The Milky Way's Alien Planets --160 Billion and Counting! (Weekend Feature)

 

           

 

The Kepler Space Mission's search for habitable planets is in a tiny window representing 1/400th of the Milky Way. "We used to think that the Earth might be unique in our galaxy," said Daniel Kubas, of the Paris Institute of Astrophysics. "But now it seems that there are literally billions of planets with masses similar to Earth orbiting stars in the Milky Way."

According to an analysis of Kepler data this past January, each of the 100 billion or so stars in our galaxy hosts at least 1.6 planets, bringing the number of likely exo worlds to more than 160 billion. Recent research conclude that large numbers of these exoplanets are likely to be small, rocky Earth-like low-mass planets, which appear to be much more abundant than large ones.

"This statistical study tells us that planets around stars are the rule, rather than the exception," said study lead author Arnaud Cassan of the Paris Institute of Astrophysics. "From now on, we should see our galaxy populated not only with billions of bright stars, but imagine them surrounded by as many hidden extrasolar worlds."

To date, astronomers have discovered more than 700 planets beyond our own solar system, with 2,300 additional candidates found by NASA's Kepler space telescope awaiting confirmation.

In the study, the researchers looked at data gathered by a variety of Earth-based telescopes, which scanned millions of stars from 2002 to 2007 for microlensing events, then closely analyzed about 40 of these events and discovered that three betrayed the presence of an alien planet around a star. One of these planets is a bit more massive than Jupiter, one is comparable to Neptune and the third is a so-called "super-Earth" with a mass about five times that of our home planet --an impressive yield considering how perfectly aligned multiple bodies must be to yield an explanet detection via microlensing.

Further, according to the researchers' calculations, every planet in the Milky Way harbors an average of 1.6 planets in the 0.5-10 AU range, which in our solar system corresponds roughly to the swath of space between Venus and Saturn.( Since astronomers estimate that our galaxy contains about 100 billion stars, that works out to at least 160 billion alien planets. The true number of alien worlds may be quite a bit larger than 160 billion. Some planets hug their host stars more closely than 0.5 AU, after all, and others are more far-flung than 10 AU. And a great many likely have no host star at all.

 

               

The Daily Galaxy via Kepler Mission and Nature

Comments

[Simon Salosny]

Habitable planets? Considering the characteristics of Earth, such as its core parameeters, chemical mix, atmosphere, magnetosphere, H20, C02, etc., gravity; size, distance and temperature of our sun, where a few degrees +- govern the possibilities of survival, plus a series of other parameters that should be taken into consideration. Any statistical possibility for biologically similar to earthern type life to be developed?

[Matthew]

You assuming life has to arise given only those parameters. Life here on Earth does not always follow those parameters. We have different types of life that can live without oxygen, sunlight, or water here on Earth. A recent test on the space stations exterior confirm that certain types of photosynthetic bacteria can survive exposure to the vacuum of space and still live on after over a year. Bacteria has proven to be a very versatile form of life, capable of thriving in the most extreme of environments. I don't think we can assume anymore that our planet alone is the perfect model for life to arise.

[Matthew]

You are* sorry had a long night.

[John Christopher Sunol]

I beleive that Planets in our Universe are so numerous that we have not even touched on what is out in space yet. We have an eternity to learn about this

[kristi276]

When we look for life outside ourselves we seem to use us as a template for what would like be like outside of our solar system. We look for all of the conditions that gave rise to like on Earth, assuming that all life would be just like us. We are babes in the wilderness and we do not know how life would be, hot of the homo sapiens-sapiens model. Is life like a snow flake? Can we say with 100 percent certainty that life on exoplanets would be just like us. What would happen if we do find microbial life in the liquid methane of Saturn, or microbial life in the frozen plains of Europa?

When will we find out that we are not the crown of creation?

[kristi276]

The count of 160 billion planets in the Great Milky Ocean is quite astonishing, there may be over one trillion planets in the galaxy. If there are a trillion planets in the galaxy, what is the percentage of planets with life on them, life not as we know it? As we launch the James Webb Telescope and other modern infrared telescopes, how will our view of the galaxy we live in be changed forever. So far we have not developed the technology to actually see an exoplanet, what will happen when we will have an actual photo of a planet outside out solar system. We have four rocky planets, four gases planets and five dwarf planets in our system. Who would be the first human to land on a exoplanet, and in what millennium?

One small step for a woman, one giant step for humankind.

[Winwin4all]

Thank you for the confirmation info regarding the size of our galaxy. I've known a similar number (178 billion planets) back in 1996 and it just feels good that similar info is coming out.

LoLaL (lots of love and light) to all truthseekers as the "TRUTH" shall prevail.

[Mark D]

This isn't really surprising and yet it is a 'revelation' that we can establish and verify so many exoplanets.

Perhaps we will also develop the ability to actually scan the surface of these planets in great detail. This is a certainty surely, that within my life-time we shall be looking at digitally enhanced images... a 'google-galaxy' selection as it were, of super-earths, rocky planets, binary systems and who knows... evidence that at least one or more of these environments is the product of a living ecology or indeed, evolving civilizations of some kind.