Structure of the Universe

Review: Red Shift/Blue shift

Red Shift/Blue shift According to the example of the plane, when sound waves are in front of the plane they become compressed creating a high frequency sound. The sound waves behind it stretch creating a lower frequency sound.  Light ALSO travels in waves. Light waves are able to compress and stretch thereby changing their frequency.

Is wavelength shorter or longer Complete the Table Type of Shift Draw the Wavelength Direction of Movement Is wavelength shorter or longer Redshift    Away  longer Blueshift  toward  shorter When objects are moving away from us we say they are RED SHIFTED When objects are moving toward us we say they are BLUE SHIFTED

Dark Energy/Dark Matter

Dark Matter You, trees, planets, and the distant stars account for less than 5 % of the known universe. 25% is dark matter and 70% dark energy. Both dark energy and dark matter are invisible. Dark matter is the stuff that makes it possible for galaxies to exist. The gravity of the visible matter is not strong enough to form galaxies and complex structures, the stars would more likely be scattered all over the place. We know something else exists that doesn’t emit or reflect light. Places with a high concentration of dark matter, bend light while passing by. So we know that something interacts with gravity.

We know 3 things for sure: We have more ideas about what dark matter is NOT than what is. It is NOT: Just clouds of normal matter without stars Anti-Matter Not made up of black holes We know 3 things for sure: Something is out there. It interacts with gravity There is a lot of it.

Dark Energy DARK ENERGY is more mysterious We can’t detect it We can’t measure it We can’t taste it Dark energy seems to be some kind of energy intrinsic to empty space. The energy is stronger than anything we know and keeps getting stronger as time passes by.

We have multiple ideas as to what dark energy might be. Idea 1: Dark energy is not a thing but just a property of space. Idea 2: Empty space is actually full of temporary virtual particles that spontaneously and continually form from nothing, then disappear into nothing again Idea 3: An unknown kind of dynamic energy fluid or field which goes through the universe but somehow has the opposite effect