Topic 3 – Earth in the Universe

What makes up the universe and how old is it? The universe is made up of everything that exists in any place. This includes all space, matter and energy. The universe is approximately between billion years old.

What is a celestial object? A celestial object is any object outside or above the Earth’s atmosphere.

How was the universe created? Many scientists believe the universe was created by a BIG BANG. This theory states that all matter and energy started out concentrated in a small area, after a gigantic explosion, matter spread out and reorganized as subatomic particles and atoms.

What is electromagnetic energy? The electromagnetic energy is energy that is transmitted in the form of waves, that travel through space. These waves can be compared to sound waves because they travel in similar patterns. The visual portion of the waves that we see is the rainbow.

Properties of Waves A wavelength is the distance from one crest to the next crest or one trough to the next trough. Frequency refers to “how often” something occurs. When relating frequency to waves, it means how many times a wave passes a particular point in a given amount of time. (ex: how many ocean waves crash on the shore in one minute.) Waves with a high frequency will have a high pitch(sound). Waves with a low frequency will have a low pitch (sound).

How is the creation of the universe justified? Evidence for the creation of the universe is: 1) Long-wavelength radiation - usually microwaves that appear to be coming from all directions in the universe. 2) Shifting of wavelengths – scientists have studied radiation emitted by stars. Each element emits energy in different portions of the electromagnetic spectrum (ESRT pg. 14). Comparing these spectrums, to spectrums of the same element on Earth, scientists have found that the wavelengths (or colored lines) are shifted.

What is the Doppler Effect? Named after an Austrian mathematician and physicist, Christian Doppler. The Doppler Effect is the shifting of wavelengths (refer to previous slide) – first discovered with sound. Wavelengths are either shifted to a shorter wavelength (color blue) or to a longer wavelength (color red).

How many types of the Doppler Effect exist? There are two types: 1) Red Shift (most common) – occurs when two objects are moving apart from one another, the electromagnetic waves spread out, wavelength increases. 2) Blue Shift – occurs when two objects are moving toward one another, the electromagnetic waves bunch up, wavelength decreases.

In what ways do these two types differ? The two types differ by: 1) Wavelength a)Red shift, wavelength is longer b)Blue shift, wavelength is shorter 2) Pitch a)Red shift, lower pitch b)Blue shift, higher pitch 3) Movement a)Red shift - moving away b)Blue shift - moving toward

What are some examples of the Doppler Effect? A car moving past you Sound of a train when you are on a platform An ambulance moving past you. As the ambulance approaches, the sound waves from its siren are compressed towards the observer, creating a higher pitch. As the ambulance moves away, the sound waves are stretched relative to the observer, creating a lower pitch. Doppler Effect #1 Doppler Effect #2

How does the radiation we receive exhibit the Doppler effect and what does this mean? Most wavelengths we receive from all other matter in the universe are red shifted. Overall, this mean that objects are moving away from one another and the universe is continually expanding.