Emergence of life in an inflationary universe.

Abiotic emergence of ordered information stored in the form of RNA is an important unresolved problem concerning the origin of life. A polymer longer than 40-100 nucleotides is necessary to expect a self-replicating activity, but the formation of such a long polymer having a correct nucleotide sequence by random reactions seems statistically unlikely. However, our universe, created by a single inflation event, likely includes more than 10 Sun-like stars.

Lethal Radiation from Nearby Supernovae Helps Explain the Small Cosmological Constant.

The observed value Λ of the cosmological constant Λ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when Λ ≫ Λ. However, the contemporary galaxy formation theory predicts that stars form even with a high value of Λ/Λ ∼ 50, which makes the anthropic argument less persuasive. Here we calculate the probability distribution of Λ using a model of cosmological galaxy formation, considering extinction of observers caused by radiation from nearby supernovae.

Solving the cooling flow problem of galaxy clusters by dark matter neutralino annihilation.

Recent x-ray observations revealed that strong cooling flow of intracluster gas is not present in galaxy clusters, even though it is predicted theoretically if there is no additional heating source. I show that relativistic particles produced by dark matter neutralino annihilation in cluster cores provide a sufficient heating source to suppress the cooling flow, under reasonable astrophysical circumstances including adiabatic growth of central density profile, with appropriate particle physics parameters for dark matter neutralinos. In contrast to other astrophysical heat sources, such as active galactic nuclei, this process is a steady and stable feedback over cosmological time scales after turned on.