George Hrab and the 365 Days of Astronomy Podcast
Astronomy Class Lecture
Jun 26, 2015
This is the second lecture from my Life Beyond Earth class in 2010. Note: the class was 2 hours long.
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George Hrab and the 365 Days of Astronomy Podcast
The Universe (in one lecture)
Lecture 2Chapter 3.1, 3.2, 3.4
The Size and Scale of Things
in HD (local file)
By morn1415 on YouTube
The Size and Scale of Things
Scale Model in Green Bank, WV Voyage Model in DC – Jeffrey Bennett
The Size and Scale of Things
If the Earth is the size of a ping pong ball, how big is the Sun?
CC Watchcaddy on Flickr
The Size and Scale of Things
If the Earth is the size of a ping pong ball, how big is the Sun?
Ping pong = 40 mm diameterDiameter Sun = 109 * Diameter of EarthAnalog sun ->
CC Watchcaddy on Flickr
The Size and Scale of Things
If the Earth is the size of a ping pong ball, how big is the Sun?
Ping pong = 40 mm diameterDiameter Sun = 109 * Diameter of EarthAnalog sun -> ~ 14.3 ft diameter
about the size of this room!
CC Watchcaddy on Flickr
The Size and Scale of Things
How far away is the ping pong ball from the room?
The Size and Scale of Things
How far away is the ping pong ball from the room?
Our scale: ~1:160,000,000Distance from Earth to Sun ~ 93 million milesModel distance ->
The Size and Scale of Things
How far away is the ping pong ball from the room?
Our scale: ~1:160,000,000Distance from Earth to Sun ~ 93 million milesModel distance -> ~3081 ft, or the distance to
the Rotunda
The Size and Scale of ThingsSun Earth
The Size and Scale of Things
Mercury Venus Mars
Sun Earth
The Size and Scale of ThingsJupiterto Mars Saturn
Uranus Neptune Outer Edge of Kuiper Belt
The Size and Scale of Things
2:37 Sixty Symbols on YouTube Local HD
The Size and Scale of Things
Now, pretend the Sun is a ping pong ball. Where is the nearest star?
MSX/IPAC/NASA
The Size and Scale of Things
Now, pretend the Sun is a ping pong ball. Where is the nearest star?
Alpha Centauri (3 star system) 4.2 light years or 1.3 parsecs away2.5 x 1013 miles (25,000,000,000,000 miles)
The ping pong ball would be ->
MSX/IPAC/NASA
The Size and Scale of Things
Now, pretend the Sun is a ping pong ball. Where is the nearest star?
Alpha Centauri (3 star system) 4.2 light years or 1.3 parsecs away2.5 x 1013 miles (25,000,000,000,000 miles)
The ping pong ball would be -> 714 miles away
MSX/IPAC/NASA
The Size and Scale of Things
Ping pong ball Ping pong ball
The Size and Scale of Things
Those are just two nearby ping pong balls in a group of 100 billion, spanning millions of miles
… a galaxy spanning thousands of light years, or hundreds of quadrillions of miles!
Nick Risinger
HOW do we know?
• Distance to Venus -> radar– The ratios of planetary distances were known, but
an accurate measurement to Venus using the speed of light solidified the numbers
NASA NASA
HOW do we know?
• Nearby stars measured by parallax
CC NoisyAstronomer
HOW do we know?
• More distant objects use indirect methods, building a “distance ladder”– Star spectral types– Variable stars– Supernovae– Redshift
Ned Wright
DOE NNSA ASC/Alliance Flash Center at U of Chicago
The Universal Context
The Millenium Simulation (http://www.mpa-garching.mpg.de/galform/millennium/)
local local better
The Universal Context
Sloan Digital Sky Survey
The Universal Context
Tree Lobsters are awesomeMore Perspective
Expansion
Elementary, my dear Humason!
The further away a galaxy is, the faster it is moving away! Beautifully demonstrated by distant supernovae all the way to large distances measured today.
Expansion
NASA
More Evidence of Expansion
WMAP/NASA
CMB in Context
More Evidence of Expansion
http://casa.colorado.edu/~ajsh
H, He, Li… boring universe?http://savillbiology.com/Chemistry.html
Star Stuff…
All of Cosmos is available for free on Hulu. Seriously, watch it: http://www.hulu.com/cosmos
Csemisery on Youtubelocal
Stellar Life Cycle
Molecules in Space
Orion Nebula, NASA/Herschel
Other Solar Systems
Beta Pic, ESO
Other Solar Systems
Fomalhaut b, HST/NASA
Other Solar Systems
There’s an app for that
How do we know?
It’s all about LIGHT.
Chandra and STSci
It’s all about LIGHT
Temperature and Light
Planets and People(300 K)
Stars(1000s K)
Masgatotkaca (Wikimedia)
Hubble, NASA
Atoms (and molecules) and Light
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