Dark energy and the anthropic principle

The Hubble constant is split into two terms H = H₁ + H₂ , where H₁ is a decreasing function due to the Big Bang and the subsequent gravitational interaction that slows the expansion of the Universe and H₂ is an increasing function that corresponds to dark energy which accelerates this expansion. For T = 13.7 Gyr we prove that H₂(T) > 5 m/(yr AU). This is a quite large number and thus the impact of dark energy, which is spread almost everywhere uniformly, should be observable not only on large scales, but also in our Solar system. In particular, we show that Earth, Mars and other planets were closer to the Sun 4.5 Gyr ago. The recession speed ≈5.3 m/yr of the Earth from the Sun seems to be just right for an almost constant influx of solar energy from the origin of life on Earth up to the present over which time the Sun’s luminosity has increased approximately linearly. This presents further support for the Anthropic Principle. Namely, the existence of dark energy guarantees very stable conditions for the development of intelligent life on Earth over a period of 3.5 Gyr.     

Heliospheric Observations of STEREO-Directed Coronal Mass Ejections in 2008?–?2010: Lessons for Future Observations of Earth-Directed CMEs

We present a study of coronal mass ejections (CMEs) which impacted one of the STEREO spacecraft between January 2008 and early 2010. We focus our study on 20 CMEs which were observed remotely by the Heliospheric Imagers (HIs) onboard the other STEREO spacecraft up to large heliocentric distances. We compare the predictions of the Fixed-?? and Harmonic Mean (HM) fitting methods, which only differ by the assumed geometry of the CME. It is possible to use these techniques to determine from remote-sensing observations the CME direction of propagation, arrival time and final speed which are compared to in-situ measurements. We find evidence that for large viewing angles, the HM fitting method predicts the CME direction better. However, this may be due to the fact that only wide CMEs can be successfully observed when the CME propagates more than 100^° from the observing spacecraft. Overall eight CMEs, originating from behind the limb as seen by one of the STEREO spacecraft can be tracked and their arrival time at the other STEREO spacecraft can be successfully predicted. This includes CMEs, such as the events on 4 December 2009 and 9 April 2010, which were viewed 130^° away from their direction of propagation. Therefore, we predict that some Earth-directed CMEs will be observed by the HIs until early 2013, when the separation between Earth and one of the STEREO spacecraft will be similar to the separation of the two STEREO spacecraft in 2009??C?2010.     

Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager

We compare line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) and the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO). The line-of-sight magnetic signal inferred from the calibrated MDI data is greater than that derived from the HMI data by a factor of 1.40. This factor varies somewhat with center-to-limb distance. An upper bound to the random noise for the 1′′ resolution HMI 720-second magnetograms is 6.3 Mx?cm^?2, and 10.2 Mx?cm^?2 for the 45-second magnetograms. Virtually no p-mode leakage is seen in the HMI magnetograms, but it is significant in the MDI magnetograms. 12-hour and 24-hour periodicities are detected in strong fields in the HMI magnetograms. The newly calibrated MDI full-disk magnetograms have been corrected for the zero-point offset and underestimation of the flux density. The noise is 26.4 Mx?cm^?2 for the MDI one-minute full-disk magnetograms and 16.2 Mx?cm^?2 for the five-minute full-disk magnetograms observed with four-arcsecond resolution. The variation of the noise over the Sun’s disk found in MDI magnetograms is likely due to the different optical distortions in the left- and right-circular analyzers, which allows the granulation and p-mode to leak in as noise. Saturation sometimes seen in sunspot umbrae in MDI magnetograms is caused by the low intensity and the limitation of the onboard computation. The noise in the HMI and MDI line-of-sight magnetic-field synoptic charts appears to be fairly uniform over the entire map. The noise is 2.3 Mx?cm^?2 for HMI charts and 5.0 Mx?cm^?2 for MDI charts. No evident periodicity is found in the HMI synoptic charts.     

A red giant with a strange star as its core. Principal similarities to and differences from Thorne-Zytkow objects

A model red giant with a mass of 5 M_⊙ a luminosity of 41,740 L_⊙, and a radius of 960 R_⊙ and with a strange quark star as its core is constructed, and it is compared with a Thorne-Zytkow object having similar integrated parameters. The difference in internal structure is manifested right at the dense core: matter above the core is held off only by γ rays from the strange star, and convection is maintained down to the strange star. The lifetime of a red giant containing a strange star turns out to be almost 500 times shorter than that of a Thorne-Zytkow object — on the order of 10⁵ years. Translated from Astrofizika, Vol. 41. No. 4, pp. 533–544, October–December, 1998.