scholarly journals Possible Transfer of Life by Earth-Grazing Objects to Exoplanetary Systems

Life ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 44
Author(s):  
Amir Siraj ◽  
Abraham Loeb
Keyword(s):  
Solar System ◽  
Binary Star ◽  
Earth’S Atmosphere ◽  
Exoplanetary Systems ◽  
Earth's Atmosphere

Recently, a 30-cm object was discovered to graze the Earth’s atmosphere and shift into a Jupiter-crossing orbit. We use the related survey parameters to calibrate the total number of such objects. The number of objects that could have exported terrestrial microbes out of the Solar System is in the range 2 × 10 9 – 3 × 10 11 . We find that 10 7 – 10 9 such objects could have been captured by binary star systems over the lifetime of the Solar System. Adopting the fiducial assumption that one polyextremophile colony is picked up by each object, the total number of objects carrying living colonies on them upon capture could be 10– 10 3 .

Introduction

1999 ◽  
Author(s):  
Yuk L. Yung ◽  
William B. DeMore
Keyword(s):  
Solar System ◽  
Solar Radiation ◽  
Atmospheric Chemistry ◽  
Past History ◽  
Chemical Change ◽  
Visible Spectrum ◽  
Rate Of Change ◽  
The Sun ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere

It is usual in the study of planets to consider the Earth first, and then the other planets, so that we can better understand how and why the rest of the solar system is different from us. In this book the order of study will be reversed: we shall first try to understand the solar system, and then we will ask why Earth is unique. We adopt this unconventional approach for two reasons. First, Earth's atmosphere today is the end-point of an evolution that started about 4.6 billion years ago. The pristine materials have all been drastically altered. However, by examining other parts of the solar system that have evolved to a lesser degree, we may deduce what the early Earth might have been like. Second, Earth's atmosphere today is largely determined by the complex biosphere, whose evolution has been intimately coupled to that of the atmosphere. In other words, ours is the only atmosphere in the solar system that supports life, and it is in turn modified by life. Therefore, to appreciate the beauty and the intricacy of our planet, we must start with simpler objects without life. Chemical composition is intimately connected to evolution, which in turn is driven by chemical change. In this book we attempt to provide a coherent basis for understanding the planetary atmospheres, to identify the principal chemical cycles that control their present composition and past history. Figure 1.1 gives an illustration of the intellectual framework in which our field of study is embedded. The unifying theme that connects the planets in the solar system is "origin"; that is, all planets share a common origin about 4.6 billion years ago. The subsequent divergence in the solar system may be partly attributed to evolution, driven primarily by solar radiation. The bulk of solar radiation consists of photons in the visible spectrum with a mean blackbody radiation temperature of 5800 K. The part that is responsible for direct atmospheric chemistry is a tiny portion (less than 1% of the total flux) in the ultraviolet. In addition, the sun emits a steady stream of corpuscular particles, known as the solar wind. While the sun provides the principal source of energy for change, the time rate of change is crucial, and that is where chemical kinetics and chemical cycles play pivotal roles.

History of the Earth’s Atmosphere

1987 ◽  
Author(s):  
Michael I. Budyko ◽  
Alexander B. Ronov ◽  
Alexander L. Yanshin
Keyword(s):  
Earth’S Atmosphere ◽  
History Of ◽  
Earth's Atmosphere
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