Our Galaxy and Beyond

Our Place in Our Galaxy

3 What’s the Difference? Universe Galaxy Image credits: NASA, STScI Solar System

4 What’s the Difference? Universe Galaxy Solar System

5 Where is our Solar System? Visible stars, gas, dust in the Milky Way Galaxy Image credits: NASA, STScI Solar System here

6 How big is the Milky Way Galaxy? 100,000 light years Image credits: NASA, STScI

7 How far is 100,000 light years? 1 inch represents 5.5 light hours (Sun to Pluto) 1 mile represents 40 light years 2,500 miles represents 100,000 light years

8 2,500 miles Continent of North America!

9

10 And how thick is our Galaxy? Credit: NASA, COsmic Background Explorer (COBE) Project ~1000 light years

11 How thick is 1,000 light years? If 2,500 miles represents 100,000 light years 25 miles represents 1,000 light years

BILLION Stars!!!

13 Fill with bird seed 4 feet deep on a football field 200 BILLION Stars!!!

2,500 miles Spread them over the continent 25 miles deep!

16 What’s in our Universe Objects in our Solar System –Sun –Planets Objects in our Galaxy (The Milky Way) –Star Systems –Black hole –Nebulae –Stars –Globular clusters of stars Objects in our Universe…

17 Black Hole Space Warp In groups –Have two people hold the hoop horizontally. –Place the weight at the center of the hoop. –Have two people slowly toss in the bouncy balls one at a time. Toss them so that they are near the edge of the hoop when you release them. –Observe what happens to the path and the speed of the balls. –Repeat this 3 times.

18 Black Hole Space Warp In your booklet answer the following questions based on your observations. 1.What do the moving balls represent? 2.What does the weight represent? 3.What happened to the balls? 4.What does the blue latex material represent? 5.What happens to the material when the bouncy balls roll around?

19 Monstrous black holes At the heart of every galaxy lies a black hole, millions to billions times the mass of our Sun HST/NGC light years

20 The Black Hole at the center of the Milky Way

21 Masses of Black Holes Primordial – can be any size, including very small (If <10 14 g, they would still exist) “Stellar mass” black holes – must be at least 3 M o (~10 34 g) – many examples are known Intermediate black holes – range from 100 to 1000 M o - located in normal galaxies – many seen Massive black holes – about 10 6 M o – such as in the center of the Milky Way – many seen Supermassive black holes – about M o - located in Active Galactic Nuclei, often accompanied by jets – many seen