You may wonder what another civilization might regard as relatively reliable biosignatures of Earth, were this civilization to observe Earth from a distance of tens of light-years.
Science writer Lee Billings accomplishes a lot in the pages of Five Billion Years of Solitude: The Search for Life Among the Stars (published in the U...
The discovery (if and when it happens) of extraterrestrial complex life will undoubtedly usher in a revolution that will rival the Copernican and Darwinian revolutions combined.
Check out the Milky Way next time you're outside the glare of city lights, and ruminate on the thought that at least 33 billion habitable planets are somewhere up there. But that's just the local population.
The holy grail of astrobiology, currently, lies in identifying Earth-sized worlds within the habitable zone of their star and with the possibility of an atmosphere that might support life.
Could it be that our planet isn't typical at all? If so, then maybe life isn't typical either. On the other hand, if there are plenty of planets similar to Earth, we can reasonably hope for lots of cosmic company.
It seems that the frequency of planets able to support life is roughly one percent. In other words, a billion or more such worlds exist in our galaxy alone. That's a lot of acreage, and it takes industrial-strength credulity to believe it's all bleakly barren.
News reports on the discovery of "habitable" planets are highly misleading. What scientists define as habitable just means that conditions may exist that are adequate for life based on carbon chemistry, such as the generic type of life we have on Earth.
Imagine a world where the Sun doesn't shine -- ever. A place where there are nights but no days, and where the term "year" has no meaning. On such an unlit world, you'll never see anything in the sky brighter than the puny sparkle of the stars.
The question become particularly intriguing when we realize that astronomers now estimate that the Milky Way galaxy alone may harbor as many as 4.5 billion Earth-sized planets in the "habitable zones" around their host stars.
The paucity of impact-making announcements by female astronomers in general is dreadful. How can it be, that well over a century after the first women received PhDs in astronomy, women have failed to match their male peers in this and other aspects of STEM academia?
News like this -- that the galaxy is bristling with potential broadcast platforms -- will only embolden these go-go pioneers. Hand them 160 billion planets and what will they say? What they've been saying all along: They just have to be out there -- meaning them.
The last few years have been heady for planet hunters. First the hot Jupiters; then the will-o'-the-wisp Glieslings and their cousins; and the results from the Kepler mission, one of which is Kepler-22b.
After a starquake, says NASA's Dr. Jon Jenkins, "stars actually change their shape. This shape change causes an apparent change in brightness. As we study the brightness variations in time, we can essentially hear the songs of the stars."
Gliese 581 may be small as stars go, but it looms huge in the vision field of planetfinders.
The type of multiple-planet solar system we live in isn't oddball at all, but is as humdrum as hairpins. That would, of course, be good news for those who hope to find extraterrestrial life.