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OUR AMAZING SUN

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OUR AMAZING SUN (Alexandria, March 26, 2006) Eric Priest INTRODUCTION Ancient Egyptians Aten Eye of Ra or Horus Tutankhamun s throne Why Study the Sun ? – PowerPoint PPT presentation

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Title: OUR AMAZING SUN


1
OUR AMAZING SUN
(Alexandria, March 26, 2006) Eric Priest
2
INTRODUCTION
For centuries we have worshipped the Sun
3
Ancient Egyptians
Many forms of Sun worship
Ra or Re - the Sun god (old kingdom)
4
Aten
- the visible disk or face of the Sun
5
Eye of Ra or Horus
(-- eclipse) reflects solar energy, reason
mathematics
6
Tutankhamuns throne
  • King bride
  • rays of Aten sun-disk
  • protecting
  • giving them life

7
Why Study the Sun ?
1. Of great scientific interest in own
right
2. Influence on Earth
3. Important for Astronomy
-- fundamental cosmic processes
But -- Many basic properties still a mystery
So Sun is 1 of liveliest branches of astronomy
8
Traditionally
close link Mathematics - Astronomy
To construct pyramids, Egyptians had outstanding
grasp of both
e.g., Gregory Chair of Maths James Gregory
(1638-1675)
Invented Reflecting Telescope
Co-founder of Calculus
9
James Gregory
  • Elected FRS (Academician) 1668 (age 30)
  • Appointed 1st regius prof maths at St Andrews
    (1668)
  • Given hall as lab -- see line for telescope
    along meridian

10
OUR AMAZING SUN
(Theme Sun full of surprises)
CONTENT
1. Introduction 2. Structure of the Sun
3. Sunspots 4. Corona
5. Modern Surprises - SOHO satellite
Solar Flares and CME's Conclusions
11
Another Theme
Many surprises caused by magnetic field (B)
Sun is plasma --gt coupled (intimate, subtle)
to B
B exerts force on plasma -- stores energy
12
MOST of UNIVERSE is PLASMA
Ionosphere --gt Sun (8 light mins)
  • stars (4 light years)
  • At 186,000 miles per sec

13
MOST of UNIVERSE is PLASMA
Ionosphere --gt Sun (8 light mins)
Learn basic behaviour of plasma from Sun
14
2. STRUCTURE of SUN
Vital Statistics
Radius
100 x Earth 700 Mm (1Mm 1000 km)
Ball of gas held together by gravity
15
Overall Structure
Interior Core Convection zone (gt 0.7 R0)
Atmosphere Photosphere, Chromosphere, Corona
16
Best ever images
Photosphere
Movie
Zoom from full disk
Movie
Covered with turbulent convection cells
Granulation (1 Mm)
by factor 100 to 70 km resolution
17
3. SUNSPOTS
Thomas Harriot discovered (1610) w.
telescope Galileo
-- Greeks, Chinese
18
Surprise (1908)
site of strong magnetic field
Dark because cool But why cool ?
Because magnetic field (B) stops granulation
19
Stunning Image
Penumbral structure created by B
Scharmer van der Voort
20
Map of Photospheric Magnetic Field
White -- towards Black -- away
Around sunspots -- bipolar "Active Regions"
21
Movie
Intense magnetic fields over whole Sun
Movie
B carried to edges of convection cells
22
Chromosphere -- very dynamic
Simulation HansteenCarlsson
Corona
t. region
Movie
Chromor
Photor light/ dense.
23
4. CORONA
("crown") -- See at ECLIPSE of Sun
Faint open structures -- Bright closed structures
SURPRISE (1868) -- Light from new element "Helium"
SURPRISE (1940) -- Temperature is million degrees
!!!!
24
Another ECLIPSE
Structure created by B
In corona B dominates plasma
heats plasma
25
Eclipse path
26
Iran 1999(Koutchmy-- see tomorrow)
Radial structures outflow --solar wind
Research students imaginative
27
CORONA
Normally need eclipse to see -- Glare of surface
Observe direct with X-ray telescope
As T increases (furnace), object becomes bluer
28
Picture with X-ray telescope
Leon Golub (tomorrow) - pioneer
Image from latest new satellite
29
Close-up of Magnetic Loops (Active region)
30
From the Side in Corona (TRACE)
- creates intricate structure
B strong
- dominates plasma
31
5. SOHO (Solar Heliospheric Observatory)
Launched 1995. Orbiting Sun in phase with Earth
Observing Sun continuously for 1st time (ESA/NASA)
--gt 1st comprehensive view of Sun
MANY NEW SURPRISES
32
The SUN this week
Photo sphere
33
Magnetic Field
34
Corona at 1.6 MK
35
Corona at 2.0 MK
36
QN. -- ? How Do Flares CMEs Occur
SOHO Coronagraph -- Artificial eclipse
Discovered huge ejections of plasma
Can reach Earth - communications / satellites
37
On October 28, 2003
Photo- sphere from SOHO
3rd largest flare
38
Outer Corona from SOHO
CME 2000 km/s (5 times faster than normal)
Snow -- relc particles
39
Thurs
Aurora in St Andrews
40
1 Week Later (Nov 4 )- Fireworks Continued
the biggest solar flare ever recorded !
41
Close-up from TRACE
Movie of flare at limb
Movie of zoom in and out
42
6. CONCLUSIONS
  • Ancient egyptians intrigued by Sun -- continues
  • Solar Physics - golden age - space observations
  • Sense of vitality will continue

43
Future Space Missions
STEREO July 2006 Two satellites Stereo
images of corona
Solar B (Japan-US-UK) Sept 2006 Connections
surface/corona
Solar Dynamics Observatory 2008 Successor to
SOHO
Solar Orbiter (ESA) 2015 3 times closer than
Mercury
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