Planets Planets Everywhere!

Planets Planets Everywhere - Are there some with water to drink?

There has been a search going on for extra-solar planets for a long time. It has been going on seriously for a couple of decades and there has been some success in finding them. Perhaps most people are not as familiar as I am with the fact that there has been success in finding these planets.

The planets found so far tend to be very large ones, many would dwarf Jupiter and many orbit their sun much closer than the planets of our own solar system. As of July 16, 2008 there are 307 candidates detected according to "The Extrasolar Planets Encyclopaedia" on their Catalogue Page. Of course that is "candidates" rather than saying "planets" as it is rather hard to prove completely without any possible doubt. That site I found not really for the casual reader but has a ton of very current information on it.

I find the Wikipedia Page on it -- "Extrasolar planet -- Wikipedia, the free encyclopedia" -- to be a much more interesting and digestible read. (image to right -- image from Wikipedia)

While most of the planets detected have been huge rating up to 13 times the mass of Jupiter which is the limiting mass beyond which a body is considered a Brown Dwarf Star rather than a planet in part this is because it is much easier to detect the much larger bodies using the only techniques we have. Also most of the planets we have detected are close to their suns and tend to be around smaller suns for similar reasons. A very large planet orbiting close to a small star is much easier to detect. The planet is larger in ratio to the sun and moves faster so the changes that are made are easier to observe.

We are detecting smaller bodies even so. From this we seem to be able to predict that the low mass planets may outnumber the Jupiter-like planets by a facter of 3 to 1.

Sometimes they seem to be a bit picky and arbitrary on things like definitions of what a planet is though... that is why Pluto is no longer considered a planet. According to the International Astronomical Union, the working definition for extrasolar planets established in 2001 and last modified in 2003 are:

1. Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars or stellar remnants are "planets" (no matter how they formed). The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our Solar System.

2. Substellar objects with true masses above the limiting mass for thermonuclear fusion of deuterium are "brown dwarfs", no matter how they formed nor where they are located.

3. Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub-brown dwarfs" (or whatever name is most appropriate).

It seems that free-floating planetary-mass objects (planemo) or "rogue planets" or "interstellar planets" aren't included in the discussion on the Wikipedia page.

Personally I think it is very short sited to have a definition of "planet" that is dependant on orbital characteristics. I think that more important should be structure, size, and origin. In my definition, many of the larger moons would be included as planets. There would be ice planets and rock planets, There would also perhaps be a few varieties of gas planet and then there would be the "space junk" which in my definition would be masses which weren't large enough to form into a relative sphere. Thus a body like the earth which formed around another star, but which was thrown out of its orbit and captured by a gas giant or perhaps becomes free floating in interstellar space would still be a planet. But that is my personal view.

It does seem to me that if we can ever figure out some exotic interstellar propulsion system or other method of interstellar transport, there just might be reason to go to other stars. There seem to be other planets to look at and some might be like ours. System of 55 Cancri compared with our Solar System. (image to left -- image from Wikipedia)

Later!
~ Darrell

92.

Beautiful Bridges

Bridges Bridging More Than Just Gaps

I was web surfing a bit today and using StumbleUpon when I came upon this great page with pictures of Amazing Bridges from Around the World. I recognize many of the bridges but many of them are new to me and the pictures are just awesome.

Sometimes we just have to stop and smell the roses. It is worthwhile just to look at beautiful pictures taken of things some of us might take for granted. Some of these bridges, like the Capilano Suspension Bridge (image to right) - which is local to me - are specifically intended to be there to be appreciated or at least there for the appreciation of the beauty of their surroundings.

There are other bridges that are marvelous and special for historical and archeological value as well as aesthetics. The Amazing Bridges from Around the World page has bridges like those and all sort of other amazing bridge images as well. The place where I might fault the page with is that there are no captions to go with the images and along with captions credits for the photos.

There are gems like these to be found around the web and they are - I believe - really in the form of blogs, though being used for special purposes. Another I perused today was of the 10 Tallest Waterfalls On Earth (image to right)and was also a great collection of waterfalls, some familiar and others unfamiliar all illustrated by great photos.

Probably I won't see most of these places, but I can dream and I can look at the pictures others have taken. I can even go to some places both near and far and take my own pictures to share with others and it is much, much easier to share what I see and hear today than ever before... of course there is also so very much more to go through so in a sense even as the World is growing smaller... it is also growing larger by leaps and bounds. We might need more bridges

Later!
~ Darrell.

62.

Life On a Fragile Planet

Life - Elsewhere?

From time to time I hear fairly educated people talking about the importance of space travel and one part of there argument goes that right now we have all of our eggs in one basket - the Earth - and if there were to be a global catastrophe human life would disappear from the universe. They go on to say that with global warming that catastrophe may be coming and that we could be looking at "terraforming" Mars or Venus for mankind to call homes and thus avert this possible catastrophe.

Maybe I have just read too much, but I see some flaws in this. The first and biggest one is that the "terraforming" of Mars or Venus is a project many orders of magnitude greater than actually controlling any problems of global warming that we might have created unintentionally or that might be happening naturally and that with the Earth we are starting with something a lot closer to what we want to end up with than where we would be starting with Mars or Venus. That being said, it only speaks to the issue of space exploration in order to escape from the damages caused by global warming. Meaning that if we can terraform Mars or Venus - then surely we can cure the problems of global warming on the Earth.

Granted at some time in the future, we might want to spread our wings and spread humankind into space in the Earth-Moon system and beyond. Mars is a obvious candidate for we could with our current technology probably figure out ways to survive there. Venus might take a bit more for it would be like trying to set up camp in hell. I think the atmospheric pressures on Venus are like that of being deep undersea and the temperatures enough to melt lead in an atmosphere with enough of a sulphuric acid content to etch any metal you might have in your kitchen.

It would be simpler to create some sort of space colony than to live on Venus probably. Of course that is compared with converting the whole planet into another Earth. There is also a concept where you start by covering an area with a kilometre high dome and creating your biosphere under it and then gradually in a modular fashion expanding the area covered until potentially the whole planet is covered. That is called Paraterraforming or the "worldhouse" concept. Perhaps not with Venus, but perhaps Mars or even the Moon.

It does lead to questions like do we want to do something like convert Luna into another Earth? No longer would we have that creamy white or silvery white orb shining down on us, but would have a much brighter white and blue one potentially. We lose something to gain something. We do that every time a city expands.

Cities - which are most often built in a location where the farming was best - expand and most often cover up the adjacet farmland. You lose farmland when you gain residential and commercial land.

That is a lot like that expansion of mankind to a "New Earth" on the Moon. We lose the Moon and gain a New Earth.

The near future Moon missions planned by a number of countries of the world might lead to permanent colonies on the Moon which might in turn lead to thoughts on Paraterraforming the Moon. How much change to the appearance of the Moon are we going to be expected to accept? Should the general "man on the street"* have any say in it?

What of other places? How about "Earth Orbit"? The International Space Station is very visible from the surface of the Earth and in fact you can find charts and tables telling you when and where you might spot it flying overhead. I'm not sure but an observant person with a good set of eyes or binoculars might be able to even spot it during the daytime?

Will there be a time when the sky might be visually "crowded" where there will always be a number of objects flinging across the night sky - not unlike being near a major international airport at night? I rather enjoy watching planes go by, but there might be a time when there will be no place on Earth that one might escape that aspect of civilization without benefit of a cave or very steep mountain valley.

I don't know if we'll ever build cities in space - large rotating colonies where people can live in a shirt-sleeve environment essentially as if they were on the Earth. If they are in Earth-orbit they will be very visible. I wonder how safe we would ever be able to make them?

I wonder if we will have colonies on the Moon, Mars, and other Terrestrial and Ice Bodies of the Solar System? Will we have interstellar space colonies - which are travelling off to other stars where it will only be the decedents of the people who start off who reach them, and who essentially in the meantime are dwellers of the space between the stars?

I think that before we have the technology to terraform other planets, that same technology would allow us to save the Earth from any sort of runaway ecological disaster. But in the meantime I know we have to take care of our fragile planet. It is the only one we have.

Later!
~ Darrell

44.

__________
* Yes I mean the gender neutral "man" and in "humans" or "mankind".