astronomy class lecture

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