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The Sun and Life on Planets by Saku Tsuneta

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Solar activities and magnetic fields affect: are they important for us rather than a mere astronomical fact?

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The Sun and Life on Planets Hinode X-ray Sun in 2007 Saku Tsuneta Institute of Space and Astronautical Science (ISAS) Japan Aerospace Exploration Agency (JAXA) 2016 September 5 “Science of the Cosmos, Science in the Cosmos” BBVA Foundation, Madrid
Today’s talk • Sunspots and magnetic fields of our Sun • Is the Sun about to run out of sunspots? • Global warming or cooling? • Planetary magnetic fields: a protector for life • Super flares: hazards for life and civilization • Could a second Earth harbor life?
Sunspot
EUV Imaging Spectrometer（EIS） Observe plasma temperature & motion Solar Optical Telescope（SOT） High spatial-resolution magnetic field observations X-ray Telescope （XRT） 1-10MK X-ray corona How… … is the magnetic field created? … is the corona heated? … do explosions (solar flares) occur? … is the supersonic solar wind accelerated? 3 well-coordinated advanced telescopes. Orbit: Polar Sun Synchronous JAXA-NASA-UK-ESA Hinode
Closer and closer to the sun, you begin to see granulation (convection cell)
Closer and closer to the sun, you begin to see granulation (convection cell)
Closer and closer to the sun, you begin to see granulation (convection cell)
Closer and closer to the sun, you begin to see granulation (convection cell)
Closer and closer to the sun, you begin to see granulation (convection cell)
Closer and closer to the sun, you begin to see granulation (convection cell)
Japan Sunspot!
Sunspots have strong magnetic fields Magnetic field line X-ray image of the Sun
How strong is the magnetic field of a sunspot? • Sunspot magnetic field is 1000-3000 Gauss. Magnetic field inside the Sun is about 100,000 Gauss! North pole South pole Earth: 0.5 Gauss Milky Way: 0.000001 (one millionth) Gauss Bar magnet：2500 Gauss magnetic wall plaster：800 Gauss
Rotation of the Sun Convection inside the Sun Origin of Magnetic fields Kinetic Energy Magnetic Energy Dynamo Coronal heating Solar flares reconnection waves
Magnetic fields emanating from inside the Sun
Photosphere and dynamic chromosphere Quiet Photosphere (430nm) Active Chromosphere (396nm) Sunspot
Different outlook: Corona seen in X-rays（1-10MK）
Prominence sustained by magnetic fields
First observation of solar polar region by Hinode
How can we see the polar region? • Sun’s axis is tilted 7degree from the Earth’s orbital plane • In March, we can glimpse the Solar South pole. September is a good season to observe North pole. 7 degree Earth location in September Earth location in March Orbital plane of the Earth Rotation axis Observing region in September Observing Region in March
Reversal of polar field every 11 years Year 1997 Year 2008 Magnetic map (ESA SOHO) White/blue：plus polarity Black/orange : minus polarity + -+ -
Magnetic field around the Sun’s poles Sep. 2012 Sep. 2013 Sep. 2014 Sep.2015 Mar. 2013 Mar. 2014 Mar. 2015 Mar.2016 North Polar Region South Polar Region
Year 2008 Year 2012-13 At maximum sunspots, the polar fields were thought to flip together. But, Hinode found that the North pole reversed first, producing a quadrapole. South PLUS South PLUS North PLUSNorth MINUS
How anomalous is the Sun now?
Persistent and continuous observations of sunspots for 400 years Galileo Galilei (1612) National Astronomical Observatory of Japan (NAOJ, Tokyo, 1998) NAOJ, solar observatory 400 years of continuous observations
Few sunspot between 1645～1715 Solar dynamo stopped? Frozen Thames Number of sunspots increases & decreases on 11 year cycle. Drastic decrease in sunspots observed between 1645-1715. Cold period coincides with the Maunder minimum Maunder minimum Dalton minimum Calendar year Sunspotnumber
NAOJ, Solar Observatory Unusually long solar-cycle period Launch of Hinode Red line Current cycle Black lines：past 6 cycles overlaid, starting at the minimum.
Unusually long solar-cycle period Cycle length 12.6 year! Nominal cycle length 11 year NAOJ, Solar Observatory
13.2yr 12.6yr 9.7yr 10.7yr 9.9yr ??yr Increasing sunspot cycle period
Similar long period found 200 years ago Calendar year Sunspotnumber
How do we observe sunspots on the ancient Sun? Higher solar activity ⇒ Decreases cosmic rays entering Earth’s atmosphere ⇒ Decrease in carbon-14 ⇒ Decrease recorded in tree rings Earth Heliosphere (magnetic fields) Cosmic rays (a) Sun’s magnetic field hinders cosmic rays entering the solar heliosphere Nitride nucleus (b) Cosmic rays bombard Earth’s atmosphere to generate Carbon-14 Carbon cycle Carbon dioxide（14CO2 ） Recorded in tree ring via photosynthesis proton Atmospheric atoms carbon14 Neutron Carbon-14 6 protons and 8 neutrons
Blue dots: Miyahara et al., 2004, 2006, 2007, 2008 Red dots: Damon, 2003 Black curve (decadal): Stuiver et al., 1998 (Decadal) MaunderSpoerer Wolf Dalton Oort ~9yr 11~13yr 10~11yr 9~11yr 13~14yr ~14yr ~13yr D14C(permil) ~11yr -30 -10 10 30 800 1100 1400 1700 2000 Year AD Higher solar activity Lower solar activity Lower solar activity is accompanied by longer cycle time and vice versa
How do we predict future solar activity?
Dynamo process inside the Sun (current paradigm) Polar magnetic fields are the source of sunspot magnetic fields. Indicate future solar activity. Faster equatorial rotation (differential rotation) N S Magnetic field line* N S N S Emerged fields seen as sunspot pair *Magnetic fields behave like rubber tube Amplified Magnetic fields
Rapid weakening of solar magnetic field North Pole South Pole Wilcox Solar Observatory Royal Observatory of Belgium Polar Magnetic Field Sunspot Number Year Year Cause Effect Magnetic field polarities flip during the solar maxima periods
Cycle period～14yr Cycle period～13yr Cycle period～13yr Is the Sun entering a stagnant period? Asymmetric polarity Sunspot only in south pole (asymmetric polarity)
now 11400 years ago 4000 years ago Sunspot number upto 11400 years ago The latest grand maximum started in mid-20 century and ended with the start of new century.
From NASA D. Hatraway http://solarscience.msfc.nasa.gov/predict.shtml 2016 July 2030 Cycle 25 2025-26? SSN=50? 2040 Prediction of future sunspot number Cycle 24 (SSN=113 in 2014) the lowest since Cycle14 in 1905 (SSN=105)
Does sunspot number affect the Earth?
British Met Office announcement February 2015 In the last 15 years, global surface warming has slowed, despite increases in greenhouse gas emissions. (http://www.metoffice.gov.uk/research/news/2015/vari ations-rate-global-warming)
The cherry tree historical climate monitor • Temperature determines when cherry trees flower; hotter weather leads to earlier flowering, and vice versa. • Using 822 years of historical records on cherry-blossom viewing parties etc, the past 1200 years of temperatures in Kyoto in March were reconstructed. • Data taken between 1911 – 1940 was used to calibrate, confirming prediction accuracy of 0.1°C. Aono (2012)
Conversion of Japanese lunar calendar to modern Gregorian calendar Kyoto: capital of Japan from 794 to 1868 In diaries, chronicles, poems on flowering, viewing parties, events such as gifts to the Emperor are depicted by Emperors, aristocrats, politicians, monks, and merchants. 平 松 時 庸 記 寛 永 廿 一 年 三 月 八 日 （西 暦 一 六 四 四 年 四 月 十 四 日 ） Obtain full-flowering dates of cherry tree (Prunus jamasakura) Prof. Y. Aono, Osaka Prefecture University 於 清 涼 殿 花 御 覧 天 盃 頂 戴
Low temperature periods coincide in lower solar activity period Temperature decreases occur close to end of solar minimum. (delay in a few tens of years) Reconstructed temperature and solar activity 10th century warmer than now Aono (2012) Marchmean temperature Full-flowering dates(DOY) Reconstructed Sunspotnumber after removing heat island effect Averaged reconstructed temperature red: 95% confidence level
Frozen Thames (1677) http://en.wikipedia.org/wiki/File:The_Frozen_Thames_1677.jpg
-4000 -3000 -2000 -1000 0 1000 2000 0 20 40 60 Sunspotnumber Years -BC/AD Sunspot number (Usoskin et al., 2007) and cold/wet conditions in Europe (Versteegh, 2005) over 6500 years: 14 cold spells vs 15 Grand minima  12 coincide. Courtesy of Ilya G. Usoskin Cold spells vs. Grand solar minima
⇐1degree C drop ⇐2 degree C drop Temperature decrease during Maunder minimum in Kyoto What would happen if we enter a Maunder minimum?
How do planetary magnetic fields protect life and civilization?
Sun 48 Shock waves and coronal mass ejection from the Sun propagate toward the Earth in solar wind stream Earth Earth
Negative effect of disturbance Quebec blackout (1989)Aurora Satellites and GPS malfunction, radiation hazard
Magnetic fields of planets Earth Saturn Jupiter Venus Mars Mercury Direct interaction between Planetary atmosphere and solar wind Formation of strong protective magnetosphere weak strong Photos©NASA
Magnetic fields of planets Earth Saturn Jupiter Venus Mars Mercury Direct interaction between Planetary atmosphere and solar wind Formation of strong protective magnetosphere weak strong Photos©NASA ×1/100 ×1 ×600 ×20,000 No magnetic field Small fossil magnetic field
Planets and magnetic fields Jupiter Mars Earth VenusMercury Saturn Uranus Neptune
Stripping away ancient Martian atmosphere due to intense solar storm • Weak gravity struggles to hold the Martian atmosphere. • Mars lost its own magnetic fields in ancient times. • Young Sun emits intense UV and X-rays. • Initial rich Martian atmosphere may be lost due to intense solar storms.
Earth fortunately has a magnetic field…
Mars does not have any magnetic field… Mars
Humans outside our magnetic field • The Apollo moon missions travelled beyond the Earth’s magnetosphere. • Apollo astronauts showed a greater risk of cardiovascular disease (CVD). • CVD mortality among Apollo astronauts was almost 5 x that of non-flight or ‘low Earth orbit’ astronauts. • The Earth’s magnetosphere protects humans! Delp, M. D. et al. Apollo Lunar Astronauts Show Higher Cardiovascular Disease Mortality: Possible Deep Space Radiation Effects on the Vascular Endothelium. Sci. Rep. 6, 29901 (2016).
Do exoplanets harbor life?
 なぜ第2の地球を探す？  系外惑星発見前夜  太陽系は標準でない？  すばるにおける惑星探し  ハビタブル惑星とは？  宇宙における生命• 100 billion stars in one galaxy • 100 billion galaxies in universe • In total, 10000000000000000000000000 stars! Big Questions in space science 1. How did life emerge on Earth? 2. Does a second Earth exist? 3. Do extra-terrestrial life-forms exist? 4. What is dark matter and dark energy? 5. How did this universe begin and form?
The Sun and Life on Planets by Saku Tsuneta
The Sun and Life on Planets by Saku Tsuneta
Fraction of stars with at least one planet (period < 85 days) Small 17% 21% 20% 2% 2% Total=62%
The Sun and Life on Planets by Saku Tsuneta
３ 将来の展望  If the following materials in the atmosphere are detected, life may exist.  Water  Ozone(oxygen)  Carbon dioxide  Methane  NASA WFIRST・ESA-JAXA SPICA missions are expected to detect these! Spectra of planetary atmosphere Wavelength(micron)Temperature(K) Venus Gelileo （Sagan1993） Can species on other planets guess we are here? Water Ozone Carbon dioxide Earth Mars
How do super flares affect life and civilization on Earth and other planets?
Occurrence rate of big solar flares (GOES classification in terms of X-ray intensity) Number of Solar Flares year X M C • ---------------- • 1989 59 620 1929 • 1990 16 273 2262 • 1991 54 590 2653 • 1992 10 202 1922 • 1993 0 74 1142 • 1994 0 25 336 • 1995 0 11 148 • 1996 1 4 81 • 1997 3 21 286 • 1998 14 94 1188 • 1999 4 170 1854 • 2000 17 215 2223 • 2001 21 310 2101 C-class flares 1000 events per year M-class flare 100 events per year X-class flare 10 events per year X10-class flare 1 event per year Ｘ100-class flare every 10 years X100000-class flare every 10000 year Every 10 times increase, Occurrence rate one 10th X-class solar flare Soft X-ray intensity
Largest flare ever observed: Carrington flare(1859, Sep 1, am 11:18 ） • Richard Carrington in 1859: first record of flare observation • Very bright aurora appeared next day in Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii. • Total energy: 1032erg • Estimated to be the largest magnetic storm (> 1000 nT) in modern history • Telegraph systems all over Europe and North America failed. • Telegraph pylons threw sparks and telegraph paper spontaneously caught fire（Loomis 1861） • The solar storm (flare) on 2012 July 23 observed by STEREO is supposed to be a super- Carrington class, though it occurred on the invisible side of the Sun from the Earth • If it hit the Earth, the estimated economic impact is estimated to be >$2 trillion
A super flare recorded in Japanese cedar trees 1035erg super flare? （1000 times larger than the largest flare ever observed） (Miyake et al. Nature , 2012, June, 486, 240) Nature
Superflare 10000 times larger than the largest solar flare Maehara et al. (2012) Super flare: Total energy~1036 erg 10000 times larger than the largest solar flares Maehara et al. (2012) Sun Super flares Intensity(visiblelight) Day A star with a big star spot generates super flares
Superflare C M X X10 X1000 X100000 Shibataetal.2013 1000 in 1 year 100 in 1 year 10 in 1 year 1 in 1 year 1 in 10 year 1 in 100 year 1 in 1000 year 1 in 10000 year Comparison between solar flares and superflares Largest solar flare Superflares 1000 times more energetic than the largest solar flares occur once in 5000 years !
Flares and origin of life • Kepler has seen 365 superflares (1033-1036 erg) on 148 sun-like stars. • 1035 erg superflares (1000 x the largest solar flare) occur once in 5000 years in our Sun (Maehara et al. 2012). • Superflares cause strong ozone depletion and disaster for the civilization. 1037 erg superflare may cause extinction. • Light-weight M-stars are very common. Their habitable zone is located much closer to the central star. M-stars produce flares with rate 100 x more than sun-like Stars. Superflares on M-type stars fatally radiate the surface of orbiting habitable planets.
Summary • Increase and decrease of sunspots affect Earth’s climate. • The Sun’s current state indicates an upcoming Maunder minimum in 20 years, resulting in global cooling of the Earth. • An ultra-rare super flare could affect our civilization and life on Earth. • Planets with a magnetosphere are in a better position to harbor life.
End

More Related Content

The Sun and Life on Planets by Saku Tsuneta

  • 1. The Sun and Life on Planets Hinode X-ray Sun in 2007 Saku Tsuneta Institute of Space and Astronautical Science (ISAS) Japan Aerospace Exploration Agency (JAXA) 2016 September 5 “Science of the Cosmos, Science in the Cosmos” BBVA Foundation, Madrid
  • 2. Today’s talk • Sunspots and magnetic fields of our Sun • Is the Sun about to run out of sunspots? • Global warming or cooling? • Planetary magnetic fields: a protector for life • Super flares: hazards for life and civilization • Could a second Earth harbor life?
  • 4. EUV Imaging Spectrometer（EIS） Observe plasma temperature & motion Solar Optical Telescope（SOT） High spatial-resolution magnetic field observations X-ray Telescope （XRT） 1-10MK X-ray corona How… … is the magnetic field created? … is the corona heated? … do explosions (solar flares) occur? … is the supersonic solar wind accelerated? 3 well-coordinated advanced telescopes. Orbit: Polar Sun Synchronous JAXA-NASA-UK-ESA Hinode
  • 5. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 6. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 7. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 8. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 9. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 10. Closer and closer to the sun, you begin to see granulation (convection cell)
  • 12. Sunspots have strong magnetic fields Magnetic field line X-ray image of the Sun
  • 13. How strong is the magnetic field of a sunspot? • Sunspot magnetic field is 1000-3000 Gauss. Magnetic field inside the Sun is about 100,000 Gauss! North pole South pole Earth: 0.5 Gauss Milky Way: 0.000001 (one millionth) Gauss Bar magnet：2500 Gauss magnetic wall plaster：800 Gauss
  • 14. Rotation of the Sun Convection inside the Sun Origin of Magnetic fields Kinetic Energy Magnetic Energy Dynamo Coronal heating Solar flares reconnection waves
  • 16. Photosphere and dynamic chromosphere Quiet Photosphere (430nm) Active Chromosphere (396nm) Sunspot
  • 17. Different outlook: Corona seen in X-rays（1-10MK）
  • 18. Prominence sustained by magnetic fields
  • 19. First observation of solar polar region by Hinode
  • 20. How can we see the polar region? • Sun’s axis is tilted 7degree from the Earth’s orbital plane • In March, we can glimpse the Solar South pole. September is a good season to observe North pole. 7 degree Earth location in September Earth location in March Orbital plane of the Earth Rotation axis Observing region in September Observing Region in March
  • 21. Reversal of polar field every 11 years Year 1997 Year 2008 Magnetic map (ESA SOHO) White/blue：plus polarity Black/orange : minus polarity + -+ -
  • 22. Magnetic field around the Sun’s poles Sep. 2012 Sep. 2013 Sep. 2014 Sep.2015 Mar. 2013 Mar. 2014 Mar. 2015 Mar.2016 North Polar Region South Polar Region
  • 23. Year 2008 Year 2012-13 At maximum sunspots, the polar fields were thought to flip together. But, Hinode found that the North pole reversed first, producing a quadrapole. South PLUS South PLUS North PLUSNorth MINUS
  • 25. Persistent and continuous observations of sunspots for 400 years Galileo Galilei (1612) National Astronomical Observatory of Japan (NAOJ, Tokyo, 1998) NAOJ, solar observatory 400 years of continuous observations
  • 26. Few sunspot between 1645～1715 Solar dynamo stopped? Frozen Thames Number of sunspots increases & decreases on 11 year cycle. Drastic decrease in sunspots observed between 1645-1715. Cold period coincides with the Maunder minimum Maunder minimum Dalton minimum Calendar year Sunspotnumber
  • 27. NAOJ, Solar Observatory Unusually long solar-cycle period Launch of Hinode Red line Current cycle Black lines：past 6 cycles overlaid, starting at the minimum.
  • 28. Unusually long solar-cycle period Cycle length 12.6 year! Nominal cycle length 11 year NAOJ, Solar Observatory
  • 30. Similar long period found 200 years ago Calendar year Sunspotnumber
  • 31. How do we observe sunspots on the ancient Sun? Higher solar activity ⇒ Decreases cosmic rays entering Earth’s atmosphere ⇒ Decrease in carbon-14 ⇒ Decrease recorded in tree rings Earth Heliosphere (magnetic fields) Cosmic rays (a) Sun’s magnetic field hinders cosmic rays entering the solar heliosphere Nitride nucleus (b) Cosmic rays bombard Earth’s atmosphere to generate Carbon-14 Carbon cycle Carbon dioxide（14CO2 ） Recorded in tree ring via photosynthesis proton Atmospheric atoms carbon14 Neutron Carbon-14 6 protons and 8 neutrons
  • 32. Blue dots: Miyahara et al., 2004, 2006, 2007, 2008 Red dots: Damon, 2003 Black curve (decadal): Stuiver et al., 1998 (Decadal) MaunderSpoerer Wolf Dalton Oort ~9yr 11~13yr 10~11yr 9~11yr 13~14yr ~14yr ~13yr D14C(permil) ~11yr -30 -10 10 30 800 1100 1400 1700 2000 Year AD Higher solar activity Lower solar activity Lower solar activity is accompanied by longer cycle time and vice versa
  • 33. How do we predict future solar activity?
  • 34. Dynamo process inside the Sun (current paradigm) Polar magnetic fields are the source of sunspot magnetic fields. Indicate future solar activity. Faster equatorial rotation (differential rotation) N S Magnetic field line* N S N S Emerged fields seen as sunspot pair *Magnetic fields behave like rubber tube Amplified Magnetic fields
  • 35. Rapid weakening of solar magnetic field North Pole South Pole Wilcox Solar Observatory Royal Observatory of Belgium Polar Magnetic Field Sunspot Number Year Year Cause Effect Magnetic field polarities flip during the solar maxima periods
  • 36. Cycle period～14yr Cycle period～13yr Cycle period～13yr Is the Sun entering a stagnant period? Asymmetric polarity Sunspot only in south pole (asymmetric polarity)
  • 37. now 11400 years ago 4000 years ago Sunspot number upto 11400 years ago The latest grand maximum started in mid-20 century and ended with the start of new century.
  • 38. From NASA D. Hatraway http://solarscience.msfc.nasa.gov/predict.shtml 2016 July 2030 Cycle 25 2025-26? SSN=50? 2040 Prediction of future sunspot number Cycle 24 (SSN=113 in 2014) the lowest since Cycle14 in 1905 (SSN=105)
  • 39. Does sunspot number affect the Earth?
  • 40. British Met Office announcement February 2015 In the last 15 years, global surface warming has slowed, despite increases in greenhouse gas emissions. (http://www.metoffice.gov.uk/research/news/2015/vari ations-rate-global-warming)
  • 41. The cherry tree historical climate monitor • Temperature determines when cherry trees flower; hotter weather leads to earlier flowering, and vice versa. • Using 822 years of historical records on cherry-blossom viewing parties etc, the past 1200 years of temperatures in Kyoto in March were reconstructed. • Data taken between 1911 – 1940 was used to calibrate, confirming prediction accuracy of 0.1°C. Aono (2012)
  • 42. Conversion of Japanese lunar calendar to modern Gregorian calendar Kyoto: capital of Japan from 794 to 1868 In diaries, chronicles, poems on flowering, viewing parties, events such as gifts to the Emperor are depicted by Emperors, aristocrats, politicians, monks, and merchants. 平 松 時 庸 記 寛 永 廿 一 年 三 月 八 日 （西 暦 一 六 四 四 年 四 月 十 四 日 ） Obtain full-flowering dates of cherry tree (Prunus jamasakura) Prof. Y. Aono, Osaka Prefecture University 於 清 涼 殿 花 御 覧 天 盃 頂 戴
  • 43. Low temperature periods coincide in lower solar activity period Temperature decreases occur close to end of solar minimum. (delay in a few tens of years) Reconstructed temperature and solar activity 10th century warmer than now Aono (2012) Marchmean temperature Full-flowering dates(DOY) Reconstructed Sunspotnumber after removing heat island effect Averaged reconstructed temperature red: 95% confidence level
  • 45. -4000 -3000 -2000 -1000 0 1000 2000 0 20 40 60 Sunspotnumber Years -BC/AD Sunspot number (Usoskin et al., 2007) and cold/wet conditions in Europe (Versteegh, 2005) over 6500 years: 14 cold spells vs 15 Grand minima  12 coincide. Courtesy of Ilya G. Usoskin Cold spells vs. Grand solar minima
  • 46. ⇐1degree C drop ⇐2 degree C drop Temperature decrease during Maunder minimum in Kyoto What would happen if we enter a Maunder minimum?
  • 47. How do planetary magnetic fields protect life and civilization?
  • 48. Sun 48 Shock waves and coronal mass ejection from the Sun propagate toward the Earth in solar wind stream Earth Earth
  • 49. Negative effect of disturbance Quebec blackout (1989)Aurora Satellites and GPS malfunction, radiation hazard
  • 50. Magnetic fields of planets Earth Saturn Jupiter Venus Mars Mercury Direct interaction between Planetary atmosphere and solar wind Formation of strong protective magnetosphere weak strong Photos©NASA
  • 51. Magnetic fields of planets Earth Saturn Jupiter Venus Mars Mercury Direct interaction between Planetary atmosphere and solar wind Formation of strong protective magnetosphere weak strong Photos©NASA ×1/100 ×1 ×600 ×20,000 No magnetic field Small fossil magnetic field
  • 52. Planets and magnetic fields Jupiter Mars Earth VenusMercury Saturn Uranus Neptune
  • 53. Stripping away ancient Martian atmosphere due to intense solar storm • Weak gravity struggles to hold the Martian atmosphere. • Mars lost its own magnetic fields in ancient times. • Young Sun emits intense UV and X-rays. • Initial rich Martian atmosphere may be lost due to intense solar storms.
  • 54. Earth fortunately has a magnetic field…
  • 55. Mars does not have any magnetic field… Mars
  • 56. Humans outside our magnetic field • The Apollo moon missions travelled beyond the Earth’s magnetosphere. • Apollo astronauts showed a greater risk of cardiovascular disease (CVD). • CVD mortality among Apollo astronauts was almost 5 x that of non-flight or ‘low Earth orbit’ astronauts. • The Earth’s magnetosphere protects humans! Delp, M. D. et al. Apollo Lunar Astronauts Show Higher Cardiovascular Disease Mortality: Possible Deep Space Radiation Effects on the Vascular Endothelium. Sci. Rep. 6, 29901 (2016).
  • 58.  なぜ第2の地球を探す？  系外惑星発見前夜  太陽系は標準でない？  すばるにおける惑星探し  ハビタブル惑星とは？  宇宙における生命• 100 billion stars in one galaxy • 100 billion galaxies in universe • In total, 10000000000000000000000000 stars! Big Questions in space science 1. How did life emerge on Earth? 2. Does a second Earth exist? 3. Do extra-terrestrial life-forms exist? 4. What is dark matter and dark energy? 5. How did this universe begin and form?
  • 61. Fraction of stars with at least one planet (period < 85 days) Small 17% 21% 20% 2% 2% Total=62%
  • 63. ３ 将来の展望  If the following materials in the atmosphere are detected, life may exist.  Water  Ozone(oxygen)  Carbon dioxide  Methane  NASA WFIRST・ESA-JAXA SPICA missions are expected to detect these! Spectra of planetary atmosphere Wavelength(micron)Temperature(K) Venus Gelileo （Sagan1993） Can species on other planets guess we are here? Water Ozone Carbon dioxide Earth Mars
  • 64. How do super flares affect life and civilization on Earth and other planets?
  • 65. Occurrence rate of big solar flares (GOES classification in terms of X-ray intensity) Number of Solar Flares year X M C • ---------------- • 1989 59 620 1929 • 1990 16 273 2262 • 1991 54 590 2653 • 1992 10 202 1922 • 1993 0 74 1142 • 1994 0 25 336 • 1995 0 11 148 • 1996 1 4 81 • 1997 3 21 286 • 1998 14 94 1188 • 1999 4 170 1854 • 2000 17 215 2223 • 2001 21 310 2101 C-class flares 1000 events per year M-class flare 100 events per year X-class flare 10 events per year X10-class flare 1 event per year Ｘ100-class flare every 10 years X100000-class flare every 10000 year Every 10 times increase, Occurrence rate one 10th X-class solar flare Soft X-ray intensity
  • 66. Largest flare ever observed: Carrington flare(1859, Sep 1, am 11:18 ） • Richard Carrington in 1859: first record of flare observation • Very bright aurora appeared next day in Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii. • Total energy: 1032erg • Estimated to be the largest magnetic storm (> 1000 nT) in modern history • Telegraph systems all over Europe and North America failed. • Telegraph pylons threw sparks and telegraph paper spontaneously caught fire（Loomis 1861） • The solar storm (flare) on 2012 July 23 observed by STEREO is supposed to be a super- Carrington class, though it occurred on the invisible side of the Sun from the Earth • If it hit the Earth, the estimated economic impact is estimated to be >$2 trillion
  • 67. A super flare recorded in Japanese cedar trees 1035erg super flare? （1000 times larger than the largest flare ever observed） (Miyake et al. Nature , 2012, June, 486, 240) Nature
  • 68. Superflare 10000 times larger than the largest solar flare Maehara et al. (2012) Super flare: Total energy~1036 erg 10000 times larger than the largest solar flares Maehara et al. (2012) Sun Super flares Intensity(visiblelight) Day A star with a big star spot generates super flares
  • 69. Superflare C M X X10 X1000 X100000 Shibataetal.2013 1000 in 1 year 100 in 1 year 10 in 1 year 1 in 1 year 1 in 10 year 1 in 100 year 1 in 1000 year 1 in 10000 year Comparison between solar flares and superflares Largest solar flare Superflares 1000 times more energetic than the largest solar flares occur once in 5000 years !
  • 70. Flares and origin of life • Kepler has seen 365 superflares (1033-1036 erg) on 148 sun-like stars. • 1035 erg superflares (1000 x the largest solar flare) occur once in 5000 years in our Sun (Maehara et al. 2012). • Superflares cause strong ozone depletion and disaster for the civilization. 1037 erg superflare may cause extinction. • Light-weight M-stars are very common. Their habitable zone is located much closer to the central star. M-stars produce flares with rate 100 x more than sun-like Stars. Superflares on M-type stars fatally radiate the surface of orbiting habitable planets.
  • 71. Summary • Increase and decrease of sunspots affect Earth’s climate. • The Sun’s current state indicates an upcoming Maunder minimum in 20 years, resulting in global cooling of the Earth. • An ultra-rare super flare could affect our civilization and life on Earth. • Planets with a magnetosphere are in a better position to harbor life.
  • 72. End