1. The Dynamics of Visible Objects in the Universe
New Core Curriculum
week 4, class-1
Foundations of Scientific Process
The Dynamics of Visible Objects in the Universe

3. How do we measure distance of these objects ?

4. Distance Measure  a) Laser beam + mirrors
Earth-Moon distance was determined

5. Stellar Parallax Distance to star = 4.4 ly D/d = angle (in radians)
Distance Measure  b) Parallax
Stellar Parallax
D/d = angle (in radians)
Text
.7”
d(istance)
Distance to star = 4.4 ly D
biased for “near-by” objects

6. How do we know the dynamics of these objects ?

7. Doppler effect Phenomenon exhibited by a moving source of light:
Blue shift
You might wish to review waves/wavelengths here as well.
Red shift
Which direction is the wave source moving?

8. Limitation: wavelength shifts are tiny
Doppler Shift Method:
Limitation: wavelength shifts are tiny

9. star wobbles in response to planet orbiting it
Doppler Shift Method:
example:
star wobbles in response to planet orbiting it
observer

10. Doppler Shift of light “- v”: TOWARD the observed
wavelength stretched  object moving away the observer
wavelength compacted  object is moving towards the observer
400 nm
800 nm
Emitted Star Light
(intrinsic)
Red Shift
Receding
Observed Star Light
(detected)
“- v”: TOWARD the observed
“+v”: AWAY from the observed

12. - what is an orbit!!!! Students don’t get this....

14. “Galaxy Crash” can be loaded from the following website:
select option “applet” and then you can specify some parameters of the 2 galaxies whose interactions you would like to model

15. The Dynamics of Visible Objects in the Universe
Key Concepts for Week-4, Class-1:
(what You need to know, as You will be tested on this material):
Term “Proxy”
Proxy for distance (mirrors & laser light, parallax)
Proxy for velocity (Doppler Shift Method)
Doppler Shift Phenomenon / Method
Blue shift (moving towards) & Red shift (moving away)
Atomic line spectrum (atomic fingerprint) as an aid for applying Doppler Shift Method
Value of Models in Astronomy