Book contents
- Frontmatter
- Dedication
- Contents
- Preface
- Acknowledgements
- 1 Watchers of the skies
- 2 Our Sun
- 3 Aspects of our Solar System
- 4 The rocky planets
- 5 The hunt for Planet X
- 6 Voyages to the outer planets
- 7 Harbingers of doom
- 8 Impact!
- 9 Four hundred years of the telescope
- 10 The family of stars
- 11 Aging stars
- 12 The search for other worlds
- 13 Are we alone? The search for life beyond the Earth
- 14 Our island Universe
- 15 Wonders of the southern sky
- 16 Proving Einstein right
- 17 Black holes: no need to be afraid
- 18 It’s about time
- 19 Hubble’s heritage: the astronomer and the telescope that honours his name
- 20 The violent Universe
- 21 The invisible Universe: dark matter and dark energy
- 22 The afterglow of creation
- 23 To infinity and beyond: a view of the cosmos
- Index
- Plate section
- References
14 - Our island Universe
Published online by Cambridge University Press: 05 October 2014
- Frontmatter
- Dedication
- Contents
- Preface
- Acknowledgements
- 1 Watchers of the skies
- 2 Our Sun
- 3 Aspects of our Solar System
- 4 The rocky planets
- 5 The hunt for Planet X
- 6 Voyages to the outer planets
- 7 Harbingers of doom
- 8 Impact!
- 9 Four hundred years of the telescope
- 10 The family of stars
- 11 Aging stars
- 12 The search for other worlds
- 13 Are we alone? The search for life beyond the Earth
- 14 Our island Universe
- 15 Wonders of the southern sky
- 16 Proving Einstein right
- 17 Black holes: no need to be afraid
- 18 It’s about time
- 19 Hubble’s heritage: the astronomer and the telescope that honours his name
- 20 The violent Universe
- 21 The invisible Universe: dark matter and dark energy
- 22 The afterglow of creation
- 23 To infinity and beyond: a view of the cosmos
- Index
- Plate section
- References
Summary
The Milky Way
On a dark night with transparent skies, we can see a band of light across the sky that we call the Milky Way. (This comes from the Latin − Via Lactea.) The light comes from myriads of stars packed so closely together that our eyes fail to resolve them into individual points of light. This is our view of our own galaxy, called the Milky Way Galaxy or often ‘the Galaxy’ for short. It shows considerable structure due to obscuration by intervening dust clouds. The band of light is not uniform; the brightness and extent is greatest towards the constellation Sagittarius, suggesting that in that direction we are looking towards the Galactic Centre. However, due to the dust, we are only able to see about one-tenth of the way towards it. In the opposite direction in the sky the Milky Way is less apparent, implying that we live out towards one side of the Galaxy. Finally, the fact that we see a band of light tells us that the stars, gas and dust that make up the Galaxy are in the form of a flat disc (Figure 14.1).
A detailed image of the centre of the Galaxy in the constellations Sagittarius and Scorpius is shown in Figure 14.2.
- Type
- Chapter
- Information
- A Journey through the UniverseGresham Lectures on Astronomy, pp. 192 - 208Publisher: Cambridge University PressPrint publication year: 2014