Introduction to the handbook of cosmic hazards and planetary defense #1

Abstract

Each year humans travel through space on their own very special spacecraft called planet Earth, but that trip around theSun is actually a very hazardous journey. Without the benefit of a space program, thehuman species has spent millions of years unaware of the wide range of cosmic dangersthat lurk out in space. In some ways humansare playing Russian Roulette with a random set of rock and metal bullets that were firstfired at this small six sextillion tonplanet millions if not billions of years ago. These bullets are potentially hazardousasteroids, bolides, and meteorites. In addition there are comets that streak down toward theSun from the Oort Cloud every few years. Perhaps an even greater danger to humans comefrom the nearby nuclear furnace calledthe Sun. Solar flares, coronal mass ejections, and continuous radiation from the Sun are warded off by the Van Allen Belts, the Earth’s geomagnetosphere, and the ozone layer that sits atop the stratosphere. During the height of the Sun’s activity that follows an 11-year cycle, the radiation and solar eruptions from the Sun hit very dangerous levels. Current research that examinesthe Van Allen Belts and theEarth’s magnetic shielding suggests that the protective magnetosphere shieldingthat protectslife could be changing. And then there are other hazards from space. These risks include increasing levels of orbital debris and returning spacecraft that may contain nuclear, radiological, or chemical dangers, or even biological dangers.The seeks to examine in depth the various dangers that the delicate Earth Habitat could be exposedto from outer space risks and what research needs to be done to understand in greater depth the nature of these dangers. And the editors and the authorsof this book are defining “cosmic hazards”in the broadest possible terms. Thus, thesehazards from outer space include comets, asteroids, and bolides that might collide with Earth. The risks to humans and modern global infrastructure include solar flares, coronal mass ejections, solar proton events, and other space weather events, as well as changes to the Earth’s protective shielding from cosmic hazards such as a lessened magnetosphere, altered Van Allen Belts, and a depleted ozone layer. This chapter also addresses orbital debris (in terms of its impact on Earth and aircraft as well as such debris possibly endangering vital infrastructure and satellite networks). This chapter even considers such hazards ascosmic radiation, antimatter events, and lethal biological agents that could come to Earth in various forms, including via returning spacecraft or astronauts.The last part of the chapter builds on what is known about thedangers of outer space and presents the various types of activities that humans are beginning to undertake to protect life on Earth. This latter part of the handbook sets forth what types of activities can serve to protecthumans and indeed all types of life-forms from mass extinctions. Suchmassiveloss of species that include a third or more of all types of life-forms has been documented to have occurred at least fivetimes during theEarth’s existence. These past mass extinction events have comeabout, on average, every 300 million years orso, overthe last two billion years. These massive losses of life serve as powerfulreminder that not only are therepowerful hazards thatcanwipe out life on a massive scale, but that unless protective measures are undertaken, theycould happen again withdevastatingeffect. The rise of mass urbanization thatmay exceed 70 % of all people livingintowns of cities by 2100 coupledwith theenormous dependence on moderninfrastructuresuch as electric power grids, telecommunications and informationsystems, and vast utilityplants make twenty-first-centuryvulnerabilities to cosmic risks fargreater than any previous time in human history.Theobjective ofthis chapteris thus to present in detail what is known about the hazards of outer space and the scientific and technical natureofthese threats. Further this handbookseeksto identify what steps can be undertakento initiate a creditable planetarydefense effort. It is such an effort that can uniteallthe people of planet Earth in a greatand common undertaking.