Another planet the size of Earth?
What do we know about it?
What does this mean?
For more use the DOOR.
First, exciting news is often presented in sensational form. One purpose of ADOZENSECONDS.COM is help people understand the fine print. (Often by creating fine print of our own…) Before quoting from the article by Amina Khan that appeared in the 18 April 2014 Orlando Sentinel, let me review a few things we’ve discussed from time to time…and add a piece or two of new information:
• We now have evidence for the existence of about 1800 exoplanets (planets beyond our Solar System). When most of you who are reading this were born, we had evidence for “0” exoplanets. This evidence comes, largely, from the Kepler Space and Hubble Space Telescopes.
• Are these planets like Earth? The overwhelming majority are gaseous balls like, say, Jupiter–with no way of harboring single-celled life, much less complex plant and animal life…or humans.
• Roughly speaking, a planet that could support life must exist in a “Goldilocks zone” (with “just right” conditions). These include a size and composition very, very similar to that of Earth and a similar-sized Sun (similar to ours); just right temperature and radiation exposure; water; the right available chemical composition, including “proper ratios” of chemicals to each other; and dozens of other things…
• Do we have ways of being sure they’re made of stuff that’s similar to what’s in our solar system? Yes. We can analyze the light sent from them. Each element can produce a unique spectrum of light waves, or a “fingerprint” of light bands that prisms in our fancy optical equipment can sort out. The universe, it appears, is made of stuff that can be identified by the familiar Periodic Tables in our old science texts.
• How far away are these exoplanets? Very far. This one is about 500 light-years away. In other words, it takes light reflected from it 500 years to get to us…
Now, part of the article. As always, we encourage close examination of what’s actually said and inferred. And, of course what’s not said.
Earth-size planet found in “habitable zone.”
“Sifting through observations from more than 100,000 distant stars, astronomers say they have discovered the first definitive Earth-size planet that orbits in a habitable zone where water could exist in liquid form–a necessary condition for life as we know it.
“Scientists don’t know if the planet actually has water or a protective atmosphere. They don’t even know its mass. But they said the landmark discovery gives astronomers great hope that a bumper crop of Earth-like planets is waiting to be found much closer to home, including around temperamental stars that until recently were considered inhospitable to life.
” ‘This is really a tip-of-the-iceberg discovery,’ said Jason Rowe, an astronomer at the SETI Institute in Mountain View, Calif., who spent a year analyzing data gathered by NASA’s Kepler Space Telescope and was part of a team that described the planet in Friday’s edition of the journal Science. After finding the planet known as Kepler-186f, ‘we can infer that other ones are likely to exist.’ Locating them will be ‘the job of future missions.’….
“Out of the 1800 or so confirmed planets outside the solar system, fewer than two dozen sit in the habitable zone where it’s not so hot that water would boil off into space and not so cold that it would remain permanently locked in ice.”