1.3 Spaceship Earth

Front 1

What are rotation and Orbit?

Back 1

These are the most basic motions of earth. The rotation is the spinning of earth(day) and Orbit is it's yearly revolution around the sun.

Front 2

What is the axis of earth?

Back 2

The acis is the imaginary line connecting the North Pole to the South Pole. Earth rotates counter clockwise as viewed from above the NP. This is why the stars rise in east and set in the west.

Front 3

What is the average distance the earth travels each year?

Back 3

The average is one astronomical unit which is about 150 million Kilometers.

Front 4

How fast are we racing around the sun? Why can't we feel it?

Back 4

We are moving 100,000 kilometers per hour, 60000 miles per hour.

Front 5

What is the ecliptic plane? What is the axis tilt?

Back 5

The earth's orbital path that defines a flat plane.
The earth is tilted by 23 1/2 to for a line perpendicular to the ecliptic plane. It is oriented so that the axis points almost directly at the star called polaris or the north star.

WIkipedia: The Earth's orbital plane is known as the ecliptic plane, and the Earth's tilt is known to astronomers as the obliquity of the ecliptic, being the angle between the ecliptic and the celestial equator on the celestial sphere.

Front 6

In which direction does earth orbit the sun? In which direction does earth rotate?

Back 6

Counterclockwise!

Front 7

At what speed do stars orbit the galactic centre?

How does this contribute to our understanding of mass distribution of the galaxy?

Back 7

stars differ in speeds. we can learn how mass is distributed by measuring these speeds.

Front 8

What is dark matter?

Back 8

Unclear. It is not viewable by teelscope. it is compleatly invisable by telescope. the galaxctic center or disk is seemingly made up of dark matter but it appears most of the galaxy mass is located outside of the galactic disk.

Front 9

Edwin Hubble-- what tow facts can we attribute to him? what are his contributions?

Back 9

Virtually every galaxy outside of our local group is moving away from us.

The further the galaxy is from us the faster it appears to be racing away. expansion.

Space is growing between galaxies or clusters of galaxies.

Front 10

why do more distant galaxies move faster away from us then closer galaxies?

Back 10

because gravity of closer galaxies keep them together. further galaxis are being carried away by the expansion of space.

Front 11

Doppler shifts

Back 11

illustrate how modern astronomy depends both on careful observations and on using current understanding of the laws of nature to explain what we see. The Doppler effect (or Doppler shift) is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. Radar?