Cosmic Rays and Evolution of the Biosphere © 2014 Leonty I. Miroshnichenko N.V. Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), Russian Academy of Sciences (RAS) Colloquium “Space factors of evolution of the biosphere and geosphere”, SAI-MSU, May 2014 D.V. Skobeltsyn Institute of Nuclear Physics (SINP), M.V. Lomonosov Moscow State University (MSU), Moscow

Prerequisites/Motivations/Goals The Earth’s biosphere was born and has developed with permanent ecological factor, namely, with an ever present background of ionizing radiations. The latter are, first of all, natural radioactivity and cosmic rays of galactic and solar origin (GCR and SCR). Above the Earth’s land surface at middle latitudes the radiation background for 2/3 of magnitude is provided by radioactive substances and for 1/3 - it is due to cosmic rays (CR). Above the ocean surface the radiation background is near completely formed by cosmic rays. It may be stated that even now the biosphere still continues its evolution under changing radiation conditions due to variation of background CR intensity. Cosmic rays as one of permanent ecological and biotropical factors. Goals: Summary/review/revision/analysis of relevant astrophysical, geochemical, paleonthological and biological data at modern level of our understanding.

Arising matters: What is the most important? Habitat (environment): Current terrestrial cosmo-biological situation (gravity, radiation, solar activity, geomagnetic field etc.)? Paradox of the “faint early Sun” – observed discrepancy between paleoclimate data and astrophysical models of the Sun’s evolution. astrophysical Variability of solar activity and occurrence rate of solar flares in the epoch of “young Sun”? Inversions of geomagnetic field in the past? Cosmic rays and meteorites in the remote past? Occurrence probability of giant solar flares? Occurrence rate of SN bursts + Contribution of dwarf stars? To estimate the true CR fluxes coming to the Earth.

Let us consider: Cosmic rays and meteorites in the remote past Occurrence probability of giant solar flares Occurrence rate of SN bursts Contribution of dwarf stars (Pamela data) Astrobiology, cosmic rays and Martian experiments

Time scale День (сутки)10 5 с Длительность жизни человека10 9 с (~100 лет) Возраст цивилизации10 4 лет Длительность существования человека10 6 лет Последняя инверсия геомагнитного поля7.8×10 5 лет Возраст галактических космических лучей (ГКЛ)≤10 8 лет Длительность существования млекопитающих10 8 лет Кембрийский взрыв5.4×10 8 лет Длительность существования многоклеточных организмов( )×10 9 лет Длительность существования биосферы (возникновение одноклеточных водорослей) ( )×10 9 лет Возраст Земли(4.54±1%)×10 9 лет Если возраст Земли (4,54 млрд лет ± 1 %) ) принять за сутки, то жизнь на Земле существует всего 17.5 часа, млекопитающие – 30 минут, а человек – только последние 18 секунд. Кембрийский взрыв по этой шкале случился 2.7 часа назад, а возраст ГКЛ, регистрируемых у Земли в настоящее время, не превышает 30 мин.

GCR and Meteorites Isotopes in meteorites: К-40, Т(1/2) = 1.3 Billion years. Cl-36, Т(1/2) = 3.08×10^5 years. A.K. Lavrukhina, 1969; A.K. Lavrukhina, G.K. Ustinova, (V.I. Vernadsky Geochemistry Institute, RAS Moscow). Between ~ Myr ago a summary flux of GCR in the Solar system was ~1/3 of modern level. Relative GCR variations in the past by long-lived products of nuclear reactions in meteorites due to CR bombardment: F(t) – CR flux at remote time t, F(0) – modern level (data for 11 iron meteorites). Cambrian Period, MYA (Million Years Ago)…

Past Galactic arm crossings A compilation of 74 iron meteorites which were K(41)/K(40) exposure dated (Voshage & Feldman, 1979). To avoid real clustering in the data (due to one parent body generating many meteorites) N.J. Shaviv has removed all occurrences of Fe meteorites of the same classification that are separated by less than 100 Myr and replace them by the average. This left him with 42 meteorites. (Nir J. Shaviv, 2002).

Biotic extinctions and giant solar flares The occurrence rate of giant flares can be also estimated from some circumstantial data. For example, it is suggested (Beland and Russel, 1976) that the recently discovered 4 cases of extinction of Radiolaria for the last 2.5 My were due to the occurrence of such giant flares with a frequency ~ 10^(-4)/year coinciding with the geomagnetic inversion period. Extrapolating their highest energies (>60 MeV) fit to long time scales, Kiraly and Wolfendale (1999) obtained some new interesting estimates. It turns out that while the highest fluence measured up to now (in about 30 years) was 3  10^9 cm^(-2), one would expect in 1 My a few events above 10^12 cm^(-2), and in 100 My a few above 10^13 cm^(-2). This is far less than one would expect from flat slopes found by Wdowczyk and Wolfendale (1977), but probably more realistic. Thus, the largest solar particle events in geological history should have been not more than 10^3 to 10^4 times larger than those detected so far, giving rise to only moderate “energetic particle catastrophes”. Those estimates, however, seem to be overestimated: see below our estimates for the fluences of Φ(≥30 MeV).

SN bursts and biotic extinctions Relative occurrence rate of Supernova bursts (solid curve) in comparison with a number of marine animal genera becoming extinct during any given time interval. animalgenera According to Svensmark (2012), the Galaxy let the reptiles down. However, the author’s correction for the ocean level changes rather significantly the original set of data and should be undergo to additional verification.

Variations of the concentration of the oxygen isotope 18O (Veizer et al., 1999). Terrestrial Climate in the Phanerozoic Eon On the other hand, there are independent climatic data (Veizer et al., 1999) that points to the variations of the concentration of the oxygen isotope 18O (as one of the best climatic index) at large time scale. All maximums obtained by Veizer et al. (1999) coincide with the Svensmark’s curve.

The true CR fluxes near the Earth? It has been pointed out that there is no record of solar superflares over the past 2,000 yr. According to the measurement of the impulsive nitrate events in polar ice, the largest proton flare event during the past 450 yrs is the Carrington event, which occurred on 1 September The total energy released in this flare was estimated to be of order 10^32 erg, which is only 1/1,000 of the maximum energy of flares on slowly rotating Sun- like stars. Maehara H. et al. Superflares on solar-type stars. Nature 24 May 2012, v. 485, 479 – 481. Flare activity of the Sun is less of ~ (3 - 4) order of magnitude than that of the most active dwarf stars. The latter may serve as cosmic ray sources up to the energies of eV. Life time of CR is ~ 10^7 y.

PAMELA Results: New Challenge? Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. Adriani et al. (2011) reported precision measurements of the proton and helium spectra in the rigidity range from 1 GV to 1.2 TV performed by the satellite- borne experiment PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics). It was found that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in Supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in PAMELA data (Adriani et al. Science. 2011, Apr 1; 332(6025): E-pub. 2011, March 3).Science. Stozhkov’s hypothesis: In our Galaxy, side by side the Supernovas, there are other sources of CR in the PAMELA energy range. The main candidates of this kind are so-called dwarf stars.

Proton (left) and helium (right) spectra measured in the range 10 GV-1.2 TV

Cosmic rays near the Earth’s orbit from SN bursts and solar flares Integral occurrence rate of SCR events at given energy density at the Earth’s orbit (top plots). Estimates of ionization contribution from SN gamma-flash (bottom plots) at the distance of 10 parsec from the Earth (flash) and from protons for the periods of Earth’s stay in SN remnant during 3 years (3 yr) and during all the time (all time). Wdowczyk and Wolfendale, Ionization effects from energetic particles (GCR and SCR) and electromagnetic emissions (X- and gamma rays from SNe).

Distribution function of SEP events Recently, some progress in the specification of the distribution function of SEP events in the range of Low Probabilities was achieved due to new results of the study of Greenland Ice Cores (GIC). Important (unique) data on the fluences of large SEP events in the past were obtained for the period of (McCracken et al., 2001; Townsend, 2003). In particular, it was estimated a fluence of protons of ≥30 MeV for the largest SEP event of that period registered on 1-2 September 1859 (Carrington event). Φ(≥30 MeV) = 1.88×10^10 protons/cm^2.

Solar Extreme Event of 1859 Integral energy spectrum of peak (maximum) fluxes of protons for the Carrington event of 1-2 September 1859 (solid blue line with stars), together with r.m.s. deviations (dashed blue lines). Red line - Upper Limit Spectrum (ULS) for Solar Cosmic Rays (SCR) by Miroshnichenko (1994, 1996); green triangles - ULS corrected by Miroshnichenko & Nymmik (Radiation Measurements, 2014).

SEP Fluences (≥30 MeV) Синим цветом показаны Гренландские данные, начиная с 1561 г. Well-known time markers due to the eruptions of two volcanoes - Sheveluch in 1854 and Chikurachki- Tatarinov in provide good definition of the absolute timescale (McCracken et al., JGR, 2001).

GCR + SCR bombard Mars Detection of the organic matter on Mars is one of the main goals of the current and future Martian landing missions. However, as noted by Pavlov et al. (2012), the degradation of organic molecules by cosmic ray irradiation on Mars is often ignored. The authors calculated the accumulation rates of radiation dose from solar and galactic cosmic rays at various depths in the shallow Martian subsurface. It was shown that a 1 Gyr outcrop on Mars accumulates the dosage of ~500 MGy (MegaGrey) in the top 0÷2 cm and ~50 MGy at 5÷10 cm depths. It means that the preservation of ancient complex organic molecules in the shallow (~10 cm depth) subsurface of rocks could be highly problematic if the exposure age of a geologic outcrop would exceed 300 Myr. On the other hand, it was demonstrated that more simple organic molecules with masses ~100 amu should have a good chance to survive in the shallow subsurface of rocks. P.S. Martian magnetic field is ~ 1/500 of terrestrial one?

Astrobiology, cosmic rays and Martian experiments Exposure time (a) at 1 cm and (b) at 5 cm depths necessary for a 1000-fold decrease in the organic molecules abundance vs. molecular mass of the organic compounds. The “standard” Martian surface rock composition and 7 mbar atmosphere were assumed for calculations of GCR contribution. Calculations of the organic degradation due to SCR assume that the atmospheric pressure drops to 0.2 mb for 10% of Martian history in the last billion years (for more details see Pavlov et al., 2012).

The GHZ in the disk of the Milky Way based on the star formation rate, metallicity (blue), sufficient time for evolution (gray), and freedom from life- extinguishing supernova explosions (red). The white contours encompass 68% (inner) and 95% (outer) of the origins of stars with the highest potential to be harboring complex life today. The green line on the right is the age distribution of complex life and is obtained by integrating P(r, t) over r. Here P(GHZ) is a probability to survive… Charles H. Lineweaver, Yeshe Fenner, Brad K. Gibson. The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way. (Science, Jan 2, 2004). Probability to survive…

Evolution-Adaptation Syndrome? Modern response of biological systems to cosmophysical factors ( solar-terrestrial disturbances) may be considered as an ancient “atavistic reaction” on the changes of habitat conditions, i.e. as an Evolution-Adaptation Syndrome (EAS). This concept enables to change in wide range the energies, forms and mechanisms of effective external influence in the development of theoretical models of the biosphere evolution in the remote past (e.g., in the epoch of «young Sun»).

“We will never meet them…” A new paper by Falguni Suthar and Christopher McKay (NASA Ames) “The Galactic Habitable Zone in Elliptical Galaxies,” International Journal of Astrobiology (published online 16 February 2012). One of the comments (Henk): “We will never meet one of those beings, may be it is better that we will never meet them. We will never fight war against them. I think that inteligent life is very rare, but not as rare that we are alone…” Thank you…

References 1. Л.И. Мирошниченко. Физика Солнца и солнечно-земных связей. - Москва, НИИЯФ МГУ: Университетская книга, 2011, 174 с., lib.qserty.ru/static/tutorials/133_Miroshnichenko_2011.pdf 2. В.Н. Обридко, Л.И. Мирошниченко, М.В. Рагульская, О.В. Хабарова, E.Г. Храмова, М.М. Кацова, М.А. Лившиц. Космические факторы эволюции биосферы: Новые направления исследований. - Проблемы эволюции биосферы. - Серия «Гео-биологические системы в прошлом». Москва, Палеонтологический Институт РАН, 2013, c.66–94, 3. L.I. Miroshnichenko. Cosmic Rays and Evolution of the Biosphere: Search for New Approaches. – Proc. Int. Conference “Space Weather Effects on Humans in Space and on Earth”. 2013, v.1, p L.I. Miroshnichenko, R.A. Nymmik. Extreme fluxes in solar energetic particle events: Methodological and physical limitations. - Radiation Measurements, 2014, v.61, p Л.И. Мирошниченко, О.В. Хабарова. Космофизическая ситуация в эпоху Кембрийского эволюционного взрыва. - Серия «Гео- биологические системы». Труды конференции «Становление скелета у различных групп организмов и биоминерализация в истории Земли». Москва, Палеонтологический Институт РАН, 2014 (в печати).

Acknowledgements NOT… THE END?... This work is partially supported by RAS_28 Program of Fundamental Research “Problems of the life origin and formation of the biosphere” (Russian Academy of Sciences). The Sector for Helio-Ecological Connections - NEW IZMIRAN web-site in RUSSIAN: