Why does earth have living organism on earth but not any other planet?

Answer 1

Short Answer:

Earth has an atmosphere and a mix of elements at a temperature that permitted

the complex chemistry of life to take place. Venus is believed to be far too hot for life and Mars has no atmosphere to speak of, so while there may have been life on these planets in the past, there is not likely any life now or it is likely to exist in a highly simplified form. All other planets in our Solar System are either far too cold or far too hot to entertain the existence of such complex chemistry. The only exceptions that may exist are moderate warmth subterranean environments that we have not yet investigated.

Longer Answer:

The requirements for life to exist on other planets is certainly not a well defined thing, but the subject of astrobiology

is quite advanced and has some things to say.

There are some basic elements that are expect to be required for life on other planets, either in our Solar System or on planets around other stars.

In the simplest view, there should be water and enough warmth for complex chemical reactions to allow the existence of life. The existence of liquid surface water must be accompanied by an atmosphere. The presence of complex chemistry, most likely carbon-based

chemistry, implies the planet was formed through processes that favored accumulating such lighter atoms as carbon, nitrogen, oxygen, calcium, etc. on the surface.

For the chemistry of life to exits it is assumed that water must be involved and must exist in a liquid state. Depending on the particular star and the details of the atmosphere of a planet, there is a range of distances that a planet for even this basic requirement for life to be met. That range of distances is called the "habitable zone." For our solar system, the habitable zone may range from 0.725 to 3.0 astronomical units, but various scientific models make narrower estimates.

Based just on this issue of the Sun's energy, Venus, Earth and Mars are inside or close to the habitable zone and that zone will change over the next billion years as the Sun's energy output increases as it has for the last few billion years.

There are estimates that there may be half a billion planets occupying habitable zones around stars in our Milky Way galaxy.

Answer 2

theres no oxygen