Answer the Following Questions of Science of Ecliptic Plane Flashcards

Astronomical Unit is the average distance between the earth and the sun. The ecliptic plane is the flat plane in which we can define and observe the Earth's orbital path. And the axis tilt defines the direction in which the earth is oriented (towards a star called Polaris, or the North Star). This tilt is relative to the ecliptic plane and has no meaning in space where there is no up or down.

Because light takes time to travel to us through space. We observe things as they were when their light first began travelling towards us. A "snapshot' of a distant galaxy is a picture of both space and time.

Objects that lie within 14 billion light-years of Earth. Any light beyond has not had time to reach us since our universe is only 14 billions years old.

Stars, planets, moons, asteroids and comets can all be found within star systems, which may be found in galaxies white may be found in clusters of galaxies which may be found in superclusters, which exist int he universe which is the sum total of all matter and energy.

The disk of our galaxy contains the majority of visible stars, We reside in the disk about half way in, between the centre and the edge. However, the majority of mass in our galaxy is contained in the halo and are made up of dark matter.

Virtually ever galaxy outside the Local Group is moving away from us, therefore the space between galaxies is growing. Hubble was able to measure this through observing a galaxies Doppler shift.

1. Modern science seeks explanations for observed phenomena that rely solely on natural causes2. Science progresses through the creation and testing of models of nature that explain the observations as simply as possible (Occam's Razor)3. A scientific model must make testable predictions about natural phenomena that would force us to revise or abandon the model if the predictions do not agree with observations.

A hypothesis is an educated guess that has yet to be carefully tested and may change. A theory is supported by a large compelling body of evidence.

Speed tells us how far an object will go within a certain amount of time. Velocity tells us an objects speed and direction. Acceleration applies only when there is a change in velocity (i.e. speed or direction or both)

An objects momentum is a product of its mass and velocity. Force is the only way in which you may change an objects momentum.

Angular momentum is the circling or spinning of an object and can be defined as mass x velocity x radius. An object such as earth has both rotational and orbital angular momentum. Only a torque may change an objects angular momentum, as it is a "twisting force".

Mass measures the amount of matter in your body. Weight is dependent on your mass and on the forces acting on your mass (such as gravity).

1. An object moves at constant velocity if there is no net force acting upon it.2. Acceleration is dependent on an objects mass and the strength of it's net force. (force=mass x acceleration)3. For any force there is always an equal and opposite reaction force.

In accordance with Newtons first law of motion, any rotating or orbiting object will have a fixed acceleration as long as there is no torque acting on it. Therefore since angular momentum = m x v x r, an increase in radius must mean a smaller velocity in order to keep angular momentum fixed. An individual object may change its angular momentum by transferring some of it to another object. This is why the earth's orbital angular momentum stays fixed, why the earth orbits faster nearer the sun (radius decreases, velocity increases) and why it's rotational angular momentum is gradually slowing (transferring rotational angular momentum to the moon)

Energy cannot be destroyed or created. An object can gain or lose energy through exchange with other objects.