This motion is the most obscure, not involving physical movement but a fundamental change in the universe's nature. The primary source of verification of this expansion was provided by
Edwin Hubble who demonstrated that all galaxies and distant astronomical objects were moving away from Earth, known as
Hubble's law, predicted by a universal expansion.
Galaxy The
Milky Way Galaxy is moving through
space and many astronomers believe the velocity of this motion to be approximately relative to the observed locations of other nearby galaxies. Another reference frame is provided by the
Cosmic microwave background. This frame of reference indicates that the Milky Way is moving at around .
Sun and Solar System The Milky Way is
rotating around its
dense Galactic Center, thus the
Sun is moving in a circle within the
galaxy's
gravity. Away from the central bulge, or outer rim, the typical stellar
velocity is between . All planets and their moons move with the Sun. Thus, the
Solar System is in motion.
Earth The Earth is
rotating or spinning around its
axis. This is evidenced by
day and
night, at the equator the earth has an eastward velocity of . The Earth is also
orbiting around the
Sun in an
orbital revolution. A complete orbit around the Sun takes one
year, or about 365 days; it averages a speed of about .
Continents The Theory of
Plate tectonics tells us that the
continents are drifting on
convection currents within the
mantle, causing them to move across the surface of the
planet at the slow speed of approximately per year. However, the velocities of plates range widely. The fastest-moving plates are the oceanic plates, with the
Cocos Plate advancing at a rate of per year and the
Pacific Plate moving per year. At the other extreme, the slowest-moving plate is the
Eurasian Plate, progressing at a typical rate of about per year.
Internal body The human
heart is regularly
contracting to move
blood throughout the
body. Through larger veins and arteries in the body, blood has been found to travel at approximately 0.33 m/s, though considerable variation exists and peak flows in the
venae cavae have been found between . Additionally, the
smooth muscles of hollow internal
organs are moving. The most familiar would be the occurrence of
peristalsis, which is where digested
food is forced throughout the
digestive tract. Though different foods travel through the body at different rates, an average speed through the human
small intestine is . The human
lymphatic system is also constantly causing movements of excess
fluids,
lipids, and immune system related products around the body. The lymph fluid has been found to move through a lymph capillary of the
skin at approximately 0.0000097 m/s.
Cells The
cells of the
human body have many structures and organelles that move throughout them.
Cytoplasmic streaming is a way in which cells move molecular substances throughout the
cytoplasm, various
motor proteins work as
molecular motors within a cell and move along the surface of various cellular substrates such as
microtubules, and motor proteins are typically powered by the
hydrolysis of
adenosine triphosphate (ATP), and convert chemical energy into mechanical work.
Vesicles propelled by motor proteins have been found to have a velocity of approximately 0.00000152 m/s.
Particles According to the
laws of thermodynamics, all
particles of
matter are in constant random motion as long as the
temperature is above
absolute zero. Thus the
molecules and
atoms that make up the human body are vibrating, colliding, and moving. This motion can be detected as temperature; higher temperatures, which represent greater
kinetic energy in the particles, feel warm to humans who sense the thermal energy transferring from the object being touched to their nerves. Similarly, when lower temperature objects are touched, the senses perceive the transfer of heat away from the body as a feeling of cold.
Subatomic particles Within the standard
atomic orbital model,
electrons exist in a region around the nucleus of each atom. This region is called the
electron cloud. According to
Bohr's model of the atom, electrons have a high
velocity, and the larger the nucleus they are orbiting the faster they would need to move. If electrons were to move about the electron cloud in strict paths the same way planets orbit the Sun, then electrons would be required to do so at speeds that would far exceed the speed of light. However, there is no reason that one must confine oneself to this strict conceptualization (that electrons move in paths the same way macroscopic objects do), rather one can conceptualize electrons to be 'particles' that capriciously exist within the bounds of the electron cloud. Inside the
atomic nucleus, the
protons and
neutrons are also probably moving around due to the electrical repulsion of the protons and the presence of
angular momentum of both particles. == Light ==