Post by auntym on Feb 12, 2015 15:56:37 GMT -6
www.npr.org/blogs/13.7/2015/02/11/385413799/should-we-be-afraid-of-aliens?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20150211
Should We Be Afraid Of Aliens?
February 11, 2015
Marcelo Gleiser
Might nightmarish alien beings, like these imagined ones, invade Earth?
iStockphoto
In the long list of modern fears, bloodthirsty aliens may not rank near the top. We have more immediate worries, from terrorism and bioengineered (or not) global epidemics to nuclear holocaust and natural disasters.
However, the notion that other intelligences exist out there in the universe is pervasive in popular culture. Mirrors to our own history, in particular colonial exploitations, aliens are often portrayed as evil invaders bent on coming here to wreak havoc.
How realistic are these scenarios, given what we know now about astronomy and the possibility of life in other worlds?
Stephen Hawking, among others, has suggested that we should be very careful with aggressive aliens — that, in fact, we should be as stealthy as possible, lest we reveal our presence and location to predatory ETs in our cosmic neighborhood.
There are three parts to this. The first concerns the existence of other worlds with habitable conditions — that is, that can harbor life as we know it. Thanks to the efforts of the many planet hunters out there, in particular the remarkable results from NASA's Kepler mission, we now know that most stars have planets surrounding them. Thousands of these planets have been identified, and, among these, several have properties similar to Earth: rocky and within the habitable zone of their main star. Although the majority of these orbit small and cooler M dwarf stars, where conditions for life may be very harsh indeed, the fact is that we should expect a few Earth-like worlds within a distance of about 1,000 light years or so.
Whether any of these potentially habitable worlds are, in fact, able to harbor life, is another story. In the next few decades, with combined efforts from the James Webb Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) mission, as well as missions from the European Space Agency, we should know better how rare such Earth-like planets are and, with luck, have a rough idea of their atmospheric composition. We should be able to know if their atmospheres have some of the right ingredients for harboring life. (There are, however, several potential shortcomings with these missions. For a very nice review of the situation, see Lee Billings' recent article for Scientific American.)
CONTINUE READING: www.npr.org/blogs/13.7/2015/02/11/385413799/should-we-be-afraid-of-aliens?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20150211
Should We Be Afraid Of Aliens?
February 11, 2015
Marcelo Gleiser
Might nightmarish alien beings, like these imagined ones, invade Earth?
iStockphoto
In the long list of modern fears, bloodthirsty aliens may not rank near the top. We have more immediate worries, from terrorism and bioengineered (or not) global epidemics to nuclear holocaust and natural disasters.
However, the notion that other intelligences exist out there in the universe is pervasive in popular culture. Mirrors to our own history, in particular colonial exploitations, aliens are often portrayed as evil invaders bent on coming here to wreak havoc.
How realistic are these scenarios, given what we know now about astronomy and the possibility of life in other worlds?
Stephen Hawking, among others, has suggested that we should be very careful with aggressive aliens — that, in fact, we should be as stealthy as possible, lest we reveal our presence and location to predatory ETs in our cosmic neighborhood.
There are three parts to this. The first concerns the existence of other worlds with habitable conditions — that is, that can harbor life as we know it. Thanks to the efforts of the many planet hunters out there, in particular the remarkable results from NASA's Kepler mission, we now know that most stars have planets surrounding them. Thousands of these planets have been identified, and, among these, several have properties similar to Earth: rocky and within the habitable zone of their main star. Although the majority of these orbit small and cooler M dwarf stars, where conditions for life may be very harsh indeed, the fact is that we should expect a few Earth-like worlds within a distance of about 1,000 light years or so.
Whether any of these potentially habitable worlds are, in fact, able to harbor life, is another story. In the next few decades, with combined efforts from the James Webb Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) mission, as well as missions from the European Space Agency, we should know better how rare such Earth-like planets are and, with luck, have a rough idea of their atmospheric composition. We should be able to know if their atmospheres have some of the right ingredients for harboring life. (There are, however, several potential shortcomings with these missions. For a very nice review of the situation, see Lee Billings' recent article for Scientific American.)
CONTINUE READING: www.npr.org/blogs/13.7/2015/02/11/385413799/should-we-be-afraid-of-aliens?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20150211