Daily Archives: April 15, 2012
Over the past 16 years, astronomers have detected more than 3,035 (2,326 candidates and 709 confirmed) exoplanets orbiting other stars. Now Nancy Atkinson on Universe Today reports that a new study using gravitational microlensing suggests that almost every star in our galaxy has at least one planet circling it. “We used to think Earth was unique in our galaxy,” said Daniel Kubas, a co-lead author of a paper that appeared in the January 11, 2012 issue of the journal Nature. “But now it seems that there probably are billions of planets with masses similar to Earth orbiting stars in the Milky Way.”
Most of these extrasolar planets were discovered using the radial velocity method (detecting the effect of the gravitational pull of the planet on its host star) or the transit method (catching the planet as it passes in front of its star, slightly dimming it.) Those two methods usually tend to find very large planets that are relatively close to their parent star; circumstances that are not conducive to life as we know it. But another method, gravitational microlensing — where the light from the background star is amplified by the gravity of the foreground star, which then acts as a magnifying glass — is able to find planets over a wide range of mass that are further away from their stars.
Gravitational microlensing method requires that you have two stars that lie on a straight line in relation to us Earthlings. Then the light from the background star is amplified by the gravity of the foreground star, which thus acts as a magnifying glass. A large international team of astronomers used the technique of gravitational microlensing in a six-year search that surveyed millions of stars. “We conclude that stars are orbited by planets as a rule, rather than the exception,” the team stated. They also found that smaller planets, such as super-Earths or cool Neptunes, must be more common than giant ones like Jupiter.
This means that life. which arose early in our planet’s history, is very wide spread in our galaxy. Self aware, intelligent, tool making, language using, lifeforms are much rarer, since it took 99% of Earth’s history for such forms to arise on Earth. However, if there are many millions of Earthlike planets, there should be many thousands of planets inhabited by intelligent creatures. We are not alone. Many religious leaders will object to this idea because they believe that humans are at the center of God’s concern. Does not the Torah teach that humans are created in the image of God? As a Rabbi I would say YES; but God’s image does not refer to a physical form, because God does not have a body and does not incarnate into a physical form. God’s image refers to a spiritual dimension; the combining of free will, moral choice, artistic creativity, and the spiritual ability to experience awe and religious insight.
As a Rabbi, I have no doubt that when we are able to communicate with extraterrestrial intelligences, we will find that they all have various religions and forms of art, Those who believe that their religion is the only true one will be in for a true shock.
- About one out of every ten stars has an earth size planet in the habitable zone per a gravitational microlensing survey (nextbigfuture.com)
- Microlensing Study Says Every Star in the Milky Way has Planets (universetoday.com)
- Exoplanets more common than stars, galactic census finds (news.cnet.com)
- More planets than stars? – BBC News (bbc.co.uk)
- Milky Way Galaxy Shown to Be Teeming With Planets (wired.com)
- Most stars in our galaxy have planets, study suggests (csmonitor.com)
- Study says every star has planets (bbc.co.uk)
- Billions of potentially populated planets in the galaxy (go.theregister.com)
- The Milky Way Contains at Least 100 Billion Planets According to Survey (spacefellowship.com)
- A wealth of habitable planets in the Milky Way (eurekalert.org)