One Hundred Billion Trillion Habitable Planets

February 23rd, 2009 | Posted by paul in Uncategorized - (Comments Off on One Hundred Billion Trillion Habitable Planets)

274_FirstSeasAccording to Alan Boss, speaking at the American Association for the Advancement of Science’s annual meeting in Chicago, there are one hundred billion trillion habitable planets in our visible portion of the universe. Put another way that’s 1020 habitable planets, or about 15 Billion habitable planets for each and every human being alive today. This single statement along the Kepler launch on March 5th, whose specific mission is to look for habitable planets, has pushed the search for earth like planets to the top of the news.

Alan Boss has written a new book The Crowded Universe which covers his premise. TheTelegraph quoted Boss on the matter in an early report on his presentation:

 “If you have a habitable world and let it evolve for a few billion years then inevitably some sort of life will form on it,” said Dr Boss.

“It is sort of running an experiment in your refrigerator – turn it off and something will grow in there.

“It would be impossible to stop life growing on these habitable planets.”

We shall soon find out about the likelihood of earth like planets over the next four years as Kepler scans a portion of space called the Cygnus-Lyra region (which contains 100,000 target stars). This will be the first time we will have the ability to detect earth-sized planets orbiting within their habitable zone, where liquid water can exist on it’s surface. This will be accomplished by using an extremely sensitive 95 megapixel array of charged coupled devices (CCD).

Below is the area of the ski Kepler will look at.



Habitable Planets May Be Common

February 9th, 2009 | Posted by paul in Uncategorized - (Comments Off on Habitable Planets May Be Common)


From the story:

Our own solar system and Milky Way galaxy are home to billions more planets than currently believed, greatly increasing the prospects of finding at least primitive forms of life out there.

Astronomers described new evidence here yesterday suggesting that anywhere between 20 and 60 per cent of all the sun-like stars in our local galaxy are good bets for forming so-called rocky planets, like Earth and Mars.

University of Arizona researcher Michael Meyer, who led the study, said he personally believes that more powerful telescopes will eventually reveal that every sun-like star “will have a rocky planet around it and the diversity of conditions on them will be huge.”

Between 5 and 10 per cent of the 200 billion stars in the Milky Way galaxy are considered sun-like, depending on the strictness of the definition. That would still mean a minimum of 4 billion stars with rocky planets using the lowest percentages.

Its’ refreshing to finally see empirical evidence catch up with what I long thought was a natural by-product of stellar formation.  When a star forms inside a stellar remnant of a previous supernova its gravity accretes the matter inside it’s influence.  Over time, this orbital debris gravitates towards heavier bodies, forming larger and larger chunks with their own increasing amount of gravitational attraction.  Over time all the smaller debris falls into the remaining larger bodies, forming moons and if enough, rocky planets.

Depending on the amount of stellar debris, the amount of stars that form planets will vary in amount and size, but as this study suggests, it’s between 20 to 60 percent of them.   If planets are this common, then the number and frequency of planets within a stars habitable zone increase tremendously.

The next question is how often does life form if conditions are right?  So far, the evidence seems to indicate that this is a relatively common occurrence too, as the basic building blocks of life are already existent in the stellar environment.


A Cosmic Filter?

August 29th, 1998 | Posted by paul in Uncategorized - (Comments Off on A Cosmic Filter?)

Calculating how often alien civilizations might occur, has been the pre-occupation of scientists for decades. The first person to really formulate such an answer was Frank Drake using his now famous Drake Equation.

The trickiest part of calculating this equation is determining the probability for each variable. Over the years, our knowledge of astrophysics and planetology has increased substantially. For the most part, the probability for the occurence of life has increased along with the discovery of extreme forms of life here on Earth. Life has been found in the coldest reaches of the artic and the deepest parts of the oceans. There is one type of archae-bacteria whose natural habitat is boiling water.

Discovery of planets within a few lightyears of our own star system has upped the ante even further. More surpirsing is the types of planets we are finding, including the recent discovery of 3 planets orbiting a pulsar.

If life does manage to get started, it has a long up hill battle to survive. Assuming that a complex ecosystem manages to encompass a planet, it then has to contend with the possibility of periodic asteroid impacts, nearby supernovas, and deadly gamma-ray bursts.

Of all of the things most likely to extinguish life, one of the more menacing are the gamma-ray bursts originating from the collisions of two or more neutron stars. Radiation from such a collison is so powerful, that it has the potential to wipe out planetary life from a distance of 50,000 light-years. Lucky for us, such collisions only occur in our galaxy about every 100-200 million years. However, in a universe as large as ours, such bursts our detected by our instruments almost once every second!

We can count ourselves lucky that life on this planet has survived the past 4 billion years and is now we ready to leave the womb planet. I suspect we will also soon gain the ability to predict when such deadly gamma-ray burst will occur and get out of harms way when neccessary. Simply postioning yourself on the opposite side of a planetary body as the incoming gamma-ray burst should do it. As intelligence increases so does our chances for survival. My hypothesis is that ultimately no upper limits exist to a suffieciently advanced intelligence.

Either way, such collisions suggest the possibility that advanced spacefaring cultures are very rare, as most life gets irradiated before it evolves the ability to leave!