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Some microbes appear to be able to metabolize in glacial ice or permafrost. The rate depends on temperature, nutrient level, and bioelement availability, among other factors. I have developed a plausible argument that they do this while…

种群与进化 · 定量生物学 2007-05-23 P. Buford Price

Massive cores of the giant planets are thought to have formed in a gas disk by accretion of pebble-size particles whose accretional cross-section is enhanced by aerodynamic gas drag [1][2]. A commonly held view is that the terrestrial…

地球与行星天体物理 · 物理学 2021-09-24 M. Brož , O. Chrenko , D. Nesvorný , N. Dauphas

Understanding the origin of comets requires knowledge of how the Solar System formed from a cloud of dust and gas 4.567 Gyr ago. Here, a review is presented of how the remnants of this formation process, meteorites and to a lesser extent…

地球与行星天体物理 · 物理学 2025-06-04 Bernard Marty , Katherine R. Bermingham , Larry R. Nittler , Sean N. Raymond

Planetesimal formation stage represents a major gap in our understanding of the planet formation process. The late-stage planet accretion models typically make arbitrary assumptions about planetesimals and pebbles distribution while the…

地球与行星天体物理 · 物理学 2017-12-13 Joanna Drazkowska , Yann Alibert

Interstellar formamide (NH2CHO) has recently attracted significant attention due to its potential role as a molecular building block in the formation of precursor biomolecules relevant for the origin of life. Its formation, whether on the…

The formation of planetesimals is often accredited to collisional sticking of dust grains. The exact process is unknown, as collisions between larger aggregates tend to lead to fragmentation or bouncing rather than sticking. Recent…

地球与行星天体物理 · 物理学 2015-06-03 Fredrik Windmark , Til Birnstiel , Carsten Güttler , Jürgen Blum , Cornelis P. Dullemond , Thomas Henning

To study the terrestrial-type planet formation during the post oligarchic growth, the initial distributions of planetary embryos and planetesimals used in N-body simulations play an important role. Most of these studies typically use ad hoc…

地球与行星天体物理 · 物理学 2015-11-18 M. P. Ronco , G. C. de Elía , O. M. Guilera

Global models of planet formation tend to begin with an initial set of planetary embryos for the sake simplicity. While this approach gives valuable insights on the evolution of the initial embryos, the initial distribution itself is a bold…

地球与行星天体物理 · 物理学 2022-10-26 Oliver Voelkel , Hubert Klahr , Christoph Mordasini , Alexandre Emsenhuber

Volatile compositions of asteroids provide information on the Solar System history and the origins of Earth's volatiles. Visible to near-infrared observations at wavelengths of $<2.5\ {\rm \mu m}$ have suggested a genetic link between outer…

地球与行星天体物理 · 物理学 2021-12-21 H. Kurokawa , T. Shibuya , Y. Sekine , B. L. Ehlmann , F. Usui , S. Kikuchi , M. Yoda

Our understanding of the process of terrestrial planet formation has grown markedly over the past 20 years, yet key questions remain. This review begins by first addressing the critical, earliest stage of dust coagulation and concentration.…

地球与行星天体物理 · 物理学 2024-11-07 Matthew S. Clement , Andre Izidoro , Sean N. Raymond , Rogerio Deienno

The origin of life and the origin of the universe are among the most important problems of science and they might be inextricably linked. Hydro-gravitational-dynamics (HGD) cosmology predicts hydrogen-helium gas planets in clumps as the…

宇宙学与河外天体物理 · 物理学 2015-05-18 Carl H. Gibson , Rudolph E. Schild , N. C. Wickramasinghe

Pebbles of millimeter sizes are abundant in protoplanetary discs around young stars. Chondrules inside primitive meteorites - formed by melting of dust aggregate pebbles or in impacts between planetesimals - have similar sizes. The role of…

地球与行星天体物理 · 物理学 2021-02-18 Anders Johansen , Thomas Ronnet , Martin Bizzarro , Martin Schiller , Michiel Lambrechts , Åke Nordlund , Helmut Lammer

It is often presumed, that life evolves relatively fast on planets with clement conditions, at least in its basic forms, and that extended periods of habitability are subsequently needed for the evolution of higher life forms. Many planets…

地球与行星天体物理 · 物理学 2017-11-23 Claudius Gros

Life appears to have emerged relatively quickly on the Earth, a fact sometimes used to justify a high rate of spontaneous abiogenesis ($\lambda$) among Earth-like worlds. Conditioned upon a single datum - the time of earliest evidence for…

地球与行星天体物理 · 物理学 2018-12-26 Jingjing Chen , David Kipping

About 4 billion years ago, the Earth probably fulfilled the environmental conditions necessary to favour the transition from primitive chemistry to life. Based on a theoretical hairpin duplication origin of tRNAs and their putative…

生物物理 · 物理学 2025-01-27 Juan Jimenez

A high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the terrestrial planets region contain nearly none. We study the fate of the…

地球与行星天体物理 · 物理学 2017-10-04 Hans-Peter Gail , Mario Trieloff

Giant planet embryos are believed to be spawned by gravitational instability in massive extended (R ~ 100 AU) protostellar discs. In a recent paper we have shown that dust can sediment inside the embryos, as argued earlier by Boss (1998) in…

地球与行星天体物理 · 物理学 2015-05-19 Sergei Nayakshin

Pebble accretion provides new insights into Earth's building blocks and early protoplanetary disk conditions. Here, we show that mixtures of chondritic components: metal grains, chondrules, calcium-aluminum-rich inclusions (CAIs), and…

地球与行星天体物理 · 物理学 2025-07-23 Susmita Garai , Peter L. Olson , Zachary D. Sharp

The porosity of an asteroid is important when studying the evolution of our solar system through small bodies and for planning mitigation strategies to avoid disasters due to asteroid impacts. Our knowledge of asteroid porosity largely…

地球与行星天体物理 · 物理学 2021-03-02 Tomomi Omura , Akiko M. Nakamura

We propose an expression for a local planetesimal formation rate proportional to the instantaneous radial pebble flux. The result --- a radial planetesimal distribution --- can be used as initial condition to study the formation of…

地球与行星天体物理 · 物理学 2019-04-09 Christian T. Lenz , Hubert Klahr , Tilman Birnstiel