How do we define a habitable planet?

Question

Out of the about 200 extrasolar planets discovered have we found any than can be characterised as habitable?

I know that a habitable planet is a planet that can sustain life (dah).... What i want to know is the official scientific definition of a habitable planet.

Answer 1

Planetary habitability is the measure of an astronomical body's potential to develop and sustain life.

Answer 2

We can't tell if their habitable by *something*. We haven't found any earth-like planets, because, by definition, they have to be relatively small (otherwise the gravity is too great, or it's a gas giant like jupiter)

When viewed from many light years away, a planet will be VERY close to the star about which it orbits, its sun. The planets are too close to see except using some pretty advanced techniques (using the gravity of intervening stars to deflect some of the light, stuff like that). In any case, we can't see smaller planets.

We first detect these planets by noting a slight wobble in the position of a star, as the gravity from a planet moves the star slightly. Problem is, a wobble from a planet like the earth would be so slight we'd never see it.

So no matter which method we use, our instruments and techniques are not precise enough to detect a planet that would be considered earth-like. We can only detect very large and heavy planets.

Answer 3

There are lots of factors to consider. First, the atmosphere must contain the essential gases to sustain life. If a certain planet lacks a particular gas or has some other gases (which might be poisonous), I don't think life is possible. Another is the temperature because if the organism cannot tolerate it, it will die. Another reasons are the abiotic factors like water, soil to name a few.
Generally, a habitable planet depends upon the organism that will be staying in that particular pLanet.
I don't know if there aRe any though other pLanets but astronomers are studying some of them.
Do y0u want to be a habitue of a pLanet without light, water, soiL, air, etc.? :-)

Answer 4

Planetary habitability is the measure of an astronomical body's potential to develop and sustain life. It may be applied both to planets and to the natural satellites of planets.

The only absolute requirement for life is an energy source but the notion of planetary habitability implies that many other geophysical, geochemical, and astrophysical criteria must be met before an astronomical body is able to support life.

In the search for life beyond earth scientists look for (in a particular heavenly body)

a. Adequate temperature,
b. Water in the form of liquid
c. Distance from the energy source.

Answer 5

believe it or not, many planets are habitable. We just need teraforming. The problem is alot of planets we find are not solid, their very gaseous. And the ones that are solid are either frozen stiff or too hot to get near.

Mars is a great example. After years of teraforming it'll be habitable.

Alot of the planets that seem habitable need to be extensivly researched for poison gases, water, fertile land...The Human race is highly specified. They found a planet (not sure which) that was almost exactly the replica of earth but was so abundant in nitrogen that it was deadly.

Another problem is transport. Some of these planets are lightyears away...I could say alot here, but it'd be maddening. There are so many factors that we dont even know about. Who's to say that these planets arnt already inhabited? The answer would be "well, look at them through a telescope. duh"...Buzz, it's not that simple.

Answer 6

In order for a planet to substain life as we know you must follow the water(as nasa puts it). But thats for our planet, if you look at Saturn's moon titan - It's got liquid methane cycling through it's atmosphere. If you look at Jupiter's moon Europa it's possible that it has liquid water inside its crust.

Typically you want a planet that has seasons, just the right position from a orbiting star, magnetic field, liquid metalic core or instead of the right position from the sun you might want a planet that can heat it self.



We define a habitable planet base on what we see on earth, there could be entirly different forms of life that don't follow earth.

Answer 7

an habitable planet needs to be small, rocky and temperate to sustain liquid water, planets that were discovered are all of the gas giant type, since the discovery is based on the relative size and mass of the mother star and the planet, astronomy is yet unable to detect the smaller, rock type planets, that are not too heavy to become gas giants.
Of course, we might discover someday that even gas giants can evolve some sort of life, but it would certainly not be the carbon - water - oxygen type of life as on earth.

Answer 8

habitable means that it can maintain life. Carbon based life usually. It is hard to views other planets and know exactly what they are made of. We know the gas make up of the planets in our system, but it is based on information we have here on our planet. But the periodic table is unique in that it is complete for the universe, all the major chemicals are already know, anything ealse whould be man made.

Answer 9

No, there are no other plants yet that I know of that have been categorized as habitable. The planet must be capable of supporting life.

Answer 10

Did you hear about subtle body? It is known to some as aura. Did the scientists look after this kind of living entities on other planets who have only auric body? No. So, how anyone can conclude that life on other planets must be exactly the same like in our planet? According to the Vedas there is life in every planet. Somewhere the habitants have ethereal body, somewhere airy or made from the element of mind, intelligence.

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